Vinpocetine Exerts Neuroprotective Effects via Downregulating α-Syn in Rotenone-induced Cellular Models of Parkinson’s Disease

Objective: Vinpocetine (Vinp), a derivative of alkaloid vincristine with anti-inflammatory and antioxidant effects, has been shown to have neuroprotective effects in Parkinson's disease (PD). Its role and mechanisms, however, are not fully understood. Therefore, the aim of this study was to investigate the effects and possible mechanisms of Vinp on PD cells. Methods: SH-SY5Y cells were treated with Vinp and then with rotenone to induce a cellular model of PD. The proliferation level and apoptosis rate of SH-SY5Y cells after different treatments were detected by MTT and flow cytometry assays, respectively. Western blot was used to determine the relative protein expression of α-Synuclein (α-Syn) in differently treated cells. Additionally, commercial kits and ELISA were used to determine oxidative stress-related indicators (superoxide dismutase [SOD], malondialdehyde [MDA], and reactive oxygen species [ROS]) and inflammatory factors (tumor necrosis factor α [TNF-α], interleukin-5 [IL-5], and interleukin-1β [IL-1β]) in SH-SY5Y cells after different treatments, respectively. Results: Vinp at different concentrations (5, 10, and 50 µM) had no significant effect on the proliferation and apoptosis of SH-SY5Y cells. For rotenone-induced SH-SY5Y cells, Vinp pretreatment could significantly reduce α-Syn expression, increased cell viability and decreased apoptosis, oxidative stress (downregulation of ROS and MDA levels and upregulation of SOD activity) and inflammation (increased levels of TNF-α, IL-5, and IL-1β). In contrast, overexpression of α-Syn in SHSY5Y cells with Vinp pretreatment and rotenone induction partially reversed the aforementioned protective effects of Vinp, causing a decrease in proliferation, an increase in apoptosis rate, inflammation, and oxidative stress. Conclusion: Vinp exerted neuroprotective effects by downregulating α-Syn to promote proliferation, inhibit apoptosis, and inhibit oxidative stress and inflammation in rotenone-induced SH-SY5Y cells.