| Objective:The rate of nonalcoholic fatty liver disease (NAFLD) is rising year by year .This disease often co-exist with fat,diabetes2,hyperlipemia .In recent years,it is found that nonalcoholic fatty liver disease is closely connected with insulin resistance and diabetes, insulin resistance and 2 diabetes might function as the starting factor forming of nonalcoholic fatty liver disease and play a central role in the forming of nonalcoholic fatty liver disease. Peroxisome proliferator activated receptorα(PPARα) is a transcriptor activated by ligand which belongs to the super family of nuclear receptor,and performs the role of adjusting the metabolism of fat,inflammation,immunity and cell differenttiation.It plays an important role in nonalcoholic fatty liver disease. Hepatocyte nuclear factor-4α, (HNF4α)is one of the members of the highly conservative super-family of cholesteremia /thyroid h's receptor and it is expressed in liver, kidney, bowels and insulin cell. HNF4αalso plays an important role in nonalcoholic fatty liver disease. As what is shown in the research, that the mice model of insulin resistance and type 2 diabetic fed by high fat, the HNF4αmRNA in liver will down. This research shows that 2 diabetes induced by long-term high-fat feeding accompanied with intraperitonealinjection of streptozotocin (STZ), identifies the interaction of HNF4αmRNA and Peroxisome proliferator activated receptorαmRNA with nonalcoholic fatty liver disease and illustrates the patho genetic system, thus to find some new methods to present nonalcoholic fatty liver disease effectively.Method: Forty-five healthy and male Wistar mice are chosen as the sample. After being fed flexing for two weeks, they are divided random into commom feeding group (15mice) which functions as normal comparative team, and high fat feeding group (30mice) which functions as the experimental team. The experimental team is fed with high fat food for eight weeks.Then blood was taken from them to assess their blood sugar, level of insulin. The index of insulin resistance increases and the mice model of insulin resistance is successful. Then ,the experiment team is divided into two groups,(group B and group C). Group B is fed with high fat food. Group C is also fed with high fat food and at the same time provide them with rosiglitazone (RSG ). This process continues for eight weeks. All the mice are allowed to drink and eat freely. Every five mice are raised in one cage. Every mouse is weighed and their blood is taken at the beginning and end of the experiment respectively. The mice are prohibited from eating at 20 o'clock one day previous to the experiment.At 8 o'clock in the experiment day, three milliter blood is taken from medial canthus of eyes.The blood serum is separated. Then it is kept in the temperature of -20℃and used for test of various index. The experiment fininshed, part of the liver is kept in the liquid nitrogen to test the expression of PPARαand HNF4, part of the structure are fixed for histological analysis.1 Assays blood glucose and insulinWe measured fasting glucose by glucose oxidase method, and insulin by radioimmunoassay on serum samples. The level of insulin resistance was evaluated according to Homeoestasis Model Assessment (HOMA-IR) and Insulin Sensitivity Index (ISI).2 Assays of blood fatTriglyceride(TG), total cholesterol(TC) were measured by chromometry. FFA was measured by Cu2+chromatometry.3 Expression of PPARαand HNF4αmRNA of liver tissueThe rat liver tissues mRNA was extracted with Trizol Kit. The PPARα,HNF4αand their respectivelyβ-actin were amplified respectively by RT-PCR. The RT-PCR products were observed by agarose gel electrophoresis, photo was taken and the density of PPARα,HNF4αandβ-actin band were scanned. The relative expression quantity of specific band was represent- ed with the ratio of band densitometry unit of PPARαand HNF4αto the respectivelyβ-actin.4 The morphological eximination of liver tissueThe tissue section was made by routine method for light microscopy examination.5 Statistical methods All data were treated with SPSS13.0, and all continuous variable were presented as mean±SD. The statistic significance of between means was determined by T-test. One-way ANOVA was used to compare continuous variables among groops. The significance was indicated by P. The differe-nce which had the significance was indicated by P<0.05,and the difference which had the largest significance was inditicated by P<0.01.Results1 Body weight: There was no statistically significant difference in weight among each group of the rats at the beginning of the experiment. At the end of the experiment, the weight of rats in group B and group C was significantly higher than that in group A (P<0.05), and there was no significant difference between group C and group B (P>0.05).2 Blood glucose and insulin: There was no significant difference in fasting glucose among the rats of each group at the beginning of the experiment. After the injection of STZ, the blood glucose level of model rats and the rats treated with rosiglitazone significantly raised up from normal baseline (P<0.01). The blood glucose level of rats treated with rosiglitazone was lower than that of model rats (P<0.01), but it was still hyperglycemia. The insulin level of model rats was markedly higher than that of rats treated with rosiglitazone and normal control rats (P<0.01), The insulin level of normal control rats lower than that of rats treated with rosiglitazone (P<0.05).3 Blood lipid: The plasma levels of TG, TC and FFA in rats with T2DM were obviously higher than those in normal control rats (P<0.01). After treated with rosiglitazone, their plasma levels decreased to some extent, but they were still higher than those in normal control rats.4 The pathologic change of liver: the liver color of the normal comparison group is red and brown, soft. The liver color of the high fat feeding group and rosiglitazone interference group's is light yellow or khaki , it is oily. Drops of oil come into being when it is cut. It is rough and fragile. The liver cell experiences balloon appearance changes ,spot death and fat transformation.5 The change in the expression level of liver PPARαmRNA and HNF4αmRNAThe expression of PPARαmRNA in the high fat feeding group become lessening compared to the comparison group notable (P<0.01) .The rosiglitazone interference group is higher than the fat feeding group , the difference is notable, (P<0.01) .The expression of HNF4αmRNA in the high fat feeding group become lessening compared to the comparison group ,the diffence is notable (P<0.01), the rosiglitazone interference group is higher than the fat feeding group, the difference is notable (P<0.05).Conclusion1 High fat feeding for 8 weeks can bring out mouse's insulin resistance. This model had the characteristics of normal insulin level in the condition of empty stomach , high blood insulin ,high blood lipid ,lowering sensitivity of insulin ,over weight.2 Insulin resistance can bring out nonalcoholic fatty liver disease and the lessening expression level of liver PPARαmRNA and HNF4αmRNA .The expression in the rosiglitazone interference group restores ,which shows both of them may participate in the case of nonalcoholic fatty liver disease . Rosiglitazone interference group has protective function in insulin resisitance and nonalcoholic fatty liver disease.
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