The Mechanism Of ZAG To Ameliorate Insulin Resistant HepG2 Cell By Enhancing Autophagy

Objective:1.To investigate the effect of ZAG on the expression of p-Akt Ser473 and GLUT4,significant signaling protein of insulin signaling pathway,in insulin resistant HepG2 cell.2.To examine the influence of ZAG on the expression of mTOR,which play a important role in regulating autophagy,and Atg7 and LC3-II,which are recongnized as representative protein of autophagy,in HepG2 cell with insulin resistance.3.To investigate whether the effect of ZAG in insulin signal transduction is related with autophagy.Methods:Methods in the literature were cited to induce insulin resistance in HepG2 cell^[1-3].The cell were divided into blank group,Control group,insulin resistance group（IR group）,ZAG group and ZAG+chloroguine group（ZAG+CQ group）.The Control group were cultured in RPMI 1640 medium containing 10%fetal bovine（FBS）;the other groups were cultured in RPMI 1640 medium containing 10%FBS and 10^﹣5mol/L insulin.After 24 hours of insulin resistance,ZAG group was added with a concentration of 25μg/mL ZAG,and ZAG+chloroguine group was added with a concentration of 25μg/mL ZAG and a concentration of 50μmol/L chloroguine for 24 hours.Before and after addition of ZAG,determin the glucose content in medium,and evaluate the glucose consumption.Extraction of protein from each group of HepG2 cell,using Western blot to detect the expression of p-Akt Ser473,GLUT4,mTOR,Atg7,LC3-II,and then conducting statistical analysis.Results:1.Compared with the Control group,the expression of p-Akt Ser473,GLUT4 of the IR group decreased significantly（P<0.05）;compared with the IR group,the expression of p-Akt Ser473,GLUT4 of the ZAG group increased significantly（P<0.05）;compared with the ZAG group,the expression of p-Akt Ser473,GLUT4 of the ZAG+CQ group decreased significantly（P<0.05）.2.Compared with the Control group,the expression of mTOR of the IR group increased significantly（P<0.05）,the expression of Atg7,LC3-II of the IR group decreased significantly（P<0.05）;compared with the IR group,the expression of mTOR of the ZAG group decreased significantly（P<0.05）,the expression of Atg7,LC3-II of the ZAG group increased significantly（P<0.05）;compared with the ZAG group,the expression of mTOR of the ZAG+CQ group increased,but it was not significant（P=0.550）,the expression of Atg7 of the ZAG+CQ group decreased significantly（P<0.05）,the expression of LC3-II of the ZAG+CQ group decreased,but it was not significant（P=0.055）.Conclusion:1.ZAG can improve insulin resistance by ameliorating impaired insulin signal pathway in insulin resistant HepG2 cell,and increasing glucose uptake.2.ZAG can improve the activity of autophagy in insulin resistant HepG2 cell.3.Inhibiting autophagy can weaken the effect of ZAG in increasing glucose consumption,improving insulin signal transduction and alleviating insulin resistance,and increase insulin resistance.4.ZAG reduce insulin resistance in various mechanisms.And its effect of enhancing autophagy activity and ameliorating insulin signal transduction may be one of molecular mechanisms to alleviate hepatic insulin resistance.5.ZAG alleviate insulin signal transdution of HepG2 cell,which may associated with the effect of ZAG in enhancing autophagy activity.