JP2020080922A - Meniscus regeneration base material - Google Patents

Abstract

To provide a meniscus regeneration base material that can accelerate regeneration of a meniscus by being charged into a defective part of the meniscus in a knee joint in regeneration therapy of the meniscus.SOLUTION: A meniscus regeneration base material that can accelerate the regeneration of a meniscus by being charged into a defective part of the meniscus in a knee joint in regeneration therapy of the meniscus has a laminate in which a sponge layer that consists of a bioabsorbable material having slower decomposition rate than polyglycolide, a nonwoven fabric layer that consists of polyglycolide, and the sponge layer that consists of a bioabsorbable material having slower decomposition rate than polyglycolide are combined and unified in this order. 50% compression stress of the nonwoven fabric layer is 0.5 MPa or more, and the thickness of the nonwoven fabric layer is 2 mm or more, the nonwoven fabric layer has through-holes in a thickness direction near both ends, and threads running through the through-holes are taken outside the laminate.SELECTED DRAWING: Figure 3

Description

The present invention relates to a meniscus regeneration base material capable of promoting regeneration of the meniscus by filling a defect portion of the meniscus of a knee joint in the regeneration treatment of the meniscus.

The meniscus is a cartilage-like tissue within the knee joint. The structure of the knee joint will be described below with reference to FIGS. 1 is a schematic cross-sectional view of the right knee joint taken along a sagittal plane, and FIG. 2 is a schematic cross-sectional view of the right knee joint taken along a transverse cross section. As shown in FIG. 1, the knee joint has a meniscus 1 between a femur 4 and a tibia 5, and cartilage 3 is formed on the side where the femur 4 and the tibia 5 face each other. There is a patella 6 on the front surface of the knee, and an infrapatellar fat pad (IPFP) 2 is below the patella 6. The knee joint is wrapped with a joint capsule 7 and the inside of the joint is filled with synovial fluid 8. As shown in FIG. 2, a pair of menisci 1 are formed so as to face the inside and outside of the knee joint, and the front side and the rear side of the knee joint are thickened.

Degeneration and damage of the meniscus are one of the common conditions with cartilage degeneration in osteoarthritis of knee (OA). It is also reported that excision of the meniscus reduces the cartilage tissue and promotes osteoarthritis of the knee. Since the meniscus is a tissue containing many avascular regions, it has poor self-renewal ability and is difficult to self-repair. Therefore, in surgery, in order to accelerate the healing of the meniscus, in addition to meniscus suture, additional treatments such as growth factor, synovial transplantation, bone marrow stimulation have been performed, but regeneration of the meniscus was insufficient. ..

On the other hand, recent advances in cell engineering technology have made it possible to culture a number of animal cells, including human cells, and research on so-called regenerative medicine that attempts to reconstruct human tissues and organs using these cells. Is progressing rapidly. In regenerative medicine, the point is whether cells can proliferate and differentiate to construct a three-dimensional biological tissue-like structure. For example, a base material is transplanted into a patient's body and cells from surrounding tissues or organs are transplanted. A method of regenerating a tissue or organ by invading into a base material to cause proliferation and differentiation is performed.

As such a substrate for regenerative medicine, it has been proposed to use, for example, a nonwoven fabric made of a bioabsorbable material as disclosed in Patent Document 1. When a non-woven fabric made of a bioabsorbable material is used as a base material for regenerative medicine or a suture reinforcing material, cells invade and proliferate in the voids and tissue is regenerated early. Even in the regenerative treatment of meniscus, it has been attempted to use such a tissue regenerating substrate.
However, actually, there is a problem that the regeneration of the meniscus is not promoted as expected even when the conventional tissue regeneration base material is used.

Japanese Patent Laid-Open No. 05-076586

It is an object of the present invention to provide a meniscus regeneration base material capable of promoting regeneration of the meniscus by filling the defect portion of the meniscus of the knee joint in the meniscus regeneration treatment.

The present invention is a meniscus regeneration base material capable of promoting regeneration of the meniscus by filling the defect portion of the meniscus of the knee joint in the regeneration treatment of meniscus, which has a decomposition rate higher than that of polyglycolide. A sponge layer made of a slow bioabsorbable material, a non-woven fabric layer made of polyglycolide, and a sponge layer made of a bioabsorbable material having a slower decomposition rate than polyglycolide have a laminated body which is compositely integrated in this order, and The 50% compressive stress of the non-woven fabric layer is 0.5 MPa or more, and the thickness of the non-woven fabric layer is 2 mm or more, and the non-woven fabric layer has through holes in the thickness direction near both ends, and the through holes are It is the meniscus regenerated base material in which the thread passed through is outside the laminate.
The present invention is described in detail below.

The present inventors examined the cause of insufficient regeneration of the meniscus when the conventional tissue regeneration substrate was used. At that time, when a conventional tissue regeneration substrate was used, good results were obtained in animal experiments using small animals such as rabbits, but when applied to large animals such as pigs and cows, it was sufficient. Found the fact that the meniscus has not been regenerated. As a result of diligent studies, the present inventors have found that the conventional tissue regeneration substrate lacks in physical strength, which is the reason why sufficient results cannot be obtained in large animals.
The knee joint bears total weight when standing or walking. Especially, in large animals including humans, the impact is extremely large. No matter how well rested after implantation, the implanted meniscus regeneration matrix continues to be under great stress during long-term healing. Further, in the meniscus regeneration, there is a unique problem in the regeneration of the meniscus that the transplanted base material and the cartilage come into contact with each other due to the movement of the knee joint, and the friction causes the surface of the base material to be worn.
It is known that the non-woven fabric constituting the conventional tissue regeneration base material preferably has an average pore diameter of about 5 to 30 μm in order to ensure the invasion of cells. However, even if such a conventional tissue regeneration substrate is excellent in terms of cell invasion, it does not have sufficient mechanical strength and is damaged before the meniscus is regenerated or its surface is abraded. It was thought that the thickness would decrease, and would not be able to serve as a scaffolding material for regenerating a meniscus having a sufficient thickness.

As a result of further intensive studies, the present inventors have found that the upper and lower surfaces (both surfaces) of a non-woven fabric layer (hereinafter, also simply referred to as “non-woven fabric layer”) made of polyglycolide having a 50% compressive stress of 0.5 MPa or more are poly. By providing a sponge layer (hereinafter also simply referred to as “sponge layer”) made of a bioabsorbable material whose decomposition rate is slower than that of glycolide and having a certain thickness or more, a large stress is applied after transplantation. However, the inventors have found that a meniscus having a sufficient thickness can be regenerated while maintaining a sufficient thickness without being damaged or the surface being worn away, and thus the present invention has been completed.

The meniscus regenerated substrate of the present invention comprises a sponge layer made of a bioabsorbable material having a slower decomposition rate than polyglycolide, a non-woven fabric layer made of polyglycolide, and a bioabsorbable material having a slower decomposition rate than polyglycolide. The sponge layer has a laminated body that is compositely integrated in this order.
The non-woven fabric layer serves as a scaffold for cell proliferation that invades from surrounding tissues after transplantation, has a role of promoting regeneration of the meniscus, and a role of exhibiting sufficient mechanical strength when stress is applied after transplantation. Further, the sponge layer imparts appropriate flexibility to the meniscus regenerated base material, and when the base material and the cartilage come into contact with each other by the movement of the knee joint after the transplantation and a frictional force is generated, the base material of the base material is regenerated. It has a role of preventing the surface from being worn.

The non-woven fabric layer has a 50% compressive stress of 0.5 MPa or more. Since the non-woven fabric layer has a 50% compressive stress of 0.5 MPa or more, it is possible to regenerate a meniscus having a sufficient thickness without damaging the meniscus regenerating substrate even when a large stress is applied after transplantation. it can. The 50% compressive stress of the non-woven fabric layer is preferably 0.8 MPa or more, and more preferably 1.0 MPa or more. The upper limit of the 50% compressive stress of the non-woven fabric layer is not particularly limited, but the preferable upper limit is 8.0 MPa because the regeneration of the meniscus structure can be further promoted.
The 50% compressive stress can be measured by a method according to JIS-K6767.

The non-woven fabric forming the non-woven fabric layer preferably has a density of 300 mg/cm ³ or more. When the density of the non-woven fabric is 300 mg/cm ³ or more, it becomes easy to adjust the 50% compressive stress of the non-woven fabric layer to 0.5 MPa or more. The density of the non-woven fabric is more preferably 350 mg/m ² or more, further preferably 400 mg/m ² or more. The upper limit of the density of the non-woven fabric is not particularly limited, but the preferable upper limit is 500 mg/cm ³ because regeneration of the meniscus tissue can be further promoted.

The average fiber diameter of the non-woven fabric forming the non-woven fabric layer is not particularly limited, but the preferred lower limit is 25 denier and the preferred upper limit is 40 denier. When the average fiber diameter of the non-woven fabric forming the non-woven fabric layer is within this range, it becomes easy to adjust the 50% compressive stress of the non-woven fabric layer to 0.5 MPa or more. The more preferable lower limit of the average fiber diameter of the non-woven fabric constituting the non-woven fabric layer is 30 denier, and the more preferable upper limit thereof is 32 denier.

The non-woven fabric layer has a thickness of 2 mm or more. By setting the thickness of the nonwoven fabric layer to 2 mm or more, a meniscus having a sufficient thickness can be regenerated. The thickness of the non-woven fabric layer is preferably 4 mm or more. The upper limit of the thickness of the non-woven fabric is not particularly limited, but in practice, the upper limit is substantially 10 mm.

The non-woven fabric layer is made of polyglycolide.
As described above, the nonwoven fabric layer has a 50% compressive stress of 0.5 MPa or more. In order to achieve such a high 50% compressive stress, the nonwoven fabric layer must have an extremely dense structure. According to the common general technical knowledge so far, the average pore diameter of the non-woven fabric constituting the tissue regeneration base material is preferably about 5 to 30 μm in order to ensure the invasion of cells. However, in such a low-density nonwoven fabric, the 50% compressive stress cannot be 0.5 MPa or more. However, surprisingly, the non-woven fabric layer made of polyglycolide has a very dense structure in which 50% compressive stress is 0.5 MPa or more, which is conventionally difficult for cells to invade. You can fully regenerate the meniscus.
When polyglycolide is made into a fibrous form and immersed in physiological saline at 37° C., it takes about 14 days until the tensile strength becomes half that before the immersion. By having such degradability, cells can invade and proliferate as the decomposition and absorption proceed gradually even if the structure is extremely dense so that the 50% compressive stress becomes 0.5 MPa or more, and the nonwoven fabric layer It is considered that a regenerated tissue is built up to the inside, and as a result, a good quality regenerated tissue is constructed. Furthermore, since the cells of the inflammatory system disappear within a few days after being implanted in the living body, it is possible to exert an excellent effect that it is less likely to cause tissue adhesion.

In the present specification, polyglycolide means a polymer of glycolide such as polyglycolic acid, but other bioabsorbable substances such as lactide, ε-caprolactone, p-dioxanone, etc. within a range that does not impair the effects of the present invention. It may be a copolymer with the component. Further, a mixture with another bioabsorbable material such as polylactide may be used as long as the effect of the present invention is not impaired.
When the polyglycolide is a copolymer with other bioabsorbable components such as lactide, ε-caprolactone and p-dioxanone, the preferable lower limit of the amount of the glycolide component in the copolymer is 60 mol %. .. By setting the amount of the glycolide component to be 60 mol% or more, the excellent effect of the present invention that cell penetration is excellent and normal tissue regeneration is performed can be particularly exerted.
When a mixture of the above polyglycolide and another bioabsorbable material such as polylactide is used, the preferable lower limit of the blending amount of polyglycolide in the mixture is 50 mol %. By setting the blending amount of polyglycolide to 50 mol% or more, the excellent effect of the present invention that cell penetration is excellent and normal tissue regeneration is performed can be particularly exerted.

The preferable lower limit of the weight average molecular weight of the polyglycolide is 30,000, and the preferable upper limit thereof is 600,000. If the weight average molecular weight of the polyglycolide is less than 30,000, the strength may be insufficient and a 50% compressive stress of 0.5 MPa or more may not be obtained, and if it exceeds 600,000, the decomposition rate in vivo becomes slow, May cause foreign body reaction. The more preferable lower limit of the weight average molecular weight of the polyglycolide is 50,000, and the more preferable upper limit thereof is 400000.

The melt flow rate may be used as an alternative index of the molecular weight of the polyglycolide. The preferable lower limit of the melt flow rate of the polyglycolide is 0.1 g/10 minutes, and the preferable upper limit thereof is 100 g/10 minutes. Within this range, it becomes easy to produce a nonwoven fabric made of polyglycolide. The more preferable lower limit of the melt flow rate of polyglycolide is 1 g/10 minutes, and the more preferable upper limit thereof is 50 g/10 minutes.
The melt flow rate measurement condition means a value measured under the condition of a load of 4 kgf after polyglycolide was held in the cylinder at 240° C. for 10 minutes to be melted.

The method for preparing the non-woven fabric layer is not particularly limited, and examples thereof include electrospinning deposition method, melt blow method, needle punch method, spun bond method, flash spinning method, hydroentangling method, airlaid method, thermal bond method, resin bond method. A conventionally known method such as a wet method can be used.
However, in the case of a non-woven fabric manufactured by a normal manufacturing method, it may be difficult to set the 50% compressive stress of the non-woven fabric layer to 0.5 MPa or more. In such a case, the 50% compressive stress can be adjusted to 0.5 MPa or more by laminating a plurality of non-woven fabrics to form a composite and then compressing by a method such as hot pressing.
Furthermore, if necessary, it is preferable that the compressed nonwoven fabric is sewn with a thread made of a bioabsorbable material. The compressed non-woven fabric is subjected to a stress of returning to the original thickness, but by fixing the thickness by applying a sewing machine, it is possible to prevent the density from decreasing. The sewing pitch is not particularly limited, but a pitch of 5 mm or less is preferable in order to reliably fix the thickness.

The nonwoven fabric layer has through holes in the thickness direction near both ends.
By providing through holes in the thickness direction near both ends of the non-woven fabric layer and passing a thread described later through the through holes, the meniscus regenerated substrate can be easily fixed during transplantation.
When the meniscus regeneration base material is transplanted into the body, it is necessary to use a thread to fix the meniscus regeneration base material and the tibia in order to prevent the meniscus regeneration base material from being displaced by the movement of the foot or the like. However, with the conventional meniscus regenerated substrate, there is a problem that it is difficult to fix the meniscus regenerated substrate while maintaining it at the position where it is desired to be transplanted. The meniscus regenerated base material of the present invention has through holes near both ends of the non-woven fabric layer, and since the thread is passed therethrough, it is not necessary to tie and fix the meniscus regenerated base side at the time of transplantation, and the tibial side Since the fixation is completed simply by tying only the parts, transplantation can be performed easily and in a short time.
It is preferable to provide two or more through-holes at each end because the meniscus regenerated substrate can be fixed more reliably. Here, the thickness direction means a direction perpendicular to a plane in which the cross section of the meniscus regenerated substrate is half-moon shaped. The term “near both ends” as used herein means both ends of the above-mentioned non-woven fabric layer which are not in direct contact with other tissues such as cartilage when transplanted into the body. Further, the diameter of the through hole is appropriately adjusted according to the diameter of the yarn described later.

In the meniscus recycled substrate of the present invention, the thread that has passed through the through hole is exposed to the outside of the laminate.
By having the thread that has passed through the through-hole to the outside of the laminate, when fixing the meniscus regenerated base material to the tibia during transplantation, the meniscus regenerated base material can be fixed simply by tying only the tibia side. The transplantation can be performed easily and in a short time.

The yarn is not particularly limited, and may be a monofilament yarn, a multifilament yarn, or a braid made by braiding a plurality of yarns. Of these, braids are preferable because they are excellent in strength and handleability.

The above-mentioned thread may pass through both sponge layers to the outside, or may go out between the sponge layers and the non-woven fabric layer, and when the sponge layers are not formed at both ends of the non-woven fabric layer. May go out directly from the nonwoven fabric layer. Above all, since it is possible to improve the slippage of the meniscus regenerated base material, and because the thread is more easily tied by being fixed by the sponge layer, the above-mentioned thread is externally attached between each sponge layer and the non-woven fabric layer. It is preferable to go out.

The material of the thread is not particularly limited, and materials such as polypropyne, nylon, polyethylene, polyvinylidene fluoride, and polytetrafluoroethylene that are commonly used for sewing clothing can be used as they are. However, in consideration of safety, a bioabsorbable material is preferable. Examples of the bioabsorbable material include polyglycolide, polylactide, poly-ε-caprolactone, lactide-glycolic acid copolymer, glycolide-ε-caprolactone copolymer, lactide-ε-caprolactone copolymer, polycitric acid, Polymalic acid, poly-α-cyanoacrylate, poly-β-hydroxy acid, polytrimethylene oxalate, polytetramethylene oxalate, polyorthoester, polyorthocarbonate, polyethylene carbonate, poly-γ-benzyl-L-glutamate, Synthetic polymers such as poly-γ-methyl-L-glutamate, poly-L-alanine and polyglycol sebastic acid, polysaccharides such as starch, alginic acid, hyaluronic acid, chitin, pectic acid and its derivatives, gelatin, Examples thereof include natural polymers such as proteins such as collagen, albumin and fibrin.

The preferred lower limit of the weight average molecular weight of the bioabsorbable material is 10,000, and the preferred upper limit is 400,000. When the weight average molecular weight of the bioabsorbable material is at least the above lower limit, a yarn having more excellent tensile strength can be obtained, and the meniscus regenerated substrate is surely not decomposed until the meniscus is regenerated. Can be fixed. When the weight average molecular weight of the bioabsorbable material is equal to or less than the upper limit, foreign body reaction can be suppressed. The more preferable lower limit of the weight average molecular weight of the bioabsorbable material is 20,000, and the more preferable upper limit thereof is 250,000.

The yarn preferably has a diameter of 0.1 to 1 mm. When the diameter of the yarn is within the above range, the yarn has excellent tensile strength and knot strength, and can be easily fixed. The more preferable lower limit of the diameter of the yarn is 0.3 mm, and the more preferable upper limit thereof is 0.8 mm.

The yarn preferably has a tensile strength of 20N to 200N.
When the tensile strength of the yarn is within the above range, the meniscus regenerated base material can be reliably fixed until the meniscus is regenerated. The more preferable lower limit of the strength of the yarn is 40 N, the further preferable strength is 60 N, the more preferable upper limit is 180 N, and the still more preferable upper limit is 150 N.

The material forming the sponge layer is not particularly limited as long as it is a bioabsorbable material having a slower decomposition rate than polyglycolide, but is preferably a lactide-ε-caprolactone copolymer. By using a lactide-ε-caprolactone copolymer having excellent flexibility and abrasion resistance in the sponge layer, it is possible to impart appropriate flexibility to the meniscus regenerated base material of the present invention, and the base material. When the cartilage and the cartilage come into contact with each other due to the movement of the knee joint to generate a frictional force, it is possible to make the surface of the base material less likely to wear.

The density of the sponge layer is not particularly limited, but the preferred lower limit is 40 mg/cm ³ and the preferred upper limit is 120 mg/cm ³ . When the density of the sponge layer is within this range, sufficient flexibility and abrasion resistance can be exhibited. A more preferable lower limit of the density of the sponge layer is 70 mg/cm ³ , and a more preferable upper limit thereof is 90 mg/cm ³ .

The thickness of the sponge layer is not particularly limited, but the preferred lower limit is 0.1 mm and the preferred upper limit is 1.0 mm. When the thickness of the sponge layer is within this range, the surface of the base material is prevented from being worn when the base material and the cartilage come into contact with each other due to the movement of the knee joint after the transplantation and a frictional force is generated. Can play a sufficient role.

The method for preparing the sponge layer is not particularly limited, and a conventionally known method such as freeze-drying a solution obtained by dissolving the bioabsorbable material in a suitable solvent and then freeze-drying can be used.

The recycled meniscus substrate of the present invention has one or both surfaces of a laminate comprising a sponge layer/nonwoven fabric layer/sponge layer as the outermost layer for the purpose of imparting slipperiness and further exhibiting abrasion resistance. It may have a film layer made of a lactide-ε-caprolactone copolymer.
In addition, in the present specification, the film means a thin film-like body which does not have at least μm-order pores which can be observed by an optical microscope.

The film layer may contain a lubricant for the purpose of further improving the slipperiness as long as the medical use is not impaired.

The thickness of the film layer is not particularly limited, but the preferred lower limit is 0.1 mm and the preferred upper limit is 0.3 mm. If the thickness of the film layer is less than 0.1 mm, it may not be possible to sufficiently prevent the surface of the base material from being abraded by friction due to contact with cartilage after transplantation, and if it exceeds 0.3 mm. , May be inferior in handleability.

The sponge layer and the non-woven fabric layer (and the film layer) are compositely integrated.
If the above layers are not compositely integrated, some or all of the above layers may peel off when the meniscus regenerating substrate of the present invention is transplanted. If even a part of each of the layers is peeled off, a cell pool may be generated in the space formed in the peeled part, and a normal tissue or organ may not be regenerated.
In the present specification, the term “combined and integrated” means that the sponge layer and the non-woven fabric layer (and the film layer) are laminated with an adhesive force such that they cannot be separated from each other by pulling them by hand.

The meniscus regenerated base material of the present invention is subjected to a repeated compression test in which a load of 300 N is repeatedly applied 20 times to warm water of 37° C. to a meniscus regenerated base material having a length of 20 mm and a width of 20 mm. It is preferable that the maintenance ratio of the thickness of the meniscus recycled substrate is 95% or more. Thereby, even if a large stress is repeatedly applied after transplantation, the meniscus regenerating base material can maintain a sufficient thickness, and the meniscus having a sufficient thickness can be regenerated. The maintenance ratio of the thickness is more preferably 98% or more, further preferably 100%.
The above-mentioned thickness maintenance rate means the ratio (%) of the thickness of the meniscus regenerated substrate after the repeated compression test to the thickness of the meniscus regenerated substrate before the repeated compression test.

Here, a schematic view and a sectional view of the meniscus regenerated substrate of the present invention are shown in FIGS.
3 and 4 show a mode in which the yarn is exposed to the outside from between the nonwoven fabric layer and the sponge layer. As shown in FIGS. 3 and 4, the meniscus regenerated substrate of the present invention has a nonwoven fabric layer 9 having through holes in the thickness direction near both ends, a sponge layer 10, and a thread 11 passing through the through holes. The sponge layer 10, the threaded non-woven fabric layer 9, and the sponge layer 10 are compositely integrated in this order. Further, the sponge layer 10 is formed so as to cover not only the non-woven fabric layer 9 but also the yarn 11, and the yarn 11 is exposed to the outside from between the non-woven fabric layer 9 and the sponge layer 10. By forming the sponge layer 10 so as to cover the thread 11, it is possible to prevent the thread 11 from being caught in the vicinity of the through hole, and to prevent the thread 11 from slipping so that the thread 11 can be easily tied. The meniscus regeneration base material of the present invention is implanted in the body by fixing the threads 11 at both ends to the tibia.

The method for producing the meniscus recycled substrate of the present invention is not particularly limited, and for example, after separately preparing the non-woven fabric layer having the through hole and the thread passing through the through hole, the sponge layer (and the film layer), Examples of the method include a method of laminating with a medical adhesive, a method of dissolving a part of the surface of each layer with a solvent and then laminating.

According to the present invention, it is possible to provide a meniscus regeneration base material capable of promoting regeneration of the meniscus by filling a defect portion of the meniscus of the knee joint in the regeneration treatment of the meniscus.

It is a cross-sectional schematic diagram in the sagittal plane of the right knee joint. It is a cross-sectional schematic diagram in the cross section of a right knee joint. It is a schematic diagram showing an example of the meniscus regenerated substrate of the present invention. It is sectional drawing showing an example of the meniscus regenerated base material of this invention. 3 is a nuclear magnetic resonance image (MRI) 0, 4, and 8 weeks after transplantation of the meniscus regenerated substrate obtained in Example 1 into a pig meniscus removal part. 3 is a hematoxylin-eosin-stained image of the transplanted portion 8 weeks after transplantation of the meniscus regenerated substrate obtained in Example 1 to a pig's meniscus-removed portion. 8 is a safranin staining of a transplanted portion at 8 weeks after transplantation of the meniscus regenerated substrate obtained in Example 1 to a pig meniscus removed portion.

Hereinafter, the embodiments of the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

(Example 1)
(1) Preparation of Nonwoven Fabric Layer Polyglycolide having a weight average molecular weight of 250,000 is used as a bioabsorbable material, and a fabric made of yarn having an average fiber diameter of 31 denier obtained by spinning this is made into a nonwoven fabric by a needle punch method. Thus, a nonwoven fabric having an average fiber diameter of about 20 μm and a thickness of about 300 μm was obtained.
14 sheets of the obtained non-woven fabric were piled up, and in that state, needle punching was performed from one side to make a composite integrated. Next, the composite-integrated laminate was hot-pressed at a temperature of 100° C. for 1 minute, and then sewn with a 5 mm pitch using a 400 denier thread made of polyglycolide. Then, the laminate was cut into a meniscus shape, and two through holes were formed in both ends in the thickness direction to obtain a non-woven fabric layer having a thickness of 3.7 mm. A braid made of polyglycolic acid thread was passed through the through hole.

The 50% compressive stress of the obtained nonwoven fabric layer was 3.5 MPa as measured by the method according to JIS-K6767. The density of the obtained nonwoven fabric layer was 400 mg/cm ³ .

(2) Preparation of sponge layer L-lactide-ε-caprolactone copolymer (molar ratio 50:50, weight average molecular weight 200,000) was dissolved in dioxane to prepare a 4% by weight dioxane solution. The non-woven fabric layer in which the thread was passed was allowed to stand in the glass petri dish, and the obtained solution was poured into the glass petri dish so that the height of the liquid surface was almost equal to the height of the non-woven fabric layer. After freezing at -80°C for 1 hour, using a freeze dryer (ADVANTEC, DRZ350WA), freeze-drying at -40°C for 12 hours to form a sponge layer having a thickness of about 100 µm on both surfaces of the nonwoven fabric layer. Then, a laminated body was obtained in which the sponge layer/nonwoven fabric layer through which the thread was passed/sponge layer was integrally laminated. The sponge layer was formed so as to cover the nonwoven fabric layer, the through holes, and the threads on the nonwoven fabric layer.

(3) Production of meniscus regenerated substrate An L-lactide-ε-caprolactone copolymer (molar ratio 50:50, weight average molecular weight 400,000) was dissolved in dioxane to prepare a 4% by weight dioxane solution. The obtained solution was poured into a glass petri dish, air-dried and heat-treated to obtain a film having a thickness of about 100 μm.
A small amount of dioxane is applied to the surface of one side of the obtained film to partially dissolve it, and the sponge layer/threaded non-woven fabric layer/sponge layer are laminated and integrated on the upper and lower surfaces (both surfaces). The film is laminated on the sponge layer so that the film is in contact with the sponge layer, and the film and the laminated body are combined and dried to form a film layer having a thickness of about 100 μm, and the film layer/sponge layer/threaded non-woven fabric layer is formed. A meniscus regenerated base material was obtained which was composed of a laminated body in which the /sponge layer/film layer was laminated and integrated. The 50% compressive stress of the obtained meniscus regenerated substrate was 3.8 MPa as measured by the method according to JIS-K6767.

The meniscus recycled substrate was cut into a size of 20 mm in length and 20 mm in width to obtain a sample. The obtained sample was immersed in warm water at a temperature of 37° C., and a load of 300 N was repeatedly applied 20 times to perform a repeated compression test. The thickness of the meniscus regenerated base material before the repeated compression test and the thickness of the meniscus regenerated base material after the repeated compression test were measured, and the thickness retention ratio was calculated to be 100%.

<Evaluation by animal experiment>
A large animal pig was prepared as an experimental animal, and the anterior segment of the medial meniscus of the right knee joint was excised. The meniscus regenerated substrate obtained in the example was transplanted and sutured to the meniscus removal part.
Nuclear magnetic resonance images (MRI) of the right knee joint were taken 0, 4, and 8 weeks after the operation. The taken nuclear magnetic resonance image (MRI) is shown in FIG.
In addition, 8 weeks after the operation, the animals were sacrificed, the medial meniscus of the right knee joint was taken out, and the transplanted portion was extracted. The obtained specimens were stained with hematoxylin-eosin and stained with safranin, and micrograph images are shown in FIGS. 6 and 7.
From FIG. 5, it can be seen that the cartilage is regenerated from the part corresponding to the joint. Further, from FIGS. 6 and 7, regeneration of cartilage tissue (a portion stained red in the stained image in FIG. 7) was observed in the portion transplanted with the meniscus regeneration substrate 8 weeks after the operation.

<Evaluation of portability>
The ease of transplantation of the meniscus regenerated substrate obtained in Example 1 was evaluated using pigs. The meniscus regenerating base material of Example 1 could be fixed simply by passing a thread through the hole opened in the tibia and ligating it in a short time. In the case of a conventional meniscus regenerated base material without a thread, after passing a suture thread with a needle through a hole opened in the tibia, it is necessary to further suture the meniscus regenerated base material, It takes time to transplant.

According to the present invention, it is possible to provide a meniscus regeneration base material capable of promoting regeneration of the meniscus by filling a defect portion of the meniscus of the knee joint in the regeneration treatment of the meniscus.

1 meniscus 2 subpatellar fat pad 3 cartilage 4 femur 5 tibia 6 patella 7 joint capsule 8 synovial fluid 9 non-woven fabric layer 10 sponge layer 11 thread

Claims (6)

In a meniscus regeneration treatment, a meniscus regeneration base material capable of promoting regeneration of the meniscus by filling a defect portion of the meniscus of a knee joint,
A layer in which a sponge layer made of a bioabsorbable material whose decomposition rate is slower than that of polyglycolide, a non-woven fabric layer made of polyglycolide, and a sponge layer made of a bioabsorbable material whose decomposition rate is slower than polyglycolide are combined and integrated in this order. Have a body,
50% compressive stress of the non-woven fabric layer is 0.5 MPa or more, and the thickness of the non-woven fabric layer is 2 mm or more,
The meniscus regenerated base material, wherein the non-woven fabric layer has through holes in the thickness direction near both ends, and the thread passing through the through holes is exposed to the outside of the laminate. The meniscus regenerating substrate according to claim 1, wherein the sponge layer is made of a lactide-ε-caprolactone copolymer. ^3. The meniscus recycled substrate according to claim 1, wherein the density of the non-woven fabric forming the non-woven fabric layer is 300 mg/cm ³ or more. The meniscus regenerated substrate according to claim 1, 2 or 3, wherein the nonwoven fabric constituting the nonwoven fabric layer has an average fiber diameter of 25 to 40 denier. The meniscus regenerating substrate according to claim 1, 2, 3 or 4, which has a film layer made of a lactide-ε-caprolactone copolymer on one or both surfaces. The retention rate of the thickness of the meniscus regenerated base material after a repeated compression test in which a load of 300 N is repeatedly applied 20 times in warm water of 37° C. to a meniscus regenerated base material of 20 mm length and 20 mm width. Is 95% or more, The meniscus regenerated substrate according to claim 1, 2, 3, 4 or 5.

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