Resolvin D1 Improves Insulin Resistance In HepG2 Cells Induced By Palmitic Acid

Purpose:Resolvin D1(RvD1)as a specialized pro-resolving mediator derived from DHA(Docosahexaenoic Acid),one of n-3 polyunsaturated fatty acids,has anti-inflammatory and immunomodulatory effects.Animal experiments had shown that RvDl can improve glucose tolerance and insulin resistance in Adipose tissue.Our experiment used palmitic acid(PA)-induced insulin resistant HepG2 cells as a model to compare the effects of different concentrations of RvD1 on glucose uptake,IRS-1/PI3K/AKT protein expression,and mRNA expression of related genes.Therefore,this experiment tried to investigate whether RvD1 has the effect on improving insulin resistance as well as underlying molecular mechanism.Methods:The experiment had established BSA control group,PA induced model group and RvD1 intervention group.HepG2 cells were cultured in DMEM containing 0.25 mmol/L PA and 0.25%BSA for 24 hours to establish an IR-HepG2 cell model.Effect of PA and RvDl on cell viability was detected by CCK-8.And then IR-HepG2 cells were cultured in DMEM containing 2 nmol/L,5 nmol/L,10 nmol/L,or 20 nmol/L RvD1 for 24 hours.GOD-POD method was used to determine glucose consumption of cells.The protein expression levels of IRS-1,p-IRS-1(ser307),PI3K p85,AKT,and p-AKT(ser473)were detected by Western Blot;the mRNA expression levels of IRS-1,INSR,PI3K,AKT,and GLUT2 genes were detected by RT-PCR.Results:1.Compared with BSA control group,the model group had significantly lower glucose consumption(p<0.001).And p-AKT(ser473)expression level(p<0.05)and the ratio of p-AKT/AKT(p<0.01)were both decreased,p-IRS-1(ser307)expression level was increased(p<0.01).The mRNA expression levels of IRS-1,INSR,PI3K,AKT and GLUT2 genes were decreased in model group.2.The results of CCK-8 had showed that the HepG2 cells incubated with 2-20nmol/L RvD1 for 24h could survivel well.RvD1(2nmol/L,5nmol/L,10nmol/L and 20nmol/L)could effectively improve the glucose uptake of IR-HepG2 cells.Compared with the model group,the expression of p-AKT(p<0.05)and the ratio of p-AKT/AKT(p<0.05)were increased after RvD1 treatment.The mRNA expression level of GLUT2 gene was increased(p<0.05),and expression levels of other proteins and genes had not changed significantly after RvD1 treatment.Conclusions:RvD1 could improve the glucose uptake of palmitic acid-induced IR-HepG2 cells,increase the phosphorylation of AKT and mRNA expression of GLUT2 gene,but other proteins on IRS-1/PI3K/AKT pathway had not changed significantly,and expression of other genes had not changed significantly either.