| Objective:To establish ananimal model of fatty liver disease, which occurrence and development process is similar to human, and therebyto explore the damage mode of high fat diet joint drinking on the liver and the relationship between fatty liver disease and insulin resistance, in order to provide experimental information for clinical studies.Methods: 120 C57BL/6J mice were divided into two groups randomly, half male and half female. Control animals drank water freely, giving basal feed; Model animals drank 20% ethanol solution freely, feeding with high-fat diet(homemade). Chose 10 mice from each group randomly after feeding 1 week, 2 weeks, 4 weeks and 7 weeks, respectively, half male and half female, observing the morphological change of liver dynamically until the livers showed morphologicalevidences of fatty liver disease. After 7 weeks,let the remaining mice fast for 12 hours, weighing and taking blood from the orbital venous plexus. Detectedfasting insulin, serum ALT, AST, TBA, TG, CHO, TBIL, ALP, GLUand FFA. The mice were then sacrificed and the expression of TG, T-SOD, MDA, ADH, ALDH and T-AOC in their livers was measured. Moreover, routine morphological changes(HE stain and oil red O stain) and ultrastructural changes of livers were detected.Results:1There waseach 1 mouse accidental deathduring 6th and 7th week.2 HE staining results of liver tissue sections showed that, the fatty degeneration of hepatocyte increased gradually in model animals from 2 weeks after modeling. It appeared diffuse macrovesicular fatty degeneration of hepatic cells in model animals at 7th week, presenting evidences of fatty liver disease. The hepatocytes of model group animals also showed a few of liver cells necrosis. There is no obviously hepatocyte fatty degeneration in control group.2 The liver tissue sections stained by oil red O showed the red lipid dropletsincreased graduallyin livers of model animals. There were a large number of different sizes of red lipid droplets dispersed in the model animals after 7 weeks. The lipid droplets in control animals were significantly less than model group.3 Compared with the control group, body weight of male animals in model group increased by 4.20%(P<0.05) after 7 weeks, liver weight increased by 6.36%(P<0.05); female animal body weight increased by 8.29%(P < 0.01), liver weight increased by 10.23%(P < 0.01). There is no significant increase in hepatosomatic index in both male and female animals(no significant difference).4 Compared with the control group, serum ALT levels in model group doubled after 7 weeks, serum AST level increased by 81%, serum TBA level increased by 108%, serum TG level increased by 27% and serum CHO level increased by 57%(all P< 0.01); the level of serum TBIL, ALP, GLU and FFA were no significant change.5 Compared with the control group, the liver TG level increased by 27%(P< 0.05), the MDA level increased by 53%(P< 0.01), T-AOC decreased by 35%(P< 0.01); the level of ADH, ALDH and T-SOD were no statistical differencein model group after 7 weeks.6 Compared with control group, the level of group of fasting blood glucose went up slightly(no statistical difference), the fasting insulin level and the HOMA-IR increased significantly(P< 0.01) in model animals after 7 weeks.7 The ultrastructural of animals’ liver in model group showed that the hepatic cells had loosened cytoplasm, irregular margin and indistinct nucleus. The electron density of nucleus was decreased. The mitochondria were swelling and their cristae were vague. The rough endoplasmic reticulum were dilated and fractured. There were visible fat droplets of different size deposition in the cytoplasm.Conclusions:1 After establishing a fatty liver disease model by alcoholic and high-fat diet in C57BL/6J mice for 7 weeks, the body weight and liver weight of model animals were obviously higher than control animals; animal liver morphological evidence showed the clinical manifestations of fatty liver disease.2 After establishing a fatty liver disease model by alcoholic and high-fat diet in C57BL/6J mice for 7 weeks, serum ALT, AST, TBA, TG and CHO levels were significantly elevated and hepatic TG level was also significantly increased in model group animals. The change tendencies of each detected data in livers were very similar to that of human, which demonstrated the establishing of model is successful.3 After establishing a fatty liver disease model by alcoholic and high-fat diet in C57BL/6J mice for 7 weeks, liver MDA was significantly increased while liver T-AOC was significantly decreased, which demonstrated oxidative stress and lipid peroxidation may be involved in the pathogeny of fatty liver disease in our study.4 After establishing a fatty liver disease model by alcoholic and high-fat diet in C57BL/6J mice for 7 weeks, the fasting blood glucose level increased slightly; the fasting insulin level increased two times. The insulin resistance index(HOMA-IR) in model group animals was significantly higher than in control group animals. It shows that the insulin resistance(IR) occurred in the progress of model building. |
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