The Effect Of PPAR-γ Agonist With Different Glucose On Apoptosis And IRS-2, FOXO1 MRNA Expression In Islet β-Cell Line NIT-1

Objective To study apoptosis and the expression of IRS-2, FOXO1 mRNA in vitro isletβ-cell line NIT-1 cells, under the conditions of different concentrations of glucose and the intervention of rosiglitazone.Methods The pancreaticβcell line NIT-1 were cultured in 24-hole plate by 5×104 cells / hole for 48 hours,then randomly assigned to each treatment group: 5.6 group (containing glucose 5.6mmol / L), 11.1 group ( 11.1 mmol / L), 16.7 group (16.7mmol / L), 22.5 group (22.5mmol / L) and 27.6 group (27.6mmol / L) and then incubated for 24 hours, within each group were randomly divided into non-rosiglitazone intervention ( the control group) and rosiglitazone intervention group (ie, intervention group which added 10-7 mol / L,10-6 mol / L ,10-5 mol / L rosiglitazone).To 48h, then collected cell and culture supernatants. Detecting insulin levels by radioimmunoassay, cell apoptosis by immunofluorescence staining, the expression in mRNA lever of FoxO1mRNA and IRS-2mRNA of each group by Real-time PCR relative quantification method . Results (1) With different concentrations of rosiglitazone intervention, 10-5mol / L rosiglitazone concentration of the intervention group has the highest insulin levels in the same glucose concentration.The results showed insulin secretion gradually decreased along with lowering levels of rosiglitazone(p < 0.05), 10-7mol/L group and non-rosiglitazone group showed no significant difference (p> 0.05). Whether or not rosiglitazone, each sugar concentration cell apoptosis showed the same trend, that is, with the sugar concentration increased, the cell apoptosis. With the intervention of 10-5mol / L of rosiglitazone , 16.7group,22.5 group and 27.6 group apoptosis reduced significantly (p <0.05). The other groups after rosiglitazone to apoptosis show no significant difference (p> 0.05).(2) With the intervention of 10-5mol / L of rosiglitazone and under the conditions of the same glucose concentration, the expression of IRS-2mRNA of rosiglitazone intervention group was significantly higher than the control group (p<0.05).Different concentrations of glucose group, whether or not rosiglitazone, the group IRS-2 mRNA expression showed the same trend, that is, 11.1 group IRS-2mRNA expression is the highest levels, followed by decrease with the increase of glucose concentration.(3) With the intervention of 10-5mol / L of rosiglitazone ,22.5 group,27.6 group FoxO1 mRNA expression in rosiglitazone intervention group were significantly lower than the control group (p<0.05). Different concentrations of glucose group, whether or not rosiglitazone, FoxO1 mRNA expression in each group showed the same trend, that with the increase of glucose concentration (p <0.05). Conclusion High glucose can Up FoxO1mRNA expression and inhibit IRS-2 mRNA expression in pancreaticβcells,thus impede proliferation and induce apoptosis of pancreatic islet cells. Rosiglitazone may act on pancreaticβcells through direct or indirect regulation FoxO1mRNA expression, IRS-2 mRNA expression in pancreaticβcells to regulate the proliferation and function, inhibition of apoptosis; prompted by regulating FoxO1mRNA expression, IRS-2 mRNA in expression, which can effectively affect the isletβcell function and cell proliferation, apoptosis.