Investigation of neuroprotective effects of newly synthesized benzimidazolium salt against neurotoxicity in differentiated SH-SY5Y neuronal cells.

Neurodegenerative diseases (ND) are a group of neurological disorders characterized by various pathological features such as selective neuronal loss, chronic inflammation, and aggregation of specific proteins. This study aimed to investigate the possible protective effects of newly synthesized benzimidazolium salt (BS) against HO-induced oxidative stress in differentiated SH-SY5Y cells. Firstly, retinoic acid was applied to SH-SY5Y cells to obtain mature neurons. Then, a toxicity model was created by HO treatment of neuron-like differentiated SH-SY5Y (d- SH-SY5Y) cells. Survival rates of d-SH-SY5Y cells were determined using the 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) method. In addition, pro-inflammatory cytokine (tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), interleukin-6 (IL-6) levels were determined by ELISA method, while gene expression levels of apoptotic markers (Bax, Bcl-2, caspase-3 and caspase-8) were determined by RT-QPCR method. In addition, the effect of BS on neurite length in these cell groups was evaluated through morphological observations. According to our results, BS showed neuroprotective effect by increasing cell viability against HO-induced neurotoxicity in d-SH-SY5Y cells (p < 0.01). BS pretreatment provided HO-induced Bcl-2 up-regulation, Bax down-regulation, caspase-3 activation and caspase-8 inhibition. In addition, BS supported the decrease in TNF-α, IL-1β and IL-6 protein levels. This study demonstrated for the first time that BS exhibited potential neuroprotective effects on HO-induced neuronal damage by attenuating inflammation and apoptosis. These findings suggest that BS may be considered a promising candidate in preventing and treating oxidative stress-mediated neurodegenerative diseases.