The Gene Expressions Of Visfatin And Adiponectin In The Adipose Tissues And Their Correlations To Insulin Resistance In Rats With Steroid Diabetes

Objective: We studied the different gene expressions of visfatin and adiponectin in visceral and subcutaneous adipose tissues in steroid diabetic rats and normal ones. Then by exploring their correlations with weight, Lee's index, blood glucose, insulin, blood lipids and Homa insulin resistance index, we analyzed the effect and possible mechanism of visfatin and adiponectin in insulin resistance.Methods: (1) The male adult Spratue-Dawley(SD)rats were injected intraperitoneally with dexamethasone (0.1mg/100g, qd) for three weeks. Then,the SD rats with fasting blood glocose (FBG)higher than 13.8 mmol/L were considered as steroid diabetic rats. Meanwhile, the normal rats were injected intraperitoneally with 0.9% NaCl in the same way for comparison to examine the changes of steroid diabetic rat group in weight, Lee's index, endo-abdominal fat weight, fat index, triglycerides(TG), total cholesterol(TC), low-density lipoprotein cholesterol(LDL-C), high-density lipoprotein cholesterol (HDL-C), fasting serum insulin (FINS) and fasting blood glucose. (2) The gene expressions of visfatin and adiponectin in the abdominal adipose tissues were detected through fluorescence real-time quantitative PCR.Results:(1)The steroid diabetic rats induced by dexamethasone had higher FBG, FINS, insulin resistance index (HOMA-IR),TG , TC, LDL-C than those of the control, but lower weight, lee's index than those of the control.(2)Compared with the control group, expression of visfatin mRNA in the visceral adipose tissue(VAT) increased in rats with steroid diabetes, whereas expression of adiponectin mRNA in the visceral adipose tissue decreased. The expressions of visfatin or adiponectin mRNA in subcutaneous adipose tissue(SAT) displayed no significant changes in steroid diabetic rats compared with control group. (3)VAT visfatin mRNA expression was positively correlated with FBG( r=0.378, P<0.05 ), but not with HOMA-IR. SAT visfatin mRNA expression was not correlated with FBG, FINS, HOMA-IR,TG,TC, LDL-C, HDL-C, weight, lee's index. In a multiple linear regression analysis, only FBG was independently correlated with VAT visfatin mRNA expression. (4)VAT adiponectin mRNA expression was correlated negatively with FBG, FINS and HOMA-IR(r=-0.425;-0.457;-0.512; P<0.05). SAT adiponectin mRNA expression was not correlated with FBG, FINS, HOMA-IR,TG, TC, LDL-C, HDL-C, weight, lee's index. In a multiple linear regression analysis, FBG,FINS, HOMA-IR were correlated with VAT adiponectin mRNA expression.Conclusions: (1)The steroid diabetic rat model is developed successfully, which has a series of characters with the high level of FBG, FINS, HOMA-IR, TG, TC, LDL-C. (2)Our data show that compared with normal rats,there is up-regulation in VAT visfatin mRNA, down-regulation in VAT adiponectin mRNA and no significant change in SAT visfatin and adiponectin mRNA expressions in steroid diabetic rats. It suggests that visceral adipose tissue plays more important role than subcutaneous adipose tissue in the development of steroid diabetes and insulin resistance. Up-regulation in VAT visfatin mRNA in steroid diabetic rats may be related to the accumulation of visceral fat,but not to insulin resistance. Expression of VAT adiponectin mRNA is closely related to insulin resistance. The level of adiponectin mRNA expression in visceral adipose tissue seems to be an important parameter of insulin resistance.