Expression and role of suppressor of cytokine signaling 3 in liver and skeletal muscle of diabetes lab rats

Objective To observe the expression of suppressorsofcytokinesignaling3(SOCS-3)in liver and skeletal muscleofrat model of type 2 diabetes and to investigate its role in the pathogenesis of insulin resistance. Methods Fortymale SD rats were randomly divided into two groups.Thecontrol group(20 malerats) were fed with standard diet,while thediabetesgroup(20 malerats)were fed with high sucrose-fat diet for 4 weeks and then injected intraperitoneally with streptozotocin(STZ),16 malerats satisfied the case definitionof type-2 diabetes.Thelevel of serum insulin wasmeasured with radioimmunity,the level of glucose wasmeasured withglucose oxidase method,and the insulin sensitivity index and insulin resistance index were calculated.Thelevelsof SOCS-3 mRNA and SOCS-3 protein expression in liver and skeletal musclewere detected by real-time PCR and Western blot.The data were analyzed by T-test and Pearson linear correlation analysis. Results ①Normal SD rats fed with high sucrose-fat diet for 4 weeks and then injectedintraperitoneally with STZ could establish type-2 diabetes model.②Compared withcontrol group,the levelsof serum insulin andglucose,andthe insulin resistance index in diabetes group were increasedsignificantly(P＜0.05),while the insulin sensitivity index was decreased significantly(P＜0.05).③The SOCS-3 mRNA and protein expression level of liver and skeletal muscle in the diabetes group were higher than in thecontrol group(P＜0.05).④The SOCS-3 protein expression level of liver and skeletal muscle in the diabetes groupwere higher than in the control group(P＜0.05).⑤The SOCS-3 mRNA and protein expression of liver and skeletal musclewere positively correlated with the levelsof serum insulinin diabetes group(r=0.813，0.871，0.851，0.874,P＜0.05). Conclusion The increased expression of SOCS-3 may act as the negative factors of insulin signaling pathway and may play an important role in insulin resistance.