Alpha-lipoic acid alleviates the 6-OHDA-induced SH-SY5Y cell damage by inhibiting autophagy via AMPK/mTOR pathway

Abstract

Objective To investigate the effects of α-lipoic acid(ALA)on 6-hydroxydopamine(6-OHDA)-induced autophagy in human neuroblastoma(SH-SY5Y)cells and its possible mechanisms. Methods SH-SY5Y cells were divided into 5 groups: blank control group(group A), ALA group(group B), 6-OHDA group(group C), ALA+ 6-OHDA group(group D), and rapamycin(RAPA)group(group E). The cell viability, cell apoptosis, and oxidative stress were assayed and analyzed in A-D group.The expression of autophagy-related proteins LC3-Ⅱ, AMP-activated protein kinase(AMP-K), phosphorylated AMPK(p-AMPK), the mammalian target of rapamycin(mTOR)and p-mTOR were detected by Western blot in A-E group. Results Compared with the blank control group, the 6-OHDA group significantly reduced the cell viability(P<0.01)and p-mTOR protein expression(P<0.05), and increased the cellular apoptosis rate(P<0.01), oxidative stress level(P<0.01), LC3-Ⅱ protein expression(P<0.05, with the highest level at 6 h after treatment), and p-AMPK protein expression(P<0.05). There was no significant difference in these indices between ALA group and the blank control group.Compared with 6-OHDA group, ALA+ 6-OHDA group showed that the cell viability(P<0.01)and p-mTOR protein expression(P<0.05)were increased, while the cellular apoptosis rate(P<0.01), oxidative stress level(P<0.01), LC3-Ⅱ protein expression(P<0.05), and p-AMPK protein expression(P<0.05)were decreased. Conclusions The 6-OHDA can induce oxidative stress and autophagy in SH-SY5Y cells and decrease the cell viability.ALA can alleviate the 6-OHDA-induced cell injury possibly by inhibiting autophagy via AMPK/mTOR pathway. Key words: Parkinson's disease; Autophagy; α-lipoic acid; Oxidative stress