Effects Of Exendin-4upon Methylglyoxal-induced Oxidative Stress In Pc12Cell

Background and aims:Diabetes related neurodegenerative disease is closely related to oxidative stress. High blood glucose promotes a large number accumulation of methylglyoxal. The goal of this study was to investigate the mechanism of oxidative stress in PC12cells induced by methylglyoxal, and study whether Exendin-4, a glucagon-like peptide-1receptor agonist, could influence oxidative stress induced by methylglyoxal in PC12cells and its underlying mechanisms. Materials and methods:Cultured PC12cells were induced by methylglyoxal at concentration ranging from0to2.0mmol/l for12-48h. MTT assay was used to measure the cell viability. On this basis, PC12cells were exposed to0.75mmol/l methylglyoxal for24h with pretreatment of Exendin-4for24h, and pretreatment of N-acetylcysteine for24h as positive control, MTT assay was used to measure the cell viability, Fluorescence enzyme-labeled instrument was used to detect the express of reactive oxygen species, xanthine oxidase method was used to detect the activity of superoxide dismutase. With pretreatment of100nmol/L Exendin-4or lOmmol/L N-acetylcysteine for24h, expression of P-I κ, B-α, IκB-α were detected by western Blot after PC12cells were exposed to0.75mmol/l methylglyoxal for1h.Results: Following methylglyoxal administration, the viability of PC12cells was gradually reduced in a dose-and time-dependent manner. Pretreatment with Exendin-4for24hours, the viabilities of PC12cells were gradually increased along with the increasing of Exendin-4from25nmol/L to100nmol/L. But it did not keep on increasing when Exendin-4concentration rising from100nmol/L to200nmol/L furthermore. With the pretreatment of N-acetylcysteine (NAC)for24hours as the positive control, Compared with methylglyoxal-alone group, the express of ROS in the Exendin-4pretreatment group was reduced by65.30%(p<0.01), and the expression of ROS in the NAC pretreatment group was reduced by107.40%(p<0.01); the activity of SOD in the Exendin-4pretreatment group was increased by5.30U/mgprot (p<0.01), and the activity of SOD in the NAC pretreatment group was increased by8.53U/mgprot (p<0.01); the ratio of P-I κB-α/Iκ B-α in the Exendin-4pretreatment group was reduced by25.50%(p<0.01), and the ratio of P-I κ B-α/I κ B-α in the NAC pretreatment group was reduced by35.14%(p<0.01).Conclusion:This study demonstrates that Exendin-4could increase the viabilities of PC12cells and protect PC12cells from oxidative stress induced by methylglyoxal. Our data suggests that the mechanism may involve suppress the activation of protein Iκ B-α.