This study aimed to investigate the neuroprotective role of probiotics and 1,25-dyhydroxyvitamin D3 (calcitriol) against neurotoxicity on rotenone-induced human neuroblastoma cell line SH-SY5Y. Rotenone was administered to induce neurotoxic effects in SH-SY5Y cells. Calcitriol and probiotics were administered at different concentrations as pre- and post-treatment. The thiazolyl blue tetrazolium bromide (MTT) assay was performed to measure cell viability. Intracellular protein levels of antioxidant enzymes (protein tyrosine kinase (PTK), superoxide dismutase (SOD), glutathione peroxidase (GSH), glutathione reductase (GSR), and catalase (CAT)) were determined by the enzyme-linked immunosorbent assay (ELISA). Rotenone (150 nM) reduced (p < 0.001) cell viability compared to control cells. Single and combined pretreatments with probiotics (0.01 mg/ml, 0.05 mg/ml, and 0.1 mg/ml) and calcitriol (1.25 µM, 2.5 µM, and 5 µM) increased (p < 0.05) cell viability compared to rotenone group. In the pre- and post-treatment design, all treatment groups increased the SOD and GSH levels and decreased the GSR levels compared to rotenone. None of the pretreatments reversed the PTK levels (except probiotics: 0.01 mg/ml). Calcitriol (2.5 µM) increased the CAT levels in pretreatment design, and probiotics (0.05 mg/ml and 0.1 mg/ml) increased CAT levels in post-treatment design compared to rotenone group. Calcitriol and probiotics protect against rotenone-induced neurotoxicity in SH-SY5Y cells by decreasing reactive oxygen species (ROS) and increasing antioxidant enzyme parameters. These neuroprotective effects of calcitriol and probiotics against rotenone-induced dopaminergic neurotoxicity provide an experimental basis for their potential clinical use in the treatment of Parkinson's disease (PD).
Keywords: 1,25-dyhydroxyvitamin D3; Parkinson’s disease; SH-SY5Y cell-line; neuroprotective; neurotoxicity; probiotics.