| IntroductionGlucose transporter 4(GLUT4)was a kind of transmembrane protein,located in the insulin sensitived skeletal muscle tissue,adipose tissue and myocardial tissue, involving in the activity of glucose transporting as a kind of glucouse transportters. Large number of studies indicate that an important feature of type 2 diabetic mellitus(DM)was glucose-uptaking resistance which was stimulated by insulin.The change of expression and function of GLUT4 may be closely related to insulin resistance in skeletal muscle tissue and adipose tissue.By comparing the differences and variety of GLUT4 mRNA expression in skeletal muscle tissue and adipose tissue of rats in every group,this study explored the important molecular mechanism of type 2 diabetes.AimThis study was designed to investigate the difference,variety and influencing factors of GLUT4 mRNA expression in skeletal muscle tissue and adipose tissue of type 2 diabetic rat model.Material and methods1,Material33 healthy male Wistar rats weighing 180 -220 were obtained from Department of Animals,China medical university.2,Preparation of high-fat dietA constant high-fat diet of 100 g was prepared,containing 30 g lard,10 g sugar,3 g egg yolk. 3,Animal treatmentWistar rats were randomly divided into three groups-the control group,the type 2 diabetes group and the high-fat diet group.There were 10 rats in the control group,13 rats in the type 2 diabetes group and 10 rats in the high-fat diet group.The rats in the control group were fed with the normal diet for 10 weeks;the rats in the type 2 dibetes group were fed with the high-fat diet for 10 weeks and injucted low dose of STZ in the sixth week;the rats in the high-fat diet group were fed with the high fat diet for 10 weeks.4,Detection of the biochemical projectsWe detected the rats' serum total cholesterol,triglyceride,LDL-C,HDL-C,fasting blood glucose.Serum insulin samples were determined by radio-immunoassay.Then we caculated the insulin sensitivity index.5,Reverse transcription - polymerase chain reactionDetecting the expression of GLUT4 mRNA in skeletal muscle tissue and adpose tissue of rats in every group by RT-PCR methods,then the rate of the absorption value of GLUT4 and B-actin was used as relative expression level of GLUT4mRNA.6,Statistical analysisThe results were processed by SPSS 11.5 software.Differences between the groups were analyzed by the Analysis of Variance(ANOVA).Results1,Differences in body fat weight and serum lipid of rats in every groupThe weight of adipose tissue and the fat body mass ratio of the rats in the Type 2 diabetes group and the high-fat diet group were significantly higher than those in the control group(P＜0.01).TG,TC,and LDL-C of the rats in the Type 2 diabetes group and the high-fat diet group were significantly higher than those in the control group(P＜0.01),while HDL-C were lower(P＜0.01,＜0.05).2,Differences in fasting blood glucose,fasting serum insulin and insulin sensitivity index of rats in every group Hyperinsulinemia took place in the Type 2 diabetes group and the high-fat diet group(P＜0.01),and insulin sensitivity index decreased significantly in the Type 2 diabetes group and the high-fat diet group(P＜0.01).Compared with the control group fasting blood glucose of the Type 2 diabetes group increased significantly(P＜0.01).But there was no significant differences in fasting glucose between the high-fat diet group and the control group.3,The expression of GLUT4 mRNA in skeletal muscle tissue and adipose tissue of rats in every groupThe expression of GLUT4 mRNA in skeletal muscle tissue were higher than that in adipose tissue.The expression of GLUT4 mRNA in both of the Type 2 diabetes group and the high-fat diet group were lower than that in the control group whether in skeletal muscle tissue or adipose tissue(P＜0.01).ConclusionGLUT4 mRNA expressed in both skeletal muscle tissue and adipose tissue.The expression of GLUT4 mRNA in skeletal muscle was higher than that in adipose tissue. In the type 2 diabetic rat model,the expression of GLUT4 mRNA in the skeletal muscle tissue and adipose tissue were all lower than that of the control group.High-fat diet may cause the decreasement of the GLUT4 mRNA expression in skeletal muscle tissue and adipose tissue,which may lead the obstacles of glucose uptaking and utilization,then caused insulin resistance. |
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