CN114557318B - Construction method and application of non-alcoholic steatohepatitis mouse model based on PEDF/LDLR double gene knockout - Google Patents

Abstract

The invention discloses a construction method and application of a non-alcoholic steatohepatitis mouse model based on PEDF/LDLR double gene knockout, and belongs to the technical field of medicines. The invention adopts high-fat diet to induce PEDF/LDLR double-gene knockout mice to generate non-alcoholic steatohepatitis phenotype, and the constructed animal model shows the characteristics of obesity, hyperlipidemia, insulin resistance, hyperglycemia, liver steatosis, liver inflammatory reaction, liver fibrosis, liver tumor, cardiovascular injury and the like, and can be used for preclinical research of research and development of metabolic diseases such as non-alcoholic steatohepatitis and the like. The animal model construction method is simple and feasible, and can be widely popularized. The model can better simulate the pathogenesis characteristics, the lesion progress and the lesion characteristics of each stage of human NASH and can embody the coexistence characteristics of cardiovascular diseases of NASH patients, thereby providing an important tool for preclinical research on medicament development of metabolic diseases such as NASH and the like.

Description

Construction method and application of non-alcoholic steatohepatitis mouse model based on PEDF/LDLR double gene knockout

Technical Field

The invention belongs to the technical field of medicines, and particularly relates to a construction method and application of a non-alcoholic steatohepatitis mouse model based on PEDF/LDLR double gene knockout.

Background

Non-alcoholic fatty liver disease (Nonalcoholic fatty liver disease, NAFLD) is a clinical pathological syndrome characterized by liver cell steatosis and lipid storage without history of excessive alcohol consumption, and has now become a major cause of chronic liver disease worldwide. The pathological changes of the liver cancer show simple fatty liver, nonalcoholic steatohepatitis (Nonalcoholic steatohepatitis, NASH) and liver fibrosis along with the progress of the disease course, and finally, the liver cirrhosis and hepatocellular carcinoma are developed. NASH is an extremely developed form of nonalcoholic fatty liver, defined as the appearance of steatosis with inflammation and hepatocyte damage, characterized by liver steatosis, inflammation, hepatocyte damage and varying degrees of fibrosis. It is counted that the global prevalence of NAFLD is about 25% and is increasing dramatically at a rate of 360 thousand new cases per year. Of these, about 20% of NAFLD patients progress to NASH, and 20% of NASH patients progress to cirrhosis. Thus, the dramatic increase in the incidence of NAFLD and NASH has become a major public health problem worldwide.

NASH has a complex pathological mechanism and an inflammatory response driven by metabolic abnormalities is still considered as a key step in the development of NASH. However, despite the great progress in recent years of research on NASH pathology, there is currently no drug approved by the united states food and drug administration (Food and Drug Administration, FDA) for clinical treatment of NASH, resulting in NASH patients still facing a "drug-free treatable" situation. The most important of preclinical studies is the testing of target rationality and drug formulation by animal trials. Therefore, the key to the success of new drug development is the selection of the correct animal model. NASH drug clinical frustration and preclinical animal data are difficult to translate into clinical results, suggesting that current animal models need improvement. None of the current NASH animal models is able to mimic the pathogenesis of NASH, the course of onset and the pathological features of each stage simultaneously. Of particular concern, current NASH animal models have a common problem in that the inflammatory response is mild and it is difficult to induce a severe liver inflammatory response. The severe liver inflammatory response is precisely a significant sign of NASH as distinguished from simple fatty liver, and it is evident that current animal models of NASH are not conducive to evaluation of preclinical drug effects. In addition, 25% -40% of NASH patients clinically accompany cardiovascular disease, and cardiovascular disease has become a major factor in NASH patient death. There is currently no recognized NASH model that reflects the co-existence of cardiovascular disease in NASH patients. Therefore, establishing a NASH mouse model which is characterized by coexistence of severe liver inflammatory response and cardiovascular diseases has important significance for drug development of NASH.

Disclosure of Invention

In order to solve the technical problems, the invention provides a construction method and application of a non-alcoholic steatohepatitis mouse model based on PEDF/LDLR double gene knockout.

In order to achieve the above purpose, the invention adopts the following technical scheme:

the construction method of the non-alcoholic steatohepatitis mouse model based on PEDF/LDLR double gene knockout is characterized by comprising the following construction steps:

(1) Mating the PEDF gene knockout mouse with the LDLR gene knockout mouse to obtain a PEDF/LDLR double-gene knockout mouse;

(2) And (3) performing high-fat feed induction on the PEDF/LDLR double-gene knockout mice to obtain a non-alcoholic steatohepatitis mouse model.

Furthermore, in the step (1), the PEDF knockout mice and the LDLR knockout mice are both C57BL/6J background.

Further, the nutrient mass ratio of the high-fat feed in the step (2) is as follows: 26.2% of protein, 26.3% of carbohydrate and 34.9% of fat.

The invention also provides application of the method for constructing the non-alcoholic steatohepatitis mouse model in the field of animal model construction.

The invention also provides application of the mouse model constructed by the method for constructing the non-alcoholic steatohepatitis mouse model in screening or treating metabolic diseases.

Further, the metabolic diseases include obesity, hyperlipidemia, insulin resistance, diabetes, simple fatty liver, nonalcoholic steatohepatitis-associated liver fibrosis, nonalcoholic steatoliver-associated liver cancer and nonalcoholic steatohepatitis-associated cardiovascular injury.

Further, the application comprises screening of drug targets, screening of drugs, pharmacodynamics evaluation of drugs and safety evaluation of drugs.

Compared with the prior art, the invention has the following beneficial effects:

the invention adopts high-fat feed induction, which accords with the pathogenesis characteristics of human NASH; simple fatty liver phenotypes such as obesity, hyperlipidemia, insulin resistance, hyperglycemia, liver steatosis and the like occur in the early stage, NASH phenotypes such as liver inflammatory reaction, liver fibrosis and the like occur in the later stage, liver tumors occur at a certain probability, and serious cardiovascular injury is accompanied, especially the liver inflammatory reaction is strong, so that the human NASH pathological change progress and pathological change characteristics are met.

The method is simple and feasible, and can be widely popularized. The model can better simulate the pathogenesis characteristics, the lesion progress and the lesion characteristics of each stage of human NASH, so that the model has important significance for preclinical research on research and development of metabolic diseases such as NASH and the like.

Drawings

FIG. 1 is a graph showing the results of measurement of body weight, blood lipid level, glucose tolerance, insulin resistance, serum insulin level and blood glucose in animals of group 4 in example 1.

FIG. 2 is a graph showing the results of evaluation of liver weight, liver mass ratio, liver function enzyme level, liver steatosis, liver inflammatory response and liver fibrosis in the 4 animals of example 2.

FIG. 3 is a graph showing the results of evaluation of liver weight, liver mass ratio, liver function enzyme level, liver steatosis, liver inflammatory response and liver fibrosis in the 4 animals of example 3.

FIG. 4 is a graph showing the statistics of liver tumor occurrence amount and identification result of tumors in 4 groups of animals in example 4.

FIG. 5 is a graph showing the results of the measurements of the aortic inner diameter, aortic valve blood flow peak, descending branch aortic blood flow peak, aortic plaque area ratio and myocardial cell size of the 4 animals in example 5.

Detailed Description

The following experimental animals and breeds:

PEDF knockout mice were constructed for the C57BL/6J background from the Ma Jianxing professor task group of us Oklahoma University and were friendly given by the professor task group of the university of chinese medical college Gao Guoquan. LDLR knockout mice were in the C57BL/6J background, introduced in the United states Jackson laboratories. PEDF/LDLR double gene knockout mice were obtained from mating PEDF knockout mice and LDLR knockout mice.

The experimental animals used in the invention are all propagated in the center of disease mode animals of university of Zhongshan. The invention selects experimental animals and groups as follows: (1) wild normal group: male 8-week-old wild type C57BL/6J mice, conventional feed induction; (2) wild high-fat group: male 8-week-old wild type C57BL/6J mice, high-fat feed induction; (3) LDLR knockout hyperlipidemic: male 8-week-old LDLR knockout mice, high-fat feed induction; (4) double knock hyperlipoidemia: male 8-week-old PEDF/LDLR double-gene knockout mice, high-fat diet induction. The animals eat with water during the feeding period, alternately illuminate every 12 hours, and the temperature is 18-21 ℃ and the humidity is 50-70%.

Animal serum and tissue material selection:

animals were fasted and not water-inhibited for 12-16 hours prior to sample collection. During sample collection, the mice are weighed, 1% pentobarbital sodium is injected into the abdominal cavity, 80mg/kg, after the mice are anesthetized, eyeballs are taken for blood collection, serum is collected by centrifugation, and then the mice are fixed on an dissecting plate in a supine position, and the surfaces of 75% sterile alcohol are sterilized. The abdominal cavity of the mouse is cut to the thoracic cavity by surgical scissors, the visceral tissues are exposed, the right auricle is cut, PBS is infused into the left ventricle by needle insertion until blood flows completely, the aorta of the ascending branch aorta to the iliac artery branch section is peeled off, liver tissues and/or tumor tissues and/or heart tissues are cut off, and the liver is rinsed in PBS until no blood stain exists and then is weighed.

Pathological tissue treatment:

taking a mouse liver part tissue or a tumor part tissue or a heart part tissue, rinsing in PBS (phosphate buffered saline) until no blood stain exists, and fixing in 4% paraformaldehyde overnight; washing with PBS for 3 times, each for 10 minutes; gradient dehydration is carried out on 25% ethanol, 50% ethanol, 75% ethanol, 90% ethanol, absolute ethanol (I) and absolute ethanol (II) for 30 minutes respectively; xylene (I) and xylene (II) each for 15 minutes; paraffin (I) and paraffin (II) each for 60 minutes; placing the tissues in paraffin for embedding after dehydration; the Leica paraffin wax slicer is used for slicing, and the slice thickness is 5 mu m.

The mouse aorta was taken, rinsed in PBS until no blood stain, fixed overnight in 4% paraformaldehyde, and subsequently the whole aorta was stained with oil red O.

Example 1

This example measures the weight, blood lipid content, glucose tolerance, insulin resistance, serum insulin content and blood glucose of the 4 animals.

The 4 animals were weighed at weeks 0, 16, 32 and 48, respectively, and fasted for 12-16 hours prior to weighing; glucose tolerance test and insulin tolerance test were performed at 32 weeks of induction, and specific procedures were as follows: animals were fasted for 12-16 hours, were intraperitoneally injected with 1g/kg of glucose or 1U/kg of insulin, respectively, and blood glucose was measured at 0, 15, 30, 60, 90, 120 and 180 minutes after injection, and a blood glucose change curve was drawn and the area under the curve was calculated; at 32 weeks and 48 of induction, animals were fasted for 12-16 hours, blood glucose was measured using a glucometer, and serum samples were collected by dissecting the mice and assayed for serum total cholesterol, triglycerides and insulin content using a commercial kit.

The results are shown in FIG. 1, where A: weight of the body; serum total cholesterol content; c: serum total triglyceride content; d: a blood glucose change curve and area under the curve statistics of a glucose tolerance test; e: counting the area under a blood glucose change curve and a curve of an insulin resistance test; f: serum insulin content; g: blood sugar; * P is less than 0.05, vs wild normal group; * P < 0.01, vs wild normal group; * P < 0.001, vs wild normal group; # p < 0.05, vs wild high-fat group; # and p < 0.01, vs wild high-fat group; # #, p < 0.001, vs wild high-fat group; the &, p is less than 0.01, vs LDLR knocks out the high-fat group; and & &, p < 0.001, vs LDLR knocks out the high fat group.

Nonalcoholic steatohepatitis is often accompanied by obesity, dyslipidemia, insulin resistance and hyperglycemia. The results in figure 1 demonstrate that double knockout hyperlipidemic mice exhibit more severe obesity, lipid metabolism disorders, insulin resistance and hyperglycemia relative to LDLR knockout hyperlipidemic mice at 32 weeks and 48 weeks of induction.

Example 2

In this example, the liver weight, the liver body ratio, the liver function enzyme level, the liver steatosis, the liver inflammatory response and the liver fibrosis of the above 4 animals were evaluated at the time of induction for 32 weeks.

At 32 weeks of induction, animals were sacrificed under anesthesia after 12-16 hours of fasted, serum and tissue samples were collected, and liver tissue was weighed; detecting serum glutamic pyruvic transaminase and glutamic oxaloacetic transaminase levels by using a commercial kit; and HE staining and Masson staining were performed on paraffin sections of liver tissue to evaluate liver lesions.

The results are shown in FIG. 2, wherein A is a general picture of the liver; b: liver weight; c: liver mass ratio; d: serum glutamic pyruvic transaminase level; e: serum glutamate oxaloacetic transaminase levels; f: HE staining; g: scoring hepatic steatosis; h: scoring liver balloon-like degeneration; i: scoring inflammation in the liver lobules; j: masson staining; k: scoring liver fibrosis; * P is less than 0.05, vs wild normal group; * P < 0.01, vs wild normal group; * P < 0.001, vs wild normal group; # p < 0.05, vs wild high-fat group; # and p < 0.01, vs wild high-fat group; # #, p < 0.001, vs wild high-fat group; the &, p is less than 0.01, vs LDLR knocks out the high-fat group; and & &, p < 0.001, vs LDLR knocks out the high fat group.

The liver paraffin section HE staining method mainly comprises the following steps: baking at 60 ℃ for 30 min, xylene (I) for 10 min, xylene (II) for 10 min, absolute ethanol (I) for 3 min, absolute ethanol (II) for 3 min, 95% ethanol (I) for 1 min, 70% ethanol for 1 min, distilled water for 2 min, hematoxylin solution for 5-10 min, running water for washing hematoxylin for 1-3 seconds, 1% hydrochloric acid alcohol for 1-2 seconds, running water for 20 min, distilled water for 1-2 seconds, 0.5% eosin for 2 min, distilled water for 1-2 seconds, 95% ethanol (II) for 2-3 seconds, absolute ethanol (III) for 3-5 seconds, absolute ethanol (IV) for 5-10 seconds, xylene (I) for 2 min, xylene (II) for 2 min, and neutral resin sealing sheet.

The liver paraffin section Masson staining method mainly comprises the following steps: baking at 60 ℃ for 30 min, xylene (I) for 10 min, xylene (II) for 10 min, absolute ethanol (I) for 3 min, absolute ethanol (II) for 3 min, 95% ethanol (I) for 1 min, 70% ethanol for 1 min, distilled water for 2 min, weiert's iron hematoxylin for 5 min, running water for washing hematoxylin for 1-3 seconds, 1% hydrochloric acid for 1-2 seconds, running water for 20 min, distilled water for 1-2 seconds, ponceau acid for 5-10 min, distilled water for a few seconds, phosphomolybdic acid water for about 3-5 min, aniline blue for counterstain for 1% glacial acetic acid for 2-3 seconds, absolute ethanol (III) for 3-5 seconds, absolute ethanol (IV) for 5-10 seconds, xylene (I) for 2 min, xylene (II) for 2 min, and observation of a neutral resin seal.

The histological evaluation system was appropriately adapted based on the NASH clinical research network scoring system (NASH-CRN) in the united states. The steatosis scoring criteria were (calculated on the proportion of adipogenic hepatocytes): 0 (< 5%), 1 (5-33%), 2 (> 33-66%), 3 (> 66-80%), 4 (> 80%); the hepatocyte balloon-like variation scoring criteria were: 0 (none), 1 (rare), 2 (most common), 3 (extremely common); the criteria for grading inflammation in the leaflet were (calculated as number and area of inflammatory necrosis lesions under 200-fold mirror): 0 (none), 1 (< 2), 2 (2-4), 3 (> 4), 4 (containing large areas of inflammatory necrosis); the fibrosis scoring criteria were: 0 (none), 1 (Dou Zhou fibrosis or periportal fibrosis), 2 (Dou Zhou fibrosis and periportal fibrosis), 3 (bridging fibrosis), 4 (cirrhosis).

Nonalcoholic steatohepatitis is often accompanied by hepatomegaly, elevated liver function enzymes, liver steatosis, balloon-like lesions of hepatocytes, inflammatory infiltrates in the liver lobules, and liver fibrosis. The results in fig. 2 demonstrate that at 32 weeks of induction, double knockout hyperlipidemic mice exhibited more severe hepatomegaly, elevated liver function enzymes, liver steatosis and hepatocyte balloon-like lesions, but no significant changes in inflammatory infiltrates and liver fibrosis within the liver lobules, relative to LDLR knockout hyperlipidemic mice.

Example 3

In this example, the liver weight, the liver body ratio, the liver functional enzyme level, the liver steatosis, the liver inflammatory response and the liver fibrosis of the above 4 animals were evaluated at 48 weeks of induction.

At 48 weeks of induction, animals were sacrificed under anesthesia after 12-16 hours of fasted, serum and tissue samples were collected, and liver tissue was weighed; detecting serum glutamic pyruvic transaminase and glutamic oxaloacetic transaminase levels by using a commercial kit; and HE staining and Masson staining were performed on paraffin sections of liver tissue to evaluate liver lesions.

The results are shown in FIG. 3, where A: liver weight; b: liver mass ratio; c: serum glutamic pyruvic transaminase level; d: serum glutamate oxaloacetic transaminase levels; e: HE staining; f: CD45 immunohistochemical staining; g: scoring hepatic steatosis; h: scoring liver balloon-like degeneration; i: scoring inflammation in the liver lobules; j: masson staining; k: scoring liver fibrosis; * P is less than 0.05, vs wild normal group; * P < 0.01, vs wild normal group; * P < 0.001, vs wild normal group; # and p < 0.01, vs wild high-fat group; # #, p < 0.001, vs wild high-fat group; the &, p is less than 0.01, vs LDLR knocks out the high-fat group; and & &, p < 0.001, vs LDLR knocks out the high fat group.

The liver paraffin section CD45 immunohistochemical staining mainly comprises the following steps: baking at 60 ℃ for 30 min, xylene (I) for 10 min, xylene (II) for 10 min, absolute ethanol (I) for 3 min, absolute ethanol (II) for 3 min, 95% ethanol (I) for 1 min, 70% ethanol for 1 min, distilled water for 2 min, 3% hydrogen peroxide for 10 min, PBS for three times (10 min/time), 95 ℃ rapid antigen retrieval solution for 10 min, PBS for three times (10 min/time), 5% BSA for 30 min at room temperature, primary antibody incubation at 4 ℃ for overnight, PBS for three times (10 min/time), secondary antibody for 60 min at room temperature, PBS for three times (10 min/time), DAB color development solution for room temperature incubation to moderate color development, PBS for three times (10 min/time), hematoxylin solution for 5-10 min, running water for 1-3 seconds, 1% hydrochloric acid for 1-2 seconds, running water for 20 min, and neutral resin sealing.

CD45 is a marker of inflammation. The results in fig. 3 show that at 48 weeks of induction, liver steatosis and hepatocyte balloon-like lesions in double-knockout hyperlipidemic mice were not significantly different compared to LDLR knockout hyperlipidemic mice, but still exhibited more severe hepatomegaly and elevated liver function enzymes, and significant and intense elevation of inflammatory infiltrates and liver fibrosis in the liver lobules.

Example 4

In this example, the number of liver tumors occurring in the 4 animals was counted and the tumors were identified 48 weeks after induction.

At 48 weeks of induction, 3 double-knock high-fat group mice are randomly selected, fasted for 8 hours, 1% pentobarbital sodium is injected into the abdominal cavity, 80mg/kg, after the mice are anesthetized, 5 μCi/g 18F-FDG is injected into tail vein, and PET/CT detection is carried out after 45 minutes, and liver neoplasia is observed; at 48 weeks of induction, animals were sacrificed under anesthesia 12 hours after fasted, serum and tissue samples were collected, the number of mice that died and developed liver tumors was counted for each group, and the liver tissue developed tumors was photographed generally; HE staining and AFP, PCNA, CD immunohistochemical staining of paraffin sections of liver tissue were performed to further define tumor lesions.

The results are shown in FIG. 4, where A: counting the number of tumor occurrence; b: PET/CT results of tumor mice; c: tumor tissue rough pictures; d: HE staining of tumor tissue; e: AFP staining of tumor tissue; f: PCNA immunohistochemistry of tumor tissues; g: tumor tissue CD31 immunohistochemistry.

Non-alcoholic steatohepatitis can partially develop into hepatocellular carcinoma, and has the characteristics of increased sugar intake at tumor sites, abnormal hyperplasia of tumor tissues, positive AFP, vascular hyperplasia and the like, PCNA and CD31 are respectively cell proliferation and vascular markers, and can be used for evaluating the conditions of cell proliferation and vascular hyperplasia. The results in fig. 4 show that, at 48 weeks of induction, the double-knockout high-fat mice show higher tumor incidence than the LDLR knockout high-fat mice, and the tumor tissues show significant tumor characteristics such as increased sugar uptake, abnormal proliferation, AFP positive and vascular proliferation.

Example 5

This example evaluates cardiovascular injury in the 4 animals described above at 48 weeks of induction.

At 48 weeks of induction, mice were examined for cardiac function using a Vevo 2100 small animal sonicator. The isoflurane inhalation anesthesia is carried out on the chest of the mouse, the chest of the mouse is dehaired by using dehairing paste under the anesthesia state, the mouse is placed on a constant temperature heating plate in a supine position, and the isoflurane is inhaled continuously. The four limbs of the mice are connected with electrocardiogram electrodes and are used for detecting heart rate and recording an electrocardiogram. 30MHz probe was used to probe the left sternum of mice. The aortic inner diameter at the outflow tract in diastole and systole was measured using M-ultrasound. Pulse Doppler is used to determine aortic valve outflow peaks and descending branch aortic blood peaks.

At 48 weeks of induction, animals were sacrificed under anesthesia after 12-16 hours of fasted, and aortic and cardiac tissue was collected. Carrying out integral oil red O staining on the aorta to evaluate the condition of the atherosclerosis plaque lesions; HE staining was performed on paraffin sections of heart tissue to assess myocardial hypertrophy.

The main steps of the aortic integral oil red O staining are as follows: the glass aorta was taken, rinsed in PBS until no blood stain, fixed overnight in 4% paraformaldehyde, and washed 3 times with PBS for 10 minutes each. And (3) shearing the aorta along the central axis, fixing the aorta on a black rubber plate, dyeing with oil red O working solution for 10-15 minutes, washing with PBS until no residual oil red O dye solution exists, photographing under a card type microscope, and counting the plaque area proportion by using Image J software.

Heart paraffin section HE staining, the main steps are: baking at 60 ℃ for 30 min, xylene (I) for 10 min, xylene (II) for 10 min, absolute ethanol (I) for 3 min, absolute ethanol (II) for 3 min, 95% ethanol (I) for 1 min, 70% ethanol for 1 min, distilled water for 2 min, hematoxylin solution for 5-10 min, running water for washing hematoxylin for 1-3 seconds, 1% hydrochloric acid alcohol for 1-2 seconds, running water for 20 min, distilled water for 1-2 seconds, 0.5% eosin for 2 min, distilled water for 1-2 seconds, 95% ethanol (II) for 2-3 seconds, absolute ethanol (III) for 3-5 seconds, absolute ethanol (IV) for 5-10 seconds, xylene (I) for 2 min, xylene (II) for 2 min, and neutral resin sealing sheet.

The results are shown in fig. 5, where a: an aortic inner diameter ultrasonic map; b: calculating the inner diameter of the aorta in diastole; c: counting the inner diameter of the aorta in the systolic period; d: aortic valve blood flow peak ultrasonic spectrum; e: aortic valve blood flow peak statistics; f: an ultrasonic spectrum of blood flow peaks of descending aorta; e: descending branch aortic blood flow peak statistics; f: aortic integral oil red O staining; g: counting the area proportion of aortic plaque; h: heart tissue HE staining; i: counting the area change of myocardial cells; * P is less than 0.05, vs wild normal group; * P < 0.01, vs wild normal group; * P < 0.001, vs wild normal group; # p < 0.05, vs wild high-fat group; # and p < 0.01, vs wild high-fat group; # #, p < 0.001, vs wild high-fat group; the &, p is less than 0.01, vs LDLR knocks out the high-fat group; and & &, p < 0.001, vs LDLR knocks out the high fat group.

Clinically 25% -40% of NASH patients are accompanied by cardiovascular disease, and cardiovascular disease has become a major factor in NASH patient death. The results in fig. 5 demonstrate that, at 48 weeks of induction, the double knockout hyperlipidemic mice exhibited more severe vascular lesions characterized by atherosclerosis relative to the LDLR knockout hyperlipidemic mice. More importantly, none of the wild normal, wild hyperlipidemic and LDLR knockout hyperlipidemic mice exhibited a cardiac hypertrophy phenotype, whereas the double knockout hyperlipidemic mice exhibited significant cardiac hypertrophy, suggesting the presence of myocardial injury.

The above embodiments are only illustrative of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention, and various modifications and improvements made by those skilled in the art to the technical solutions of the present invention should fall within the protection scope defined by the claims of the present invention without departing from the design spirit of the present invention.

Claims (6)

1. The construction method of the non-alcoholic steatohepatitis mouse model based on PEDF/LDLR double gene knockout is characterized by comprising the following construction steps:

(1) Mating the PEDF gene knockout mouse with the LDLR gene knockout mouse to obtain a PEDF/LDLR double-gene knockout mouse;

(2) Inducing high-fat feed to PEDF/LDLR double-gene knockout mice to obtain a non-alcoholic steatohepatitis mouse model;

in the step (1), the PEDF knockout mice and the LDLR knockout mice are C57BL/6J background;

the nutrient mass ratio composition of the high-fat feed in the step (2) comprises: 26.2% of protein, 26.3% of carbohydrate and 34.9% of fat.

2. The method for constructing a mouse model of nonalcoholic steatohepatitis according to claim 1, wherein the method is applied to the field of animal model construction.

3. The use of the mouse model constructed by the method for constructing a mouse model of nonalcoholic steatohepatitis according to claim 1 for screening or treating metabolic diseases.

4. The use according to claim 3, wherein the metabolic disease comprises obesity, hyperlipidemia, insulin resistance, diabetes, simple fatty liver, nonalcoholic steatohepatitis, nonalcoholic steatoliver-associated liver fibrosis, nonalcoholic steatoliver-associated liver cancer and nonalcoholic steatoliver associated cardiovascular injury.

5. The use according to claim 3, wherein the use comprises screening of drug targets, screening of drugs, pharmacodynamic evaluation of drugs and safety evaluation of drugs.

6. The use according to claim 4, wherein the use comprises screening of drug targets, screening of drugs, pharmacodynamic evaluation of drugs, and safety evaluation of drugs.

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