Naringenin protects against 1-methyl-4-phenylpyridinium- induced neuroinflammation and resulting reactive oxygen species production in SH-SY5Y cell line: An in Vitro model of parkinson's disease

Background: Parkinson's disease is a progressive neurodegenerative disorder which affects 1% of the population worldwide. It is well known that 1-methyl-4-phenylpyridinium (MPP+) selectively and potentially inhibit Complex I of the mitochondrial electron transport chain. This inactivation leads to the generation of reactive oxygen species (ROS), which in turn damage neurons. In addition, neuroinflammation plays a major role in neurodegeneration processes. Objective: In the present study, the effect of naringenin (NGN), on MPP+-induced neuroinflammation and ROS generation in SH-SY5Y cells were investigated. Materials and Methods: Cells were pretreated with (0.1% dimethyl sulfoxide) or NGN (25, 50, and 100 μm/mL) for 24 h, and then induced with 1 mM MPP+ for 15 min. Following overnight incubation, cells were harvested for ROS staining, gene expression of apoptotic markers such as B-cell lymphoma-2 (Bcl-2) and Bcl-2-associated X protein (Bax), inflammatory markers such as tumor necrosis factor-alpha (TNF-α), and nuclear factor-κB (NF-κB) and protein expression of neuronal markers such as dopamine transporter (DAT), tyrosine hydroxylase (TH), and α-synuclein (SYN). Results: In this study, NGN exhibited oxidative protection by decreasing ROS generation which is evidenced through significant regulation of oxidative stress markers. Likewise, NGN decreased TNF-α, Bax, and NF-κB and increased Bcl-2 gene expressions in MPP+-induced SH-SY5Y cells compared to normal SH-SY5Y cells. Further, NGN significantly and dose-dependently decreased SYN and increased DAT and TH levels in MPP+-induced SH-SY5Y cells in comparison to the normal cells. Conclusion: The results obtained from the present study revealed that NGN has the potential to encounter MPP+-induced dopaminergic degeneration through regulating ROS generation and neuroinflammation.