Lipoic acid inhibits nerve cell apoptosis in rats with Parkinson's disease via Erk signaling pathway

Abstract

Purpose: To investigate the effect of lipoic acid on nerve cell apoptosis in rats with  Parkinson's disease via the extracellular signal-regulated kinase (ERK) signaling pathway.Methods: A total of 36 rats were randomly divided into normal group (n = 12), Parkinson's disease model group (n = 12) and lipoic acid group (n = 12). The neuronal morphology was examined by means of Nissl staining, while cell apoptosis was assessed by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay.Results: The neurons were severely damaged in model group, while neuronal morphology and structure were ameliorated in lipoic acid group when compared with those in model group. The p-ERK was lowered significantly (p < 0.05) in model group and lipoic acid group compared with that in normal group. Levels of mRNA, caspase-3 and Bax increased significantly, while Bcl-2 decreased in model group and lipoic acid group when compared with those in normal group (p < 0.05). Lipoic acid treatment significantly reduced mRNA expression of caspase-3 and Bax, but increased Bcl-2 compared with model group. Furthermore, ELISA results indicate that model and lipoic acid groups exhibited raised caspase-3 and Bax but significantly reduced Bcl-2 levels, compared with normal group. The results also showed that the apoptosis was higher in the other two groups than in normal group; on the other hand, it was significantly lower in lipoic acid group than in model group (p < 0.05).Conclusion: Lipoic acid inhibits nerve cell apoptosis in rats with Parkinson's disease by up-regulating ERK signaling pathway. Therefore, lipoic acid is a potential neuroprotective agent for the management of Parkinson’s disease.