Construction method of a fatty pancreas mouse model and application thereof

Abstract

The application discloses a method for constructing a fatty pancreas mouse model and application thereof, and belongs to the field of animal model construction. The application discloses a method for constructing a fatty pancreas mouse model, which uses high-fat diet, streptozotocin and cerberus combined to induce mice to have pathological changes of pancreatic fat infiltration. The method for constructing the fatty pancreas mouse model is more targeted to directly model the fatty pancreas, and the obtained mouse model is more in line with the complex pathological characteristics in the fatty pancreas formation process, and can simultaneously simulate multiple pathological links such as metabolic abnormalities, pancreatic injury, inflammatory reaction and fat infiltration in the fatty pancreas formation process.

Description

Technical Field

[0001] This invention belongs to the field of animal model construction, specifically relating to a method for constructing a fatty pancreas mouse model and its application. Background Technology

[0002] Adipose pancreas refers to a pathological condition characterized by abnormal fat deposition or adipocyte infiltration within pancreatic tissue. In recent years, with the increasing incidence of obesity, type 2 diabetes, and metabolic syndrome, the relationship between adipose pancreas and diseases such as pancreatic islet dysfunction, pancreatitis, pancreatic fibrosis, and pancreatic tumors has gradually attracted attention. Establishing stable and reproducible animal models of adipose pancreas is crucial for studying its pathogenesis, evaluating interventions, and screening therapeutic targets.

[0003] In existing technologies, animal models related to fatty pancreas mainly fall into the following categories: The first category is diet-induced models, typically using C57BL / 6 mice. Mice are given a high-fat diet, a high-fat-high-sugar diet, or other metabolically stressful diets for a certain period, and then the mice are observed to exhibit obesity, insulin resistance, dyslipidemia, and pancreatic fat deposition. This method is relatively simple to operate and can simulate the pancreatic fat deposition process under metabolic abnormalities to a certain extent, making it a common experimental method. The second category is animal models of hereditary obesity or diabetes, such as ob / ob mice and db / db mice. These models can quickly induce obesity, hyperglycemia, or insulin resistance, accompanied by varying degrees of pancreatic lipid accumulation, suitable for observing changes in pancreatic structure and function under metabolic disorders. The third category is pancreatic injury or pancreatic duct obstruction-related models, such as pancreatic duct ligation and repeated induction of pancreatitis, which can lead to acinar cell damage, pancreatic atrophy, and fat replacement, often used to study the tissue remodeling process after pancreatic injury. Some studies also utilize animal models of metabolic-related fatty liver disease or steatohepatitis to incidentally observe pancreatic fat infiltration.

[0004] The aforementioned existing technologies have certain advantages. For example, diet-induced models more closely resemble the background of obesity and metabolic syndrome, are simple to operate, and have lower costs; hereditary obesity models have a relatively short modeling time and obvious metabolic phenotypes; pancreatic injury or pancreatic duct obstruction models can better reflect the fat replacement process after pancreatic parenchymal injury. These models provide a certain foundation for research on adipose pancreas.

[0005] However, existing technologies still have significant shortcomings. First, most existing models primarily focus on obesity, diabetes, fatty liver, or pancreatic injury, with fatty pancreas often only as a secondary observation indicator; there is a lack of specialized models specifically for fatty pancreas. Second, different studies use significantly different mouse strains, sexes, ages, dietary compositions, induction periods, and evaluation methods, leading to insufficient model reproducibility and comparability. Third, existing studies lack unified evaluation standards for pancreatic fat infiltration, fat distribution location, pathological scores, islet function, exocrine function, inflammatory responses, and fibrotic changes, making it difficult to objectively determine whether a model has been successfully established. Fourth, while some hereditary obesity or pancreatic injury models may show pancreatic fat deposition, their etiological mechanisms are not entirely consistent with those of common metabolic-related fatty pancreas in humans, potentially affecting the applicability of subsequent mechanistic studies and drug intervention evaluations.

[0006] Therefore, current technology still lacks a method for constructing a mouse model of fatty pancreas that has clearly defined modeling conditions, stable phenotypes, good reproducibility, and can comprehensively evaluate the model by combining pathological, metabolic, pancreatic endocrine and exocrine function, and molecular mechanism indicators. Establishing such a standardized model and evaluation system has significant application value for studying the pathogenesis of fatty pancreas, screening intervention measures, and developing related drugs and technologies. Summary of the Invention

[0007] The purpose of this invention is to provide a method for constructing an adipose pancreatic mouse model with clear modeling conditions, stable phenotype, good reproducibility, and the ability to comprehensively evaluate it by combining pathological, metabolic, pancreatic endocrine and exocrine function and molecular mechanism indicators.

[0008] In a first aspect, the present invention provides a method for constructing a fatty pancreas mouse model, which uses a high-fat diet, streptozotocin (STZ), and tazocin to induce pancreatic fatty infiltration in mice.

[0009] Preferably, it includes the following steps: S1: Adapted cultured mice; S2: Feed mice a high-fat diet for a certain period of time; S3: Mice were given staged injections of streptozotocin; S4: Mice were fed a high-fat diet to induce weight gain and their weight was then assessed. S5: Selected mice were induced by intraperitoneal injection of taurine to complete the construction of the fatty pancreas mouse model.

[0010] Preferably, the mouse is a male C57BL / 6 mouse.

[0011] Preferably, in step S2, the specific steps are: feeding the animal with a high-fat diet for 6 weeks, wherein the lipid energy percentage of the high-fat diet is 50% to 70%.

[0012] Preferably, in S3, streptozotocin is injected continuously for three days, once a day, with a dose of 60-80 mg / kg mouse body weight each time.

[0013] Preferably, streptozotocin is dissolved in 0.1 mol / L sodium citrate buffer solution with pH 4.2-4.5 and is prepared fresh for use.

[0014] Preferably, in step S3, mice are fasted for 20-24 hours before the first injection of streptozotocin in the staged injection, and are given a high-fat diet and brown sugar water during the streptozotocin stage; brown sugar water is stopped after the third injection of streptozotocin in the staged injection.

[0015] Preferably, setting operational conditions such as fasting before induction, fresh preparation and use, short-term drinking of brown sugar water, and discontinuation of brown sugar water after the third STZ injection during streptozotocin induction can reduce the risk of acute hypoglycemia and stress response while ensuring modeling effect, and improve animal survival rate and subsequent experimental success rate.

[0016] Preferably, in step S4, mice are fed a high-fat diet for 0 to 4 weeks; the screening involves excluding mice weighing more than 38g.

[0017] Preferably, in step S5, the intraperitoneal injection of taurine is continued for 4 weeks, with 3 injection days selected each week, 3 injections on each injection day, with an interval of 1 hour between each injection, and the dose is 80~120μg / kg mouse body weight each time. During the injection period, the mouse is fed a high-fat diet.

[0018] Preferably, step S5 further includes feeding mice with a high-fat diet for 0-16 weeks after completing the induction of taurine, to obtain a fatty pancreas mouse model with further aggravated fatty infiltration.

[0019] Secondly, the present invention provides applications of the above-mentioned method for constructing a fatty pancreas mouse model, including at least one of the following: research on the mechanism of fatty pancreas formation, screening of molecular targets related to pancreatic fat infiltration, research on anti-inflammatory, anti-fibrotic or glucose and lipid metabolism-improving drugs, and research on signaling pathways related to adipogenesis, inflammatory response, oxidative stress, lipotoxic damage and fibrosis during fatty pancreas formation.

[0020] Preferably, the present invention can combine hematoxylin-eosin staining, oil red O staining, Masson's trichrome staining, immunohistochemistry or immunofluorescence, metabolic indicators and pancreatic endocrine function detection to comprehensively determine the fatty pancreas model.

[0021] Compared with the prior art, the present invention has the following advantages: The method for constructing a fatty pancreas mouse model provided by this invention is more targeted, with the fatty pancreas as the direct modeling objective. By combining a high-fat diet, STZ staged intervention, and repeated stimulation with taurine, it can more specifically induce pancreatic fatty infiltration and related pathological changes.

[0022] The method for constructing a fatty pancreas mouse model provided by this invention produces a mouse model that more closely resembles the complex pathological characteristics of fatty pancreas development. It is not a single-factor induced model, but rather a model that, based on a background of metabolic abnormalities caused by a high-fat diet, combines STZ-induced glucose and lipid metabolism disorders and pancreatic endocrine damage, and further induces pancreatic damage and tissue remodeling through repeated stimulation with taurine. This combined approach can simultaneously simulate multiple pathological processes during fatty pancreas formation, including metabolic abnormalities, pancreatic damage, inflammatory responses, and fatty infiltration.

[0023] The method for constructing a fatty pancreas mouse model provided by this invention results in a mouse model with stable phenotype, thereby improving the stability and reproducibility of the fatty pancreas mouse model construction. Attached Figure Description

[0024] Figure 1 Gross view of the pancreas in the combined group in Example 2; Figure 2 Gross view of the pancreas in the XTHF60 high-fat diet group in Example 2; Figure 3 Gross pancreatic image of the group receiving the XTHF60 high-fat diet combined with three injections of taurine in Example 2; Figure 4 Figure 2 shows the body weight of mice in each group in Example 2; Figure 5 This is a graph showing the pancreas weight of mice in each group in Example 2; Figure 6 The image shows the pancreatic index of each group of mice in Example 2; Figure 7 HE staining image of pancreatic sections from mice in the normal diet control group in Example 2; Figure 8 HE staining image of pancreatic sections from mice in the XTHF60 group in Example 2; Figure 9 HE staining image of pancreatic sections from mice in the XTHF60+CAE3 group in Example 2; Figure 10 HE staining image of pancreatic sections from mice in the XTHF60+CAE6 group in Example 2; Figure 11 HE staining image of pancreatic sections from mice in the combined group in Example 2; Figure 12 HE staining image of pancreatic sections from mice in the 8-week combined group in Example 2; Figure 13HE staining image of pancreatic sections from mice in the 12-week combined group in Example 2; Figure 14 This is an image of Oil Red O staining detection of mice in the combined group in Example 2; Figure 15 The graph shows the fasting blood glucose levels of mice in each group in Example 2. Figure 16 The graphs show the triglyceride levels in each group of mice in Example 2. Figure 17 The graph shows the total cholesterol levels in each group of mice in Example 2. Figure 18 The graph shows the glycated hemoglobin levels in each group of mice in Example 2. Figure 19 The glucose tolerance test blood glucose-time curves for the combined group mice and normal control mice in Example 2 are shown. Figure 20 This is a graph showing the area under the glucose tolerance curves of the combined group mice and normal control mice in Example 2. Figure 21 HE staining image of pancreatic sections from mice in the experimental group in Example 3; Figure 22 HE staining image of pancreatic sections from mice in the experimental group in Example 3; Figure 23 The glucose tolerance test blood glucose-time curves for the experimental group mice and normal control mice in Example 3 are shown. Figure 24 This is an area under the glucose tolerance curve for experimental mice and normal control mice in Example 3. Detailed Implementation

[0025] To better understand the present invention, the following embodiments are further illustrations of the invention, but the scope of the invention is not limited to these embodiments. Unless otherwise specified, the experimental methods used in the embodiments of the present invention are conventional methods. The reagents and materials used in the embodiments are all commercially available, and the quantitative experiments involved in the embodiments are all performed in at least three replicates.

[0026] The present invention adopts the following technical solution: S1. Preparation of laboratory animals Six-week-old male C57BL / 6 mice were selected and placed in an SPF-grade barrier environment for one week for acclimatization. During the acclimatization period, the mice were given normal food and water to allow them to adapt to the experimental environment and reduce the impact of environmental stress on subsequent modeling results.

[0027] S2. High-fat diet pre-induction After the acclimatization period, mice were fed a high-fat diet for 6 weeks. This was used to induce obesity, abnormal lipid metabolism, and alterations in the pancreatic lipid metabolism microenvironment in mice, providing a metabolic basis for subsequent adipose pancreas formation.

[0028] The high-fat feed is not limited and can be any fat-based energy high-fat feed, including XTHF60 high-fat feed (Shulaibao), XTCD60 feed (Jiangsu Xietong Biotechnology), etc.

[0029] S3.STZ staged intraperitoneal injection The patient received streptozotocin (STZ) injections for three consecutive days, and was fed a high-fat diet and given brown sugar water during the injection period. This treatment aims to further establish a state of glucose and lipid metabolism disorder based on the metabolic abnormalities induced by a high-fat diet, promoting pancreatic endocrine dysfunction and the formation of pathological changes related to adipose pancreas.

[0030] The brown sugar water is used to reduce the risk of acute hypoglycemia and stress response after STZ injection.

[0031] S4. Continue high-fat diet induction. After completing the third STZ injection and discontinuing the use of brown sugar water, mice were continued to be fed regular drinking water and a high-fat diet for 0–4 weeks. This was used to maintain and enhance the disordered glucose and lipid metabolism in mice, placing the pancreas in a continuous metabolic stress environment, thus providing the basis for subsequent pancreatic damage and fatty infiltration induced by taurine.

[0032] After 0-4 weeks of high-fat diet induction, mice were screened by weight, and overweight mice were removed to reduce the impact of excessively obese individuals on the stability and consistency of the model, and to improve the uniformity and reproducibility of the fat pancreas model.

[0033] S5. Repeated intraperitoneal injection of hygroscin to induce induction The patient was repeatedly and continuously intervened with thymol for 4 weeks, and continued to be fed a high-fat diet during the intervention period. This was used to further cause repeated pancreatic stimulation and pancreatic tissue damage on the basis of metabolic abnormalities induced by high-fat diet and STZ, promote changes related to pancreatic fat infiltration, and thus stabilize the pathological phenotype of fatty pancreas.

[0034] After four weeks of continuous intervention with spirulina, the adipose pancreas mouse model was successfully established. To further enhance pancreatic fat infiltration, a high-fat diet can be continued for 0–16 weeks after spirulina intervention, and the sampling period can be extended.

[0035] S6. Determination of the fatty pancreas model Pancreatic tissue and blood samples were collected from mice for model evaluation. Hematoxylin and eosin (HE) staining, Oil Red O staining, Masson's trichrome staining, immunohistochemistry, or immunofluorescence were used to observe and evaluate the degree of pancreatic fat infiltration, fat distribution characteristics, acinar damage, inflammatory cell infiltration, degree of fibrosis, and changes in islet structure. Simultaneously, the metabolic phenotype and pancreatic exocrine and endocrine functions of the model mice were comprehensively evaluated by combining body weight, blood glucose, blood lipids, insulin levels, glucose tolerance test, insulin tolerance test, and pancreatic exocrine indicators.

[0036] The fat pancreas mouse model can be considered successfully established when mice show clear pancreatic fat infiltration, accompanied by pancreatic tissue damage, metabolic abnormalities, and changes in pancreatic function.

[0037] The effects of the present invention will be described in detail below with reference to the embodiments.

[0038] The mice used in this invention were all C57BL / 6 mice, sourced from Jicui Pharmaceutical Co., Ltd., 6 weeks old, male, weighing between 22 and 26 g. The mice were housed in an SPF-grade barrier environment (GB 14925-2023).

[0039] All animal experiments in this invention were conducted in accordance with the charter of the Experimental Animal Ethics Committee of Wuhan University.

[0040] All data in this invention were analyzed using GraphPad Prism 10.0. First, normality and homogeneity of variance were tested. Quantitative data conforming to normal distribution and homogeneity of variance were expressed as mean ± standard deviation (Mean ± SD). Independent samples t-tests were used to compare data between two groups. One-way ANOVA was used to compare data among multiple groups, with LSD tests for pairwise comparisons. A p-value < 0.05 was considered statistically significant, and statistical significance was indicated as: no statistically significant difference in ns. P<0.05; P<0.01; P<0.001, P<0.0001.

[0041] Example 1: Method for constructing a fatty pancreas mouse model 1. High-fat diet pre-induction Six-week-old male C57BL / 6 mice were placed in an SPF-grade barrier environment for one week of acclimatization, during which they were given normal feed and water. After the acclimatization period, the mice were switched to a high-fat diet using 60% fat functional high-fat feed from Shulaibao (product code XTHF60, abbreviated as XHF60 in the attached image), and fed continuously for 6 weeks.

[0042] 2. STZ staged intraperitoneal injection After 6 weeks of high-fat diet feeding, mice were administered streptozotocin (STZ, MCE, HY-13753) via intraperitoneal injection. Mice were fasted for 20-24 hours prior to the first STZ injection, but were allowed free access to water. The STZ dosage was calculated at 60 mg / kg mouse body weight. The STZ injection solution was rapidly dissolved in 0.1 mol / L, pH 4.5 sodium citrate buffer and prepared fresh before use. Immediately after the first STZ intraperitoneal injection, the high-fat diet was resumed, and mice were given brown sugar water (prepared by dissolving 10g of brown sugar in 100ml of drinking water).

[0043] On the second and third days after the initial STZ injection, mice were given another intraperitoneal injection of STZ at the same time points, each time at a dose of 60 mg / kg body weight, for a total of 3 consecutive days. After the third STZ injection, the mice were no longer given brown sugar water, but instead given regular water and continued to be fed a high-fat diet.

[0044] 3. Continue high-fat diet induction and screening. After 4 weeks of feeding with a high-fat diet, mice were screened by weight, and mice weighing >38 g were removed.

[0045] 4. Induction by repeated intraperitoneal injection of basilin After weight screening, the remaining mice were administered spirulina extract (Shanghai Yuanye Company, S62702) via intraperitoneal injection. The dosage of spirulina extract was calculated at 100 μg / kg mouse body weight. The injection frequency was three days a week, preferably Tuesday, Thursday, and Saturday; three injections were given each day, with one hour intervals between each injection, for a total of three consecutive hours. The spirulina extract intervention was continued for four weeks, during which time the mice were fed a high-fat diet.

[0046] After four weeks of continuous intervention with taurine, the adipose pancreas mouse model was successfully established. To further enhance pancreatic fat infiltration, a high-fat diet was continued after taurine intervention, and the sampling period was extended to 8 and 12 weeks.

[0047] Example 2: Evaluation of the effect of the fatty pancreas mouse model The adipose pancreas mouse model was constructed using the method described in Example 1. After intervention with thymol, the mice were fed a high-fat diet for 8 and 12 weeks, respectively, resulting in the combined group (IR+CAE3), the 8-week combined group, and the 12-week combined group.

[0048] The study included a control group with a normal diet, a high-fat diet group with XTCD60 (XTCD60), a high-fat diet group with XTHF60 (XTHF60), a high-fat diet group with XTCD60 plus 3 injections of oxaliplatin (XTCD60+CAE3), a high-fat diet group with XTCD60 plus 6 injections of oxaliplatin (XTCD60+CAE6), a high-fat diet group with XTHF60 plus 3 injections of oxaliplatin (XTHF60+CAE3), and a high-fat diet group with XTHF60 plus 6 injections of oxaliplatin (XTHF60+CAE6).

[0049] Specifically, the normal diet control group, the XTCD60 high-fat diet group, and the XTHF60 high-fat diet group were given only normal drinking water and normal feed, XTCD60 high-fat feed, or XTHF60 high-fat feed, respectively.

[0050] The XTCD60 high-fat diet combined with three injections of crotonin and the XTHF60 high-fat diet combined with three injections of crotonin were cultured on XTCD60 high-fat diet or XTHF60 high-fat diet, respectively, and crotonin was injected intraperitoneally after 10 weeks of high-fat diet; the method of intraperitoneal injection of crotonin was the same as that in Example 1.

[0051] The XTCD60 high-fat diet combined with 6 injections of crotonin and the XTHF60 high-fat diet combined with 6 injections of crotonin were cultured on XTCD60 high-fat diet or XTHF60 high-fat diet, respectively. After 10 weeks of high-fat diet, crotonin was injected intraperitoneally. The method of intraperitoneal injection of crotonin was different from that in Example 1 only in that 6 injections were given on each injection day, with an interval of 1 hour between each injection.

[0052] 1. General condition assessment of mice The mice in each group were weighed, and after sacrifice, their pancreas was harvested for gross observation and weighing. The pancreatic index was then calculated. The formula for calculating the pancreatic index is as follows: Pancreas index % = (pancreas weight / mouse body weight) 100% Gross view of the pancreas in the combined group as follows Figure 1 As shown, the gross pancreas of the XTHF60 high-fat diet group is as follows. Figure 2 As shown, the gross appearance of the pancreas in the XTHF60+CAE3 group is as follows. Figure 3 As shown, it can be seen that the pancreatic surface of the combined group has obvious fatty infiltration, while the pancreatic surface of the other two groups does not have obvious fatty infiltration.

[0053] The body weight of mice in each group is as follows: Figure 4 As shown, it can be seen that except for the XTCD60 high-fat diet group and the XTHF60 high-fat diet group, the weight of mice in the other groups did not change significantly, indicating that the excessively obese individuals in the combined group had a low impact on the stability and consistency of the model.

[0054] Pancreas weight in each group of mice is as follows: Figure 5 As shown, the pancreatic weight of the XTHF60 high-fat diet group increased significantly, while the pancreatic weight of the XTCD60+CAE6 group decreased significantly, and the combined group showed an even more significant decrease in pancreatic weight; the pancreatic index of each group is as follows: Figure 6 As shown, the pancreas in the combined group was significantly lower than that in the other groups, indicating that the pancreas of the mice in the combined group was significantly atrophied and damaged.

[0055] 2. Histopathological evaluation 2.1 HE staining Pancreatic sections were collected from mice in the normal diet control group, XTHF60 group, XTHF60+CAE3 group, XTHF60+CAE6 group, combined group, 8-week combined group, and 12-week combined group. HE (hematoxylin-eosin, G1003, Wuhan Saiwell Biotechnology Co., Ltd., Wuhan, China) staining was performed to observe cell and tissue morphology.

[0056] HE staining of pancreatic sections from mice in the normal diet control group, XTHF60 group, XTHF60+CAE3 group, XTHF60+CAE6 group, combined group, 8-week combined group, and 12-week combined group is as follows: Figures 7-13As shown, the XTHF60 group fed a high-fat diet alone showed no significant difference from normal mice; the overall structure of the pancreatic tissue remained largely intact, the acini were arranged relatively regularly, and no obvious abnormalities were observed in the interstitium. The XTHF60+CAE3 and XTHF60+CAE6 groups both showed varying degrees of pancreatic tissue damage, without fat infiltration, but exhibited disordered acinar structure, widened interstitium, and inflammatory cell infiltration, accompanied by local acinar atrophy. Further observation revealed fibrous connective tissue hyperplasia in some areas of the pancreatic interstitium in both groups, with more pronounced tissue structure destruction and interstitial fibrosis in the XTHF60+CAE6 group. The combined group, the 8-week combined group, and the 12-week combined group showed significant acinar cell loss and adipocyte infiltration; significant adipose tissue infiltration was observed, with adipocytes mainly distributed between acini and in the interlobular spaces of the pancreas. In some areas, the extent of fat infiltration expanded, accompanied by local acinar structural compression, disordered arrangement, and widened interstitium. This indicates that, unlike the high-fat diet induction and combined taurine induction, the combined group constructed a fatty pancreas mouse model with clear pancreatic fatty infiltration and no obvious inflammatory response or fibrotic changes.

[0057] 2.2 Oil Red O staining detection Frozen sections of the pancreas from mice in the combined group were taken and stained with Oil Red O (G1015, Wuhan Saiwell Biotechnology Co., Ltd., Wuhan, China) to observe the location, number, and size of lipid droplets.

[0058] Oil Red O staining detection in the combined group of mice is as follows: Figure 14 As shown, red lipid droplets are distributed in the mouse pancreas, indicating the presence of pancreatic lipid deposition, consistent with the characteristics of an adipose pancreas.

[0059] 3. Evaluation of metabolic indicators in mice In addition, peripheral blood samples were collected from mice in each group, and fasting blood glucose, triglycerides, total cholesterol, and glycated hemoglobin levels were measured using a fully automated biochemical testing instrument at the Department of Laboratory Medicine, Renmin Hospital of Wuhan University.

[0060] The levels of fasting glucose, triglycerides, total cholesterol, and glycated hemoglobin (HbA1c) in each group of mice are as follows: Figures 15-18As shown, the results of blood lipid level testing indicate that serum triglyceride (TG) levels were significantly higher in the combined group, XTHF60 diet group, XTHF60+CAE3 group, and XTHF60+CAE6 group than in the normal control group, while there were no statistically significant differences between the XTCD60 group, XTCD60+CAE3 group, and XTCD60+CAE6 group and the normal control group. Further testing of serum total cholesterol (TC) levels revealed that TC levels in the combined group, XTHF60 diet group, XTHF60+CAE3 group, XTHF60+CAE6 group, XTCD60 group, XTCD60+CAE3 group, and XTCD60+CAE6 group were significantly higher than in the normal control group. Blood glucose level testing showed that fasting blood glucose levels were significantly higher in the combined group than in the other groups, indicating severe impairment of basal insulin secretion function and significant damage to pancreatic endocrine function in the combined group mice. Glycated hemoglobin levels were also significantly higher in the combined group than in the other groups, indicating that the combined group mice had abnormal long-term glycemic control and impaired pancreatic function, consistent with the characteristics of fatty pancreatic mice.

[0061] 4. Intraperitoneal Glucose Tolerance Test (IPGTT) in mice Glucose tolerance tests were conducted on mice in the normal diet control group and the combined group (marked as FP, or fatty pancreas, in the figure).

[0062] Mice were fasted for 14 hours before the experiment, but had free access to water. After fasting, the mice were weighed, and fasting blood glucose levels were measured using the tail tip blood sampling method, recorded as the 0-minute blood glucose value. Subsequently, 20% glucose solution was injected intraperitoneally at a dose of 2 g / kg body weight, and tail tip blood glucose levels were measured at 15, 30, 60, 90, and 120 minutes after the glucose load. Blood glucose values ​​at each time point were recorded, blood glucose curves were plotted, and the area under the curve (AUC) was calculated to evaluate the glucose tolerance of different groups of mice.

[0063] The glucose-time curves and area under the glucose curve for glucose tolerance tests in mice are shown below. Figure 19 , 20 As shown, the combined group mice had significantly higher blood glucose levels than the normal diet control group at all time points after glucose loading; the combined group mice had significantly increased AUC, indicating that the mice had impaired glucose tolerance and insufficient insulin secretion capacity.

[0064] Based on the above experimental results, it can be concluded that the combined group mice obtained using the method in Example 1 showed clear pancreatic fatty infiltration, accompanied by pancreatic tissue structural damage, abnormal glucose and lipid metabolism, and changes in pancreatic exocrine and endocrine functions. Moreover, compared with mice induced by a high-fat diet alone or by a high-fat diet combined with hygroscopic hormones, the combined group mice had milder inflammatory responses and less fibrotic changes, which is more consistent with the characteristic definition of fatty pancreas.

[0065] Example 3: Accelerated Construction Method of Fatty Pancreas Mouse Model The only difference between this embodiment and embodiment 1 is that in step 3, the mice were fed a high-fat diet for 0 weeks, that is, after completing STZ induction, the mice were directly screened for weight and induced with taurine.

[0066] The experimental group (FP group) was obtained using the above methods, and a control group (CON group) with a normal diet was set up.

[0067] 1. HE staining Pancreatic sections were taken from the control group and the experimental group and subjected to HE (hematoxylin-eosin, G1003, Wuhan Saiwell Biotechnology Co., Ltd., Wuhan, China) staining to observe cell and tissue morphology.

[0068] The HE staining results of the control group with a normal diet were the same as those in Example 2. The staining results of the experimental group were as follows: Figure 21 , 22 As shown, the pancreatic slices of the experimental group showed obvious loss of acinar cells, filling and infiltrating with fat cells, and obvious adipose tissue infiltration. Furthermore, the inflammatory response and fibrotic changes were not obvious.

[0069] 2. Intraperitoneal Glucose Tolerance Test (IPGTT) in mice Mice in the control and experimental groups were subjected to glucose tolerance tests using the method described in Example 2.

[0070] The glucose-time curves and area under the glucose curve for glucose tolerance tests in mice are shown below. Figure 23 , 24 As shown, the blood glucose levels of the experimental group mice were significantly higher than those of the control group at all time points after glucose loading; the AUC of the experimental group mice was significantly increased, indicating that the mice had impaired glucose tolerance and insufficient insulin secretion capacity.

[0071] Based on the above experimental results, it can be concluded that the experimental group mice obtained using the method in this embodiment showed clear pancreatic fatty infiltration, accompanied by abnormal glucose and lipid metabolism, and no obvious inflammatory response or fibrotic changes, proving the successful modeling of fatty pancreas mice. This indicates that reducing the high-fat diet induction time between streptozotocin induction and viviparin induction in mice can significantly reduce the modeling time of fatty pancreas mice without affecting the modeling effect.

[0072] The above description is merely a preferred embodiment of the present invention, and should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for constructing a fatty pancreas mouse model, characterized in that, Mice were induced to develop pancreatic fatty infiltration by a combination of a high-fat diet, streptozotocin, and hygroscopic lecithin.

2. The method for constructing a fatty pancreas mouse model according to claim 1, characterized in that, Includes the following steps: S1: Adapted cultured mice; S2: Feed mice a high-fat diet for a certain period of time; S3: Mice were given staged injections of streptozotocin; S4: Mice were fed a high-fat diet to induce weight gain and their weight was then assessed. S5: Selected mice were induced by intraperitoneal injection of taurine to complete the construction of the fatty pancreas mouse model.

3. The method for constructing a fatty pancreas mouse model according to claim 2, characterized in that, The mice were male C57BL / 6 mice.

4. The method for constructing a fatty pancreas mouse model according to claim 2, characterized in that, In step S2, the specific steps are as follows: feeding the animal with a high-fat diet for 6 weeks, wherein the lipid energy percentage of the high-fat diet is 50% to 70%.

5. The method for constructing a fatty pancreas mouse model according to claim 2, characterized in that, In S3, streptozotocin was injected continuously for three days, once a day, with a dose of 60-80 mg / kg mouse body weight each time.

6. The method for constructing a fatty pancreas mouse model according to claim 2, characterized in that, In S3, mice are fasted for 20-24 hours before the first injection of streptozotocin in the staged injection, and are given a high-fat diet and brown sugar water during the streptozotocin stage; brown sugar water is stopped after the third injection of streptozotocin in the staged injection.

7. The method for constructing a fatty pancreas mouse model according to claim 2, characterized in that, In step S4, mice are fed a high-fat diet for 0-4 weeks; the screening process involves excluding mice weighing more than 38g.

8. The method for constructing a fatty pancreas mouse model according to claim 2, characterized in that, In S5, the intraperitoneal injection of taurine was administered for 4 weeks, with 3 injection days selected each week. Each injection day was administered 3 times, with an interval of 1 hour between each injection. The dose was 80~120μg / kg of mouse body weight each time, and the mice were fed a high-fat diet during the injection period.

9. The method for constructing a fatty pancreas mouse model according to claim 2, characterized in that, S5 further includes feeding mice with a high-fat diet for 0-16 weeks after completing the induction of taurine, to obtain a fatty pancreas mouse model with further aggravated fat infiltration.

10. The application of a method for constructing a fatty pancreas mouse model as described in any one of claims 1 to 9, characterized in that, This includes at least one of the following: research on the mechanism of adipose pancreas formation, screening of molecular targets related to pancreatic fat infiltration, research on anti-inflammatory, anti-fibrotic or glucose and lipid metabolism-improving drugs, and research on signaling pathways related to adipogenesis, inflammatory response, oxidative stress, lipotoxic damage and fibrosis during the formation of adipose pancreas.

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