CN116286640A

CN116286640A - Application of apoptotic bodies in inducing macrophage polarization and promoting wound healing

Info

Publication number: CN116286640A
Application number: CN202310349741.XA
Authority: CN
Inventors: 孙晓明; 毛佳怡; 火海钟; 钱姝桐; 赵秋羽; 赵彬帆; 刘芷默; 卢博伦; 张柳成; 毛曦嫒; 崔文国; 张余光
Original assignee: Ninth Peoples Hospital Shanghai Jiaotong University School of Medicine
Current assignee: Ninth Peoples Hospital Shanghai Jiaotong University School of Medicine
Priority date: 2023-04-02
Filing date: 2023-04-02
Publication date: 2023-06-23

Abstract

The application of apoptosis bodies in inducing polarization of macrophages, wherein the apoptosis bodies can be used as active substances to reverse the elevation of JAK-STAT1 axes and lighten the inflammatory polarization, thereby regulating and controlling the polarization of the macrophages to M2 type, and the polarized macrophages can lighten inflammation and promote angiogenesis by influencing the biological process of HUVECs. Through verification, the apoptotic bodies realize the treatment effects of inflammation regulation, blood vessel regeneration and tissue regeneration in the wound healing process by regulating macrophages, and a novel safe, convenient and easy-to-store administration and treatment method with practical application effects is provided for anti-inflammatory and pro-regeneration treatment of diabetes wounds.

Description

Application of apoptotic bodies in inducing macrophage polarization and promoting wound healing

Technical Field

The invention relates to a medical product made of biological materials, in particular to an extracellular vesicle for removing unknown cell contents, which has safety and is used as a delivery carrier, thereby being beneficial to promoting wound repair.

Background

Wound surface is formed by the following steps: but are not limited to external force, heat, electricity, chemicals, and low temperature, and such external injury factors as: damage caused by physiological function changes such as local blood supply disorder. Clinically, the wound is divided into an acute wound and a chronic wound according to the healing period of the wound, the chronic wound is generally characterized by difficult healing, and the chronic wound is generally obtained after more than two weeks of tissue defect repair, and is mostly accompanied by other diseases, such as: diabetes mellitus, common incised wounds, bruises and the like are all acute wounds.

Neovascularization is a critical process driving ischemic tissue repair, however for chronic (difficult to heal) wounds, the long-term hypoxic microenvironment results in insufficient vascularization and thus delayed wound healing. Endothelial cells, which are key cells constituting new blood vessels, clearly play a central role in the vascularization process.

CN202211118736.X discloses a magnesium hydride loaded microneedle and its application in wound healing, wherein the microneedle patch comprises a support layer and a microneedle, the needle body of the microneedle is made of biodegradable material, and the needle tip contains MgH ₂ . In vitro and in vivo verification shows that MgH is loaded ₂ The microneedle patches of (a) can promote the wound healing process, promote the polarization of M2, enhance the proliferation and migration of cells, improve angiogenesis and reduce ROS production.

CN202211169998.9 discloses a silver-containing microcarrier comprising ascorbic acid, ag ⁺ And a coating agent having a structure of "flower-like" and a surface area of 106.5m ³ /g±20m ³ And/g, the mesoporous material has mesoporous characteristic, and the pore diameter range is 5 nm-225 nm. Silver-containing microcarriers were verified to release Ag in response to environmental ROS ⁺ The exosome is loaded, so that the resistance of the exosome to oxidative denaturation can be improved, the stability of the exosome is improved, and the exosome is prevented from being rapidly damaged to be inactivated. Exosome-loaded microcarriers are delivered to the wound surface, such as: after the diabetes wound surface, bacteria can be effectively eliminated, and the apoptosis of damaged oxidized cells is promoted, so that the regeneration microenvironment is improved, exosomes are delivered and continuously released at target sites, the biological functions of fibroblasts and endothelial cells are regulated, the angiogenesis is promoted, and the wound surface healing is accelerated.

Prior studies have demonstrated that Adipose stem cells (adiose-derived Stem Cells, ADSCs) are important daemons for inflammatory regulation (Stem Cell Res Ther (2022), 149;Nature Medicine 15 (2009), 42-49;Molecular Therapy 20 (2012), 14-20). Inflammation prolonged is a critical issue in chronic skin wounds, and transplantation of ADSCs into the wound microenvironment can accelerate skin wound healing, restoring more complete and ordered skin structure. In the treatment of chronic wound healing, the promotion of anti-inflammatory and tissue repair regeneration by such transplantation has been demonstrated by a number of experimental studies (Nature Biomedical Engineering 5 (2021), 379-384). However, applications of ADSCs also exist such as: 1) ADSCs used as cell therapy require in vitro culture and isolation, and involve the problem of uncertain multi-directional differentiation of stem cells such as osteogenesis, adipogenesis and chondrogenesis; 2) ADSCs can promote proliferation and vascularization of tumor tissues, increase the risk of tumor formation, and has an undefined action mechanism; 3) Massive apoptosis of ADSCs after transplantation was observed in a short time in wound healing models, and the biological functions involved were also a problem to be further studied (Cell Death Discovery7 (2021), PMID:33246491; stem Cell Res Ther 11 (2020), 507). These problems have prevented the use of ADSCs in the field of wound healing therapies. Therefore, it is currently highly desirable to define the specific action mechanism of ADSCs, and explore effective ways to enhance the action effect of ADSCs on the basis of the specific action mechanism, and reduce unnecessary side effects.

Disclosure of Invention

An object of the present invention is to provide an application of apoptotic bodies in inducing polarization of macrophages, wherein the apoptotic bodies are used as active substances to regulate expression of JAK-STAT1 signal paths.

Another object of the present invention is to provide an application of the apoptotic body in inducing polarization of macrophages, wherein the apoptotic body is used as an active substance to induce polarization of macrophages to M2 type.

It is still another object of the present invention to provide an application of apoptotic bodies in inducing polarization of macrophages, wherein the apoptotic bodies are used as active substances to influence the biological process of HUVECs so as to promote angiogenesis.

The invention also aims to provide an application of taking the apoptotic bodies as active substances in preparing medicines for promoting the healing of chronic wounds (such as diabetic wounds).

The fifth aim of the invention is to provide an application of using the apoptosis body as an active substance in preparing a medical device for promoting the healing of chronic wounds (such as diabetes wounds).

Apoptotic Bodies (ABs) are a major class of extracellular vesicles (Extracellular Vesicles, EVs) that are formed by the breakdown of apoptotic processes formed following programmed cell death (Nature Reviews Drug Discovery,2022, 21, 379-399). Apoptosis of fat stem cells induced by staurosporine (STS) can obtain apoptotic bodies with a diameter of 550 nm-1200 nm.

The regulation of arginine metabolism by JAK1-STAT1 is thought to be an important metabolic regulator regulating macrophage polarization and inflammatory response (Molecular Cell 82 (2022), 527), and the elevation of JAK-STAT1 signaling pathway leads to an increase in arginine succinate synthase (ASS 1), causing macrophage polarization to inflammation. While ABs can reverse the elevation of the JAK-STAT1 axis and reduce this inflammatory polarization, thereby modulating the polarization of macrophages to M2 type, the polarized macrophages can reduce inflammation and promote angiogenesis by affecting HUVECs biological processes.

Through further verification of the diabetic wound animal model, ABs reverses the rise of the JAK-STAT1 signal pathway, and directly appears to promote the healing of chronic wounds on a tissue level. Thus, apoptotic bodies are useful as agents for non-therapeutic purposes for modulating JAK-STAT1 signaling pathways, in cellular levels, or even in responses or biological functions generated by the physiology of the body.

ABs prepared by the invention is used as an active ingredient for targeted regulation of macrophage polarization, thereby being beneficial to promoting (such as chronic diabetes) wound healing. ABs and other adjuvants are mixed to make into medicine (preparation) for repairing diabetic wound.

These pharmaceutical excipients may be used conventionally in various formulations, such as: but are not limited to isotonic agents, buffers, flavoring agents, excipients, fillers, binders, disintegrants, lubricants, and the like; may also be selected for use in response to a substance, such as: the auxiliary materials can effectively improve the stability and the solubility of the compounds contained in the composition or change the release rate, the absorption rate and the like of the compounds, thereby improving the metabolism of various compounds in organisms and further enhancing the administration effect of the composition.

In aqueous injection solutions, the auxiliary materials generally comprise isotonic agents and buffers, and necessary emulsifying agents (such as Tween-80, pluronic, and Poloxamer), solubilizers, and bacteriostats. In addition, the composition also comprises other pharmaceutically acceptable pharmaceutical excipients, such as: antioxidants, pH adjusters, analgesics, and the like.

Adjuvants used in preparing liquid preparations generally include solvents, water, oils (e.g., fatty acids), emulsifiers, and optionally preservatives.

Various excipients and vesicles of the invention are formulated into dosage forms useful for administration (drug delivery), such as: but not limited to, aqueous injection, powder for injection, powder, patch, suppository, emulsion, cream, gel, aerosol, spray, powder spray, sustained release agent, controlled release agent, etc. In addition, specific purposes or modes of administration may be achieved, such as: sustained release administration, controlled release administration, pulse administration, etc., and auxiliary materials used, such as: but are not limited to, gelatin, albumin, chitosan, polyethers and polyesters such as: but are not limited to, polyethylene glycol, polyurethane, polycarbonate, copolymers thereof, and the like. The main expression "advantageous administration" is referred to as: but not limited to, improving therapeutic effect, improving bioavailability, reducing toxic side effects, improving patient compliance, and the like.

Drug-containing medical devices that combine drugs with medical devices have also become common, such as: dressing comprising vesicles according to the invention. The vesicle of the invention is also used as an active ingredient to be loaded or coated on a material for preparing a medical device for repairing the diabetic wound. Common scaffold materials are: PLA, PLGA, gelMA and metals, etc. And mixing with biocompatible degradable material to obtain micropins and their micropin array, or loading in metal micropins to obtain micropin chip. When the microneedle is inserted into the skin, ABs is released in the epithelial tissue, so that the healing capacity of the diabetic wound surface is improved.

A composition containing apoptotic bodies, a hydrogel microsphere delivery system (abs@gelma@ms) was prepared using a GelMA hydrogel load ABs with good biocompatibility. The implantation of the GelMA hydrogel microsphere provides an ecological niche for the preservation and slow release of ABs, so that a symbiotic microenvironment is formed together with surrounding cells and tissues, the effect of ABs can be pertinently improved, and the local acting time and concentration of the tissues can be prolonged.

Compared with ABs, ABs@GelMA can better maintain the local effect of ABs in a chronic wound model of a diabetic rat, and ABs realizes the treatment effects of inflammation regulation, angiogenesis and tissue regeneration in the wound healing process by regulating macrophages, so that a novel safe, convenient and easy-to-store administration and treatment method with practical application effects is provided for anti-inflammatory and pro-regeneration treatment of diabetic wounds.

Drawings

FIG. 1 is a representation of apoptotic bodies and GelMA hydrogel microspheres loaded with apoptotic bodies; wherein A1 is a bright field picture of adipose stem cells and the adipose stem cells after STS induction for 12 hours, A2 is a TEM result picture of ADSC-ABs, B is a WB result picture of ADSC and ABs, C is a BCA protein concentration detection result picture, D is a Zeta potential result picture, E is a DLS result picture of ABs, F is an uncrosslinked GelMA@MS bright field picture, G1 is a GelMA@MSSEM picture, G2 is an SEM picture of abs@GelMA@MS, H is a profile fluorescent picture of GFP@GelMA@MS hydrogel microspheres, I is a loading condition fluorescent result picture of Dil@ABs@GelMA@MS, J is a fluorescent picture of GFP@GelMA@MS degradation conditions on D1 day, D3 day, D6 day, D10 day, D14 day and D21 day respectively, K is a fluorescent picture of GFP@GelMA release condition on D1 day, D3 day, D6 day, D14 day and D21 day, respectively, and a fluorescent picture of release condition of the BCA is different in a statistical method; m is an element energy spectrum analysis chart of the GelMA microsphere; element energy spectrum analysis of the loaded ABs GelMA microsphere;

FIG. 2 is a graph of the results of the biocompatibility assays for ABs and ABs@GelMA@MS; wherein A is a schematic diagram of coculture of ABs and HUVECss with different concentrations, B is a CCK-8 detection result of 0-3 days, C is a statistical diagram of live and dead staining results of HUVECs treated by Control group, gelMA@MS group, ABs group and ABs@GelMA@MS, and 'ns' represents: the comparative differences between the groups were not significant.

FIG. 3 is a graph showing the results of phagocytosis of ABs by macrophages and the effect on endothelial cell migration in vitro; wherein, A is a schematic diagram of the process of ABs production, phagocytosis and promotion of vascular endothelial cell migration, B is a graph of the phagocytosis of ABs by macrophages, C is a representative scratch experimental image of HUVECs migration stimulated by a conditioned medium of macrophages after different treatments, D is an endothelial cell migration length statistical graph, and E is an endothelial cell migration area statistical graph;

FIG. 4 is a graph of ABs down-regulates inflammation through the JAK/STAT1 pathway and Arg pathway, as well as effects on in vitro macrophage phenotype; wherein A is a fluorescent schematic diagram of cytoskeleton of LPS and ABs for regulating macrophage morphology, B is a statistical diagram of cytoskeletal length of THP-1 under different treatments, C is a thermal diagram of various inflammatory and anti-inflammatory cytokines in a transcriptome, D is a transcriptome sequencing result diagram of in vitro inflammatory cytokines and chemokines, E is a schematic diagram of ABs for regulating inflammation;

FIG. 5 is the effect of phagocytosis of ABs by macrophages on the phenotype of macrophages in vitro; wherein a is a flow cytometry graph expressed by CD11B and CD206 after the macrophages are differently stimulated by the control group, the LPS group and the lps+ ABs group, B is a flow cytometry analysis graph expressed by CD11B and CD206 after the macrophages are differently stimulated by the control group, the LPS group and the lps+ ABs group, C is a result analysis graph of the relative mRNA levels of JAK-STAT pathway JAK1, JAK2, ASS1 and STAT1 factors, pro-inflammatory factor mRNA levels (TNF- α and iNOS) and pro-healing factor (TGF- β and IL-1 0) mRNA levels (n=3) in three differently stimulated macrophages, D is a WB result graph of macrophages cultured with three different stimulators, E is a PCR analysis of the JAK1 expression of Thp-1-derived macrophages treated with control siRNA (sicrl), JAK2 siRNA (siJAK 2) or STAT 1siRNA (siJAK 1) after 48 hours of stimulation by the three differently stimulated macrophages with PBS, LPS and lps+ ABs, respectively;

FIG. 6 is a graph of the results of ABs@GelMA promoting wound healing; wherein A is DiD ⁺ ABs and DiD ⁺ Bioluminescence result graphs of ABs@GelMA after local wound injection, B is a photograph of conditions of ABs@GelMA for promoting in-vivo wound healing, C is an image of software simulation of a control group, a GelMA group, a ABs group and ABs@GelMA groups for treating wounds on

days

1, 3, 7, 14 and 21, and D is a statistical graph of wound healing areas of each group;

FIG. 7 is a graph showing the effect of various treatment modes on wound healing of diabetic rats; wherein, A is a schematic diagram of preparation and treatment of wound surfaces of diabetic rats, B is an immunohistochemical graph of each group of IL-1 beta, an arrow in the graph indicates a part expressing IL-1 beta, C is a statistical graph of the amount of IL-1 beta in each group, D is an immunohistochemical graph of each group of TNF-alpha, an arrow in the graph indicates a part expressing TNF-alpha, E is a statistical graph of the amount of TNF-alpha in each group, F is a HE staining graph in each group, G is a wound length statistical graph in each group, H is a statistical graph of the number of inflammatory cells in each group, I is a Masson trichromatic staining graph in each group, J is a comparison of collagen deposition areas in each group, and 'ns' indicates: the comparative differences between the groups were not significant;

FIG. 8 is a graph of the results of ABs@GelMA inducing polarization of M2 macrophages and promoting angiogenesis during wound healing; wherein, A is F4/80/CD86 immunofluorescence staining pattern of 7 th day after trauma, B) F4/80/CD206 immunofluorescence staining pattern of 7 th day after trauma, C is alpha-SMA immunofluorescence pattern of 7 th day after trauma, D is F4/80/CD86 immunofluorescence staining statistical pattern of 7 th day after trauma (n=3), E is F4/80/CD206 immunofluorescence staining statistical pattern of 7 th day after trauma (n=3), F is alpha-SMA immunofluorescence statistical pattern of 7 th day after trauma (n=3), G is ABs@GelMA release ABs at wound site, stimulates macrophage polarization into M2 type macrophage, and releases pro-angiogenic cytokines to promote angiogenesis.

Detailed Description

The technical scheme of the present invention is described in detail below with reference to the accompanying drawings. The embodiments of the present invention are only for illustrating the technical scheme of the present invention and not for limiting the same, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications and equivalents may be made thereto without departing from the spirit and scope of the technical scheme of the present invention, which is intended to be covered by the scope of the claims of the present invention.

The test methods used in the following examples of the present invention are specifically described below:

1) ABs preparation and characterization

At 37℃with 5% CO ₂ ADSCs (Shanghai' an biotechnology) were cultured in the medium. When the cells reached 80% confluence, 5. Mu.M staurosporine (STS) (Beyotime Biotechnology, china) was added to the medium and induced to apoptosis for 12h (Sci Transl Med 9 (2017) PMID: 29141887). After pancreatin digestion of the ADSCs, 300g was centrifuged for 20min, the supernatant was collected and the pellet was discarded. Centrifuging the supernatant for 3000g,20min, discarding the supernatant to obtain ABs precipitate, and weighing with 1 XPBSAnd (5) suspending ABs, and storing at-80 ℃ for subsequent experiments.

The morphology of ABs was observed by TEM. ABs particles were resuspended in 1% glutaraldehyde for 30 minutes. Samples were dropped onto a Formvar coated copper grid and incubated for 20 minutes. After washing, the sample was negatively stained with 2.5% uranyl acetate for 2 minutes. Image processing (Biomaterials 284 (2022), 121486) was performed using a JEM-1200EX TEM (Hitachi, HT-7700, japan).

Proteins were measured according to BCA protein assay kit (Beyotime Biotechnology, china).

The expression level of apoptosis-related proteins in ABs and ADSC was examined by western blot. The primary antibodies used included C3B (1:1000) (Proteintech, ab52649, USA), (C1 QC 1:1000) (Abcam, ab75756, UK), H3.3 (1:5000) (Abcam, ab52649, UK), H2B (1:1000) (Abcam, ab52649, UK), beta-actin (1:5000) (Proteintech, 66009-1-Ig, USA). For nanoparticle tracking analysis, ABs was diluted in PBS and analyzed for ABs particle size distribution and potential using a dynamic light scattering device (DLS, zetasizer, malvern, nano-ZS 90).

2) Construction and characterization of ABs-loaded GelMA hydrogel microspheres

Composite hydrogels were prepared by self-contained microfluidic devices (Small 18 (2022), PMID: 35106912). Briefly, 0.25g of lyophilized methacrylic anhydride gelatin (GelMA) (Engineering For Life, china) and 0.025g of lithium phenyl-2, 4, 6-trimethylbenzoyl phosphate (LAP) (Engineering For Life, china) were treated in 5mL of deionized water to pretreat the aqueous phase. 1.5g of sorbitol monooleate (span 80) was dissolved in 30g of paraffin oil and an oil phase was prepared. The hydrogel microsphere prepared by microfluidics is crosslinked by blue light on a circulating refrigeration pump, and is respectively washed three times by anhydrous diethyl ether and deionized water after the crosslinking is finished, so that the GelMA hydrogel microsphere is obtained and is marked as follows: gelMA@MS (Bioactive Materials 6 (2021), 1639-1652).

The prepared microspheres were lyophilized, weighed 2mg and dissolved in the above ABs PBS solution. ABs is adsorbed onto GelMA microspheres by submerged adsorption activity to form ABs loaded GelMA microspheres, noted: gelMA@MS@ABs.

The size of the hydrogel microspheres is controlled by photographing uncrosslinked droplets prepared by a microfluidic device through an optical microscope and adjusting the size of uncrosslinked GelMA droplets by controlling the flow rate ratio of the aqueous phase to the oil phase. The surface morphology of GelMA@MS and GelMA@MS@ABs prepared from microfluidics (Applied Materials Today (2018), 54-63) was observed by scanning electron microscopy (SEM, hitachi SU 5000). GelMA@MS@ABs were prepared with GFP-stained GelMA and Dil (Beyotime Biotechnology, china) stained ABs and observed under a microscope for morphology of microspheres and ABs and distribution of morphology and ABs of microspheres at

days

1, 3, 6, 10, 14 and 21, respectively.

Three groups of 5wt% GelMA polymers with different concentrations ABs (1 mg/ml, 2mg/ml and 3 mg/ml) were studied for their in vitro release behavior at 37 ℃. First, 1 ml of hydrogel microspheres prepared from a polymer solution was added to a dialysis bag (mw=1000). 5 ml of Simulated Body Fluid (SBF) at 37℃was then added to a 15 ml centrifuge tube, the dialysis bag was placed into the centrifuge tube, and the centrifuge tube was placed in a shaking thermostat at 37 ℃. The buffer was removed at the same time each day for measurement and refilled in the same manner. Protein concentration in SBF was then measured using BCA kit and microplate reader. The optimal detection wavelength of the enzyme label instrument is 562 nanometers.

The method for testing the spectrogram comprises the following steps: taking a small sample, directly adhering the small sample on the conductive adhesive, and spraying the small sample on the conductive adhesive for 45 seconds at 10 milliamps by using a Quorum SC7620 sputter coating machine; the samples were then photographed with a ZEISS Sigma 300 scanning electron microscope with an acceleration voltage of 15 kv using a SE2 secondary electron detector.

3) ABs biocompatibility with GelMA@MS@ABs

HUVECss cells and ABs were plated in 96-well tissue culture plates at 1X 10 ⁴ Density Co-culture per well ABs concentrations were 0 μg/mL, 0.5 μg/mL, 1 μg/mL, 1.5 μg/mL, 2 μg/mL, 2.5 μg/mL, respectively, and at 37℃in H-DMEM supplemented with 10% fetal bovine serum, 100mg/mL streptomycin, 100U/mL penicillin (Life Technology) in 5% CO ₂ Is cultured in a wet incubator. Cytotoxicity was analyzed by CCK-8 reagent (ck 04, dojindo, japan). Specifically, 100 μl of 10% cck-8 reagent (DMEM:CCK-890: 10). Incubation was carried out for 2 hours, 100. Mu.L of the incubation supernatant was extracted and OD was measured at a wavelength of 450nm with a microplate reader.

In addition, gelMA@MS@ABs was added to the upper chamber of the Transwell, HUVECss was added to the lower chamber, and the cytotoxicity of GelMA@MS@ABs was studied using the live/dead cell kit (Invitrogen, L3224, US). After 1 and 3 days of incubation, the cells on the scaffolds were stained with 500 μl of the mixed dye for 20 minutes and then observed under a fluorescence microscope.

4) Dil staining and observation of cellular uptake of ABs

To examine the uptake of ABs by cells, ADSC-ABs was stained with Dil, and stained ABs (100 μg) was dispersed in PBS (1 mL) and co-cultured with nuclei of hoechst (Beyotime Biotechnology, C1011, china) stained PMA-treated THP-1 cells according to the manufacturer's instructions. The phagocytosis of ABs by macrophages was observed by fluorescence microscopy.

5) Detection of angiogenesis-inducing ability of ABs polarized macrophages

HUVECs cells at 5X 10 per well ⁵ The density of individual cells was seeded in 6-well plates (n=6) and after overnight incubation, fused monolayers were formed. The gap without cell attachment was scraped with a 200 μl pipette tip. Supernatants of THP-1 cells from control, LPS and LPS+ ABs groups were added, respectively. Images were collected at the same location on the plate on

days

0, 1, 2 and 3. ImageJ software was used to quantify the migration area.

6) Transcriptome analysis of macrophages after LPS and ABs stimulation

Human myeloid leukemia monocytes (THP-1 monocytes) (catalog number TIB-202) were purchased from the collection of typical cultures at the national academy of sciences of China (Shanghai). Symbiont is used for transcriptome analysis of THP-1 cells. Briefly, a six-well plate was added with 5×10 ⁵ THP-1 cells were cultured in 10% fetal bovine serum, 100mg/mL streptomycin, 100U/mL penicillin (Life Technology) RPMI-1640 medium (Gibco, USA) supplemented with 200nM PMA (Sigma, P8139, USA) to stimulate THP-1 cells as macrophages at 37℃and 5% CO ₂ Culturing for 48h. After observing the whole cell adhesion, the supernatant was aspiratedThe solution was washed three times with PBS, 1640 medium was added again to the three groups, 100ng/mL of LPS was added to the LPS group and LPS+ABS group, the supernatant was aspirated after 48 hours, the solution was washed three times with PBS, 1640 medium was added again to the three groups, and 1ug/mL of ABs was added to the LPS+ABS group. Total RNA was isolated using Trizol (Vazyme, china) according to the manufacturer's instructions. The concentration of RNA was measured with a NanoDrop 2000c (Themo, USA) and the mass was measured with an Agilent 4100 biological analyzer (Agilent, USA) (Biomaterials 283 (2022), PMID: 35286850). The RNA sequence library was constructed using a Illumina (Vazyme, china) VAHTS Universal V RNA sequence library preparation kit, and the library was deep sequenced using the paired-end sequencing of Illumina NovaSeq6000 (Illumina, U.S.) according to the manufacturer's protocol (Journal of Ethnopharmacology 294 (2022), PMID: 35589020).

Mapping and enrichment analysis was performed as described previously. Transcriptome sequencing was performed by OEbiotech Co Ltd (Shanghai, china). Clean reads were obtained using Trimmatic and mapped to the reference genome using hisat 2. FPKM (per kilobase exon fragment per million reads) values were calculated for each gene using cufflinks. DEG, GO (gene ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) enrichment analysis. P < 0.05 and FoldChange < 2 or FoldChange < 0.5 were set as thresholds for significant differential expression or differential enrichment.

7) ABs detection of induced macrophage immunomodulation

The culture medium was cultured with RPMI-1640 medium containing 10% FBS. To differentiate THP-1 cells into macrophages, undifferentiated THP-1 cells were seeded at 5X 105 cells/mL and incubated in RPMI-1640 supplemented with 200nM PMA and 10% FBS in a 5% CO2 incubator at 37℃for 2 days. Subsequently, THP-1 cells were treated into three groups, i.e., a control group, an LPS group and an LPS+ABS group, using the above method on day 3. The supernatants/conditioned media of THP-1 cell-derived macrophages, LPS-treated THP-1 cell-derived macrophages, LPS-and ABS-treated THP-1 cell-derived macrophages were collected for further experiments. To verify ABs-induced macrophage immunomodulation, the following experiments were performed:

Observation of THP-1 cytoskeleton. THP-1 cells were washed three times with PBS and fixed with 4% paraformaldehyde for 20 min, treated with 0.1% (v/v) Triton X-100 for 15 min, then washed again with PBS, then stained with 0.2mL 5. Mu.g/mL Actin-Tracker Green (Beyotime Biotechnology, C1033, china) and 0.2mL 10. Mu.g/mL 4, 6-diamino-2-benzindole Dilactide (DAPI) (Beyotime Biotechnology, C1033, china) to label Actin and nuclei, respectively. Finally, cytoskeletal labeled THP-1 cells were examined by laser scanning confocal microscopy (LSCM, LSM800, zeiss, germany).

And (5) detecting flow cytometry. To assess the polarization state of three different treated THP-1 cell-derived macrophages, three groups of THP-1 cell-derived macrophages were stained with CD11b-FITC (eBioscience, USA) and CD206-PE (eBioscience, USA), respectively, and kept at room temperature for 30 minutes. Subsequently, the cells were washed twice with PBS and then analyzed by flow cytometry (FACSAria I; BD Biosciences, UK) (n=3) (Materials 6 (2021), 3218-3230). Data were analyzed using Kaluza software (version 1.2; beckman Coulter, usa).

You quantify your transcription polymerase reaction (RT-qPCR). cDNA synthesis was performed using HiScript SuperMix for qPCR kit (Vazyme, china) and RT-qPCR was performed using Roche 480 real-time PCR detection system (Roche, switzerland). The results were normalized to GAPDH and the 2- ΔΔc method was used. The primer sequences are set forth in Table 1.

TABLE 1

Western blot analysis. Equivalent amounts of protein in THP-1 cell lysates were electrophoresed on a 7% polyacrylamide gel electrophoresis (SDS-PAGE) gel at 120V and then transferred to polyvinylidene fluoride (PVDF) membranes. After blocking with 5% Bovine Serum Albumin (BSA) for 2 hours at room temperature, membranes were incubated with IL-10 (rabbit, 1:1000; affinity, AF0240, china), PDGFB (rabbit, 1:1000; affinity, AF0240, china), JAK1 (rabbit, 1:1000,Cell Signaling Technology,ab2716281, U.S.), JAK2 (rabbit, 1:1000,Cell Signaling Technology,ab2716281, U.S.), STAT1 (rabbit, 1:1000,Cell SignalingTechnology,ab2198289, U.S.), ARG1 (rabbit, 1:1000; abcam, ab203490, UK), and β -actin antibodies (goat, 1:500; proteintech,66009, U.S. (Advanced Science 6 (2019), PMID: 30775235). After four washes with Tris buffered saline tween-20 (TBST), the immune response trace was detected by Enhanced Chemiluminescence (ECL) detection kit (Amersham Biosciences, chal font st. The intensity of protein expression on the membrane was analyzed by Image J software.

Cells were siRNA transfected using Lipofectamine 2000 according to manufacturer's instructions. The siRNA sequence information used is shown in table 2.

TABLE 2

8) Wound assessment of ABs-loaded GelMA hydrogel microspheres and fluorescence imaging analysis of DiD-labeled ABs-loaded GelMA hydrogel microspheres

All experiments were performed according to institutional animal care guidelines. All procedures involved in animal experiments were approved by the Shanghai university of traffic animal research Committee (HKBL-2018-141). Streptozotocin (STZ) (50 mg/kg, i.p) was injected preoperatively. 180-250g male SD rats induced type 1 diabetes model for 8 hours. After 7d, the blood glucose level in the tail vein of the rat was measured to reach 16.7X10 ^-3 M or more. Rats were randomly divided into 4 groups (Control group, gelMA group, ABs group, and abs@gelma group) and anesthetized with sodium pentobarbital by intraperitoneal injection. Then 3 round full-layer skin wound surfaces are manufactured on the back of the rat by using a perforating machine

Using 3M Teg _a The derm film covers the wound, avoiding infection. Changes in wound repair on

days

1, 3, 7, 14 and 21 were recorded with a digital camera, and wound Closure Rate (CR) (Small 18 (2022)) was calculated as follows

CR(％)＝(A0-Ac)/A0×100％

Wherein A0 is the wound closure area on day 0, and Ac is the wound closure area on a certain day.

After collection ABs, ABs was stained according to the instructions of the DiD kit (bi yun, china) for 30min, the dye was removed by centrifugation with 3000g,20min, and ABs was resuspended with PBS, the supernatant was removed by centrifugation again with 3000g,20min, and ABs was resuspended with PBS and repeated twice. Bioluminescence imaging was performed to assess the preservation capacity of transplanted did+ ABs in vivo in mice. Briefly, rats were subcutaneously injected with 500 μl of either DiD+ ABs or DiD+ABs@GelMA near the wound. Rats were anesthetized with 2.5% isoflurane and images were taken using an in vivo imaging system IVIS Lumina Kinetic Series (PerkinElmer) cooled CCD camera at

days

1, 5, 14 and 21 after ABs implantation. After 10min, all rats were photographed for 60s.

9) In vivo evaluation of the role of ABs-loaded GelMA hydrogel microspheres in rat diabetic wound model

ABs on day 7, tissue samples were collected and fixed in 4% paraformaldehyde for 2 days. After paraffin embedding, the tissue samples were cut into 7 μm sections (Chemical Engineering Journal (2022), 10.1016/j.cej.2022.137880). Sections were histologically analyzed with HE staining and Masson staining. IL-1β, TNF- α immunohistochemistry was performed, and CD86, CD206, α -SMA immunostaining was performed. HE staining, masson staining, IL-1β, TNF- α analysis were performed according to Image J analysis.

10 Statistical analysis

Data represent three or more independent experiments. Statistical differences were determined by one-way ANOVA analysis and Tukey multiple comparison test. Results are expressed as mean ± Standard Deviation (SD). These differences are considered statistically significant, P < 0.05, P < 0.01, P < 0.001.

Example 1 identification and characterization of 1ABs

The amplified cultured human ADSCs were induced to apoptosis by stimulation with 0.5uM staurosporine (STS) for 12h, and the nuclear membrane was seen to be ruptured under light, many vesicular and bud-like projections were formed on the cell surface, and gradually separated and shed to the cell matrix, ABs (left in FIG. 1A). Then using a sequential centrifugation system, i.e. 300g centrifugation for 10min to remove cells and cell debris pellet, taking supernatant 3000g centrifugation for 10min to obtain ABs pellet, and re-suspending with PBS to obtain ABs suspension. We confirmed the morphology and size of the newly isolated ABs using Transmission Electron Microscope (TEM) observation (right in fig. 1A).

To further confirm the purity of ABs produced by apoptotic ADSCs, western blot analysis showed ABs to express the usual high levels of apoptosis-related markers C3B, C1QC, H3.3, H2B and β -actin as reference proteins, and ADSCs used as controls showed no expression of these apoptosis-related markers (fig. 1B).

ABs was demonstrated to have higher yields, i.e., 1X 10, using protein concentration analysis (BCA) ⁷ Protein concentration of ABs obtained from ADSCs and 1×10 ⁷ The protein concentration of each ADSCs was 57.+ -. 6.25. Mu.g/mL, 115.+ -. 11.14. Mu.g/mL, respectively (FIG. 1C).

The zeta potential and diameter distribution of ABs and ADSCs were further analyzed. As shown in FIG. 1D, the absolute value of the ABs surface potential was reduced to-5.63.+ -. 0.71mV compared to-11.17.+ -. 1.607mV for ADSCs. In fig. 1E, particle size analysis of dynamic light scattering (Dynamic Light Scattering, DLS) shows that the ABs amphiphilic polymer obtained by sequential centrifugation can self-assemble in an aqueous phase system to form vesicles with particle size of about 772.45nm, and the particle size ranges from 531nm to 1110nm.

Example 2 characterization of GelMA hydrogel microspheres loaded with ABs

The GelMA hydrogel microsphere is prepared by adopting a microfluidics technology, the diameter is 190+/-35 mu m, and the porosity is 63+/-6%. It can be seen from the uncrosslinked hydrogel microsphere droplets that the prepared microspheres were uniform in size (fig. 1F). The freeze-dried microspheres formed microspheres with internal porous structure by evaporation of water, which is critical to the physisorption loading of ABs, we observed the porous and ABs loading of hydrogel microspheres by SEM (fig. 1G). Subsequently, microspheres were prepared by GFP-stained GelMA, loaded into hydrogel microspheres with Dil-stained ABs packets, and the appearance of the hydrogel microspheres and ABs loading were observed by fluorescence microscopy (fig. 1H and 1I). As shown in fig. 1J and 2M, hydrogel microspheres slowly degraded in Simulated Body Fluid (SBF) over time, and ABs achieved slow release in SBF (fig. 1J and 1K).

It is also important for the ABs loaded hydrogel microspheres to have adequate sustained release behavior because ABs requires at least > 3 days of localized residence to exert its anti-inflammatory effect. Current ABs studies mostly involve direct injection ABs or nanoparticle fabrication to act on the target site. This approach requires multiple applications of apoptotic bodies, and localized oedema and fluid exudation from the wound can result in loss of valuable apoptotic vesicles, resulting in the inability of apoptotic vesicles to maintain therapeutic concentrations locally for long periods of time. Therefore, we studied the release behavior of GelMA microspheres loaded with different concentrations ABs in body fluids in vitro for 7 days, and examined the released protein concentration by BCA enzyme-labeling method, and plotted the release curve. The plotted release profile shows that an effective sustained release is achieved within 7 days (fig. 2L). On the first day, the GelMA microsphere system with different concentrations ABs released 24.19%, 27.21% and 28.17% of the total amount on average. There was a relatively uniform release every day from day two to day seven, with no significant difference in release behavior at different concentrations. Thus, they can all be considered as effective continuous drug delivery systems. Based on these results, we selected hydrogel microspheres prepared by loading ABs (2 mg ml-1) into GelMA solution (5 wt%) for subsequent study.

The elemental energy spectrum analysis showed that the main element in the GelMA microsphere was C, N, O, while the main element in the ABs loaded GelMA microsphere included C, N, O, P, S. Wherein the P and S elements should be introduced after addition of cell vesicles, which demonstrates successful loading of apoptotic bodies into GelMA microspheres (fig. 2M and 2N).

Example 3 biocompatibility detection

Biocompatibility is a prerequisite for the functioning of biological materials. Thus, in this example, the biocompatibility test was performed to investigate the effect of the material on cytotoxicity and proliferation behavior.

First, the cytotoxicity of ABs was studied by CCK-8 experiments. HUVECs were inoculated into 96-well plates for 12h, respectively (FIG. 2A). The CCK-8 experiment revealed that medium replacement of the original medium at different concentrations (0, 0.5, 1, 1.5, 2 and 2.5. Mu.g/mL) of ABs induced cell activity of HUVECs in 96-well plates after 12 hours, 1 day, 2 days and 3 days, respectively, and that treatment of cells with CCK-8 solution for 1 hour, measurement of OD values at 450nm with a microplate reader indicated that cell viability was highest at 1. Mu.g/mL and that cell viability was slightly decreased at ABs concentrations greater than 1. Mu.g/mL, but did not have statistical differences, indicating that ABs at various concentrations was not cytotoxic and was available for subsequent cell experiments (FIG. 2B). Next, we inoculated HUVECs in 24-well plates and divided them into four groups, and after cell culture for 12 hours, when the activity was stabilized, the cells were cultured with PBS, the leachate of GelMA microsphere, ABs and the leachate of abs@gelma microsphere for 3 days, respectively, treated with live/dead cell staining kit for 30min on day 1 and day 3, and examined for fluorescence by fluorescence microscope (PCOM, nikon, japan). From the live/dead staining results, after 1 and 3 days of culture, most of the cultured cells were observed under the mirror to be live, while few dead cells were observed, indicating that abs@gelma@ms biomaterial had good biocompatibility (fig. 2C).

EXAMPLE 4 macrophage phagocytosis ABs Process characterization

Induction of apoptosis in adipose-derived stem cells resulted in the production of ABs, ABs, which is rich in DNA, RNA, proteins and organelles. Since ABs contains a range of components, they are believed to contribute to the therapeutic effects of ADSCs after implantation. Furthermore, once apoptosis occurs, the apoptosis signal is rapidly transmitted to phagocytes, resulting in immediate clearance of apoptotic cells and debris. Macrophages are specialized phagocytes responsible for eliminating apoptotic debris. They are also important immune cells, critical for inflammation and tissue repair. Thus, we hypothesize that macrophages are the main target cells of ABs. This study shows that macrophages are critical in mediating intercellular interactions after stem cell transplantation and also in activating the inflammatory regulatory capacity of ADSCs. Such cell vesicles, when engulfed by macrophages, cause anti-inflammatory polarization of the macrophages and secrete a range of cytokines that promote healing, including PDGF that promote angiogenesis (fig. 3A). We analyzed and explored phagocytosis of ABs by macrophages at the cellular level using fluorescence microscopy. As shown in fig. 3B, at 0 and 2 hours, the nuclei of Hoechst-stained macrophages had not phagocytized Dil-stained ABs, whereas at 4 hours, red fluorescence was found to be encapsulated within the cells, meaning that the macrophages had phagocytosed ABs.

Example 5ABs verification of endothelial cell migration

Unlike LPS-stimulated macrophage secretions, ABs-stimulated macrophage secretions exhibited a strong effect on migration of HUVECs, with migration areas of 32.26±11.19% and 29.10±4.86% for the control and LPS groups, respectively, after 2 days of culture. The LPS+ ABs group had a migration area (59.36.+ -. 2.97%), showing a 1.84-fold higher relative cell migration area than the control group and a 2.03-fold higher migration area than the LPS group (FIGS. 3C and D). The difference in migration area was more pronounced for HUVECs from group 3, control group 69.55 + -2.43, LPS group 56.31 + -4.32, and LPS+ ABs group 76.28+ -2.65. ABs stimulated macrophage secretions were shown to contain substances that promote migration of HUVECs.

Example 6ABs polarization Effect of ABs and LPS on macrophages

Add 5X 10 to 6 well plates ⁵ THP-1 cells were cultured in RPMI-1640 medium containing 200nM PMA for 48 hours, then washed with PBS 3 times, control group (Control group) was re-added with RPMI-1640 medium, LPS group and LPS+ ABs group were re-added with RPMI-1640 medium containing 100ng/mL LPS, after 48 hours of stimulation, washed with PBS 3 times, control group and LPS group were re-added with RPMI-1640 medium, LPS+ ABs group was re-added with RPMI-1640 medium containing 1ug/mL ABs, and after 48 hours of stimulation. The cytoskeleton of macrophages was stained with Actin-Tracker Green, the nuclei were stained with DAPI, the morphology of macrophages was observed under a fluorescence microscope, the cell morphology of THP-1 cells was observed on day 1, and after stimulation of THP-1 cells with PMA for 48 hours, the change in cell morphology of THP-1 cells towards M0 macrophages was examined, after which M0 cells were treated with LPS and lps+ ABs for 48 hours, respectively, the morphology change of cells was observed (fig. 4A), and after statistics of cell length, THP-1 cells were found to be spherical, whereas after polarization to M0 macrophages, the cell wall flattened, forming a purse egg, but without significant change in diameter, whereas after stimulation with LPS and lps+ ABs, the cell morphology was significantly changed, after LPS treatment, the inflammatory polarization of cells was examined, presenting M1 macrophage-like multi-antenna morphology, whereas after LPS treatment, again after treatment with ABs, the macrophage morphology was transformed towards long spindle M2 macrophage-like morphology (fig. 4B).

mRNA was detected from different groups of cells by RNA-Seq, and in the transcriptome sequencing results, the inflammatory cytokines were up-regulated and anti-inflammatory cytokines were down-regulated in the LPS group relative to the control group, whereas LPS+ ABs group down-regulated inflammatory cytokines and up-regulated anti-inflammatory cytokines compared to the LPS group (FIG. 4C).

Macrophages play a key role in tissue regeneration, and different types of macrophages exhibit spatiotemporal changes following tissue injury to accommodate the requirements of tissue regeneration. The transcriptome sequencing results show that inflammatory factors such as CEMIP2, CX3CR, CXCL11, CXCL9, CCL13 and CCL26 in the LPS group are higher than those in the control group and the ABs group, and the ABs group reduces the up-regulation of the cytokines by inflammatory stimuli. The anti-inflammatory factors such as CSF, IL12B, TNFAIP6, TNFSF10, TNFRSF10B, TNFAIP8, etc. were lower in LPS than in control and ABs groups, while the addition of ABs upregulated the down-regulation of this cytokine by inflammatory stimuli. Furthermore, JAK1 and STAT1 were observed to be significantly higher in macrophages in the LPS group than in the control group, while the addition of ABs down-regulated this change, suggesting that LPS might up-regulate inflammatory response through the JAK1-STAT1 axis, while ABs could down-regulate the JAK1-STAT1 axis to exert anti-inflammatory effects. Arginine belongs to one of the intermediary metabolites of the urea cycle metabolic pathway in the body.

JAK1-STAT1 regulates arginine metabolism, is thought to be an important metabolic regulator regulating macrophage polarization and inflammatory response. The results of this example show that carbamyl phosphate synthase 1 (CPS 1) and argininosuccinate synthase 1 (ASS 1) are significantly higher in the LPS group than in the control group, whereas ABs can down-regulate this enzyme which can cause inflammatory changes. Mechanical studies have shown that rapid and efficient depletion of citrulline by ASS1 is necessary for JAK2-STAT1 signaling and pro-inflammatory cytokine production and serves as a metabolic checkpoint for the innate immune response. Mitochondrial arginase-2 (Arg 2) is critical for reprogramming IL-10 metabolism of inflammatory macrophages, and the results show that Arg2 is significantly higher in the LPS group than in the control group, while ABs can down-regulate Arg2 (fig. 4D).

Previous studies have shown that ASS1 is found to be a pro-inflammatory gene, upregulated in inflammatory macrophages. Rapid and efficient consumption of citrulline by ASS1 is required for JAK2-STAT1 signaling and pro-inflammatory cytokine production, and serves as a metabolic checkpoint of the innate immune response. In this example, it was found that LPS activates ASS1 via the JAK/STAT1 pathway and accelerates urea cycle, resulting in a decrease in ARG1, while ABs could inhibit the up-regulation of this pathway, leading to a shift of polarized macrophages to anti-inflammatory type (FIG. 4E).

EXAMPLE 7ABs anti-inflammatory and pro-healing effects on macrophages

Stimulation of ABs resulted in polarization of macrophages toward M2, and in this study, a flow cytometer was used to evaluate the percentage of M2 macrophages, supporting the inhibition of M2 (CD 11b ⁺ CD206 ⁺ ) The number of macrophages was significantly increased, showing that LPS treatment significantly inhibited CD206 expression compared to untreated macrophages, while the addition of ABs enhanced CD206 expression (fig. 5A and B). RT-qPCR results show that LPS can increase the expression level of JAK1, JAK2, ASS1 and STAT1 in the JAK-STAT pathway, while ABs can decrease the expression level of the JAK-STAT pathway. In addition, the results of RT-qPCR show that the cytokine secreted by the macrophage stimulated by ABs also obviously inhibits the expression of the inflammation-related factor at the transcriptional level, and promotes the expression of the anti-inflammation-related factor. TNF- α and iNOS expression was significantly reduced in ABs, 40.4% and 42.1% compared to control and inflammatory groups, respectively, while TGF-. Beta.1 and IL-10 expression was up-regulated 1.26-fold and 1.72-fold in ABs. (FIG. 5C). Western blot results further supported the anti-inflammatory and pro-healing effects of ABs stimulated macrophages (fig. 5D). The activation of LPS-induced pro-inflammatory macrophages is functionally regulated by JAK-STAT signaling pathways. Notably, the up-regulation of the pathway is inhibited by apoptotic bodies that provide inhibitors of the JAK pathway for THP-1 derived macrophages. Gene knockout by small interfering RNAs (sirnas) also results in reduced expression of the corresponding gene. We found that by siRNA knocking out JAK1, JAK2 and STAT1, expression of JAK1, JAK2 and STAT1 in activated macrophages can be reduced, and that apoptotic bodies have a synergistic effect with this knocking out (fig. 5E).

Example 8 GelMA hydrogel microspheres loaded with ABs induced wound healing in rats diabetes

The distribution of the skin inflammation wound model studies ABs with abs@gelma microspheres in vivo was constructed by creating full thickness wounds in diabetic SD rats.

First, 1 '-octacosyl-3, 3' -tetramethyl-dicarbocyanine, 4-chlorobenzenesulfonate (di) -labeled ABs was subcutaneously injected near the wound on day 1 after surgery, and the di was evaluated by in vivo imaging systems on

days

1, 5, 14 and 21 ⁺ ABs and DiD ⁺ The inflammatory site preservation capacity of the abs@gelma microspheres. DiD (digital information distribution) ⁺ The group of ABs@GelMA microspheres showed a specific DiD around the wound ⁺ ABs, and longer retention time, showed that GelMA microspheres had a stronger retention effect on ABs at the site of inflammation than naked ABs (fig. 7A).

The healing condition of the wound is observed by photographing through a digital camera, the in-vivo effect of ABs is further studied, and as shown in fig. 6B, 6C and 6D, the wound surface area of the abs@gelma microsphere group is 72.25±2.23%, the wound surface area of the ABs group is 75.4±6.10%, the wound surface area of the GelMA microsphere group is 79.66 ±3.69% and the wound surface area of the control group is 95.28±0.70% on the 3 rd day. After day 7, the non-healing area treated with abs@gelma microspheres was much smaller than that of the control and GelMA groups, with abs@gelma microspheres having a wound area of 59.40±6.62%, ABs group 71.97±6.49%, gelMA microspheres group 77.76±4.15% and control wound area 87.47 ±5.02%. By week 2, the difference between the groups was more evident, the wound surface area of the abs@gelma microsphere group was 30.71±6.80%, the ABs group was 42.43 ±6.00%, the GelMA microsphere group was 34.62±1.86%, and the wound surface area of the control group was 47.63±6.80%. At week 3, the best healing of the abs@gelma group was 18.81±0.70, the control group showed a still larger wound area than the other groups, 34.12±2.75, and 5.09±1.15% and 31.55±0.39% for the abs and GelMA microsphere groups, respectively. Treatment with abs@gelma microspheres significantly reduced scar area by approximately 1.3% (n=3). Although the GelMA microspheres have the effect of promoting wound healing, the wound area of the GelMA microsphere group is not different from that of the control group.

Example 9ABs@GelMA in vivo modulation of inflammation, promotion of collagen deposition and revascularization

The number of wound-related inflammatory factors increases in common wounds driven by chemokines in the local extracellular environment until day 2 and then remains stable until around day 5, whereas diabetic wounds are a class of chronic non-healing wounds, the inflammatory condition often persists longer (Adv Drug Deliv Rev 146 (2019), 267-288,AdvHealthc Mater (2022), e 2200516). As shown in fig. 7A, rats developed a type 1 diabetes model 14 days before constructing the wound model, that is, 14 days after injection of STZ, and then the wound was in an inflammatory stage for about 7 days. On day seven, the concentrations of IL-1β and TNF- α were lower in the ABs@GelMA group and the ABs group than in the control group and the GelMA group (FIG. 7B, FIG. 7C and FIG. 7D). HE results showed that the wound lengths of the abs@gelma group and ABs group were significantly shorter than the control group and GelMA group, the abs@gelma group was the shortest, the control group was the longest (fig. 7E and 7F), the inflammatory cells of the wound in the abs@gelma group were the fewest, the control group was the most, and both GelMA group and ABs group were less than the control group (fig. 7G). The Masson results showed that the collagen of the GelMA group, ABs group and abs@gelma group were all more ordered than the control group and were all more ordered than the control group (fig. 7H and 7I).

Example 1 0abs @ gelma induced polarization of M2 macrophages during wound healing and promoted angiogenesis during wound healing, inflammation throughout the entire healing process, which was strongly affected by macrophage polarity (bio mate 19 (2023), 653-665). M2 macrophages inhibit inflammation and promote tissue regeneration. To further elucidate the acceleration of the wound healing process by the polarization of M2 macrophages by abs@gelma, infiltration and polarization of the wound site macrophages were studied by immunofluorescent staining. CD86 was selected as the surface marker for M1 macrophages, CD206 was selected as the surface marker for all subpopulations of macrophages by the surface marker for M2 macrophages, F4/80. As shown in fig. 8A, the abs@gelma group showed less CD86 positive cell distribution (exhibiting red fluorescence) in the subcutaneous layer of the wound site compared to the other groups. The percentage of M1 macrophages in abs@gelma treated wounds was 34.8% of the control group, also less than GelMA or ABs group (fig. 8D). The abs@gelma group showed a broader distribution of CD206 positive cells (exhibiting orange fluorescence). The percentage of M2 macrophages in abs @ GelMA treated wounds was 2.62 times higher than in the control group, also higher than in GelMA or ABs group (fig. 8E). These results indicate that abs@gelma effectively stimulated macrophage polarization to M2 type in vivo. Angiogenesis is an integral step in the excision phase during the wound healing process. M2 macrophages can stimulate angiogenesis at the wound site by secreting PDGF, promoting proliferation and differentiation of vascular endothelial cells. Newly formed blood vessels in the wound were stained with anti-alpha-SMA antibodies (a typical marker for vascular smooth muscle cells). Immunofluorescent-stained images (fig. 8B and 8C) show angiogenesis in abs@gelma treated wounds. The neovascular density count (fig. 8F) showed significantly higher positive expression of α -SMA in dermis of abs@gelma group, 2.37-fold and 2.16-fold positive expression of α -SMA in control and GelMA groups. Taken together, these results clearly demonstrate that abs@gelma significantly induced a higher degree of M2 macrophage polarization during wound healing and promoted cell proliferation and angiogenesis, which greatly accelerated wound healing (fig. 8G).

Claims

1. Use of apoptotic bodies as active substances for inducing polarization of macrophages.

2. The use according to claim 1, characterized in that said apoptotic bodies modulate the expression of JAK-STAT1 signalling pathway.

3. The use according to claim 1, wherein said apoptotic bodies induce polarization of macrophages towards M2 type.

4. Use according to claim 1, characterized in that it promotes angiogenesis.

5. An application of apoptotic bodies as active substances in preparing medicines for promoting chronic wound healing is provided.

6. An application of apoptotic bodies as active substances in the preparation of medical devices for promoting the healing of chronic wounds.

7. A composition for inducing polarization of macrophages towards M2 type, characterized by comprising apoptotic bodies and by using said apoptotic bodies as active substances.

8. The composition for inducing polarization of macrophages toward M2 type according to claim 7, further comprising a scaffold material selected from one or more of PLA, PLGA, gelMA and metals.

9. A composition for promoting healing of chronic wound, characterized by comprising apoptotic bodies and using the apoptotic bodies as active substances.

10. The composition for promoting healing of chronic wounds according to claim 9, further comprising GelMA, forming a hydrogel.