Plasma TNF-? Improves Glucose Homeostasis In Diabetic Mice Independent With TNFRs And The Relationship Between MicroRNA-320 And Insulin Resistance

Objective:(1)The aim of the first part of the study is to explore the functional role of TNF-? in the regulation of glucose homeostasis.(2)The aim of the second part of the study is to explore the the relationship between microRNA-320 and insulin resistance,and the functional role of microRNA-320 in the process of pioglitazone regulate insulin resistance.Methods:(1)?Glucose tolerant test(GTT)and insulin tolerant test(ITT)were carried out to evaluate glucose homeostasis in TNFR1 and TNFR2 double knockout(TNFR1 and TNFR2 DKO)mice.? Plasma TNF-? in TNFR1 and TNFR2 DKO mice were measured,and evaluate the relationship between plasma TNF-? and glucose homeostasis.? We down-regulated the level of plasma TNF-? in TNFR1 and TNFR2 double knockout mice via AAV-shTNF-? injection,then detect the results of the GTT and ITT experiments.? We up-regulated the level of plasma TNF-? in ob/ob mice via AAV-TNF-? injection,then detect the change of glucose homeostasis,confirmed the functional role of plasma TNF-? in glucose homeostasis,and explore the mechanism of it.(2)?Using 3T3-L1 adipose cell set a model of insulin resistance,to detect cell glucose intake by glucose oxidase method,and detect the expression level changes of microRNA-320;?treat insulin resistant adipose cells with different concentration of pioglitazone(1uM,10uM,50uM,100uM,150uM),then detect the expression level changes of microRNA-320 at different time points(12h,24h,48h,72h).Results:(1)?Insulin resistance was dramatically improved in TNFR1 and TNFR2 double knockout mice;?The circulated TNF-? was upregulated in TNFR1 and TNFR2 double knockout mice;? The improvement of glucose homeostasis was suppressed when TNFR1 and TNFR2 DKO mice were administered AAV-shTNF-?;? The over-expression of plasma TNF-? could improve the results of GTT and ITT in ob/ob mice.(2)?After the differentiation of 3T3-L1 cells,the glucose intake in 3T3-L1 cells were decreased,and the microRNA-320 expression in cells were increased significantly;?After pioglitazone treatment,the glucose intake in adipose cells were increased,and the microRNA-320 expression in cells were decreased significantly.Conclusion:(1)?TNFR1 ? TNFR2 double knockout improved glucose Homeostasis in diabetic Mice;? plasma TNF-? play a key role in the regulation of glucose metabolism;? TNF-? supplies a benefit to reduce insulin resistance via a TNFRs-independent way in diabetic mice;? TNFR1 and TNFR2 may not be the only receptors for TNF-?.(2)?The microRNA-320 expression in insulin resistant fat cells were increased;? pioglitazone treatment can decrease the expression of microRNA-320 expression in insulin resistant fat cells,microRNA-320 may be a potential treat target in the process of insulin resistance treatment.