Protective Effects of Nicotinamide Riboside on H₂O₂-induced Oxidative Damage in Lens Epithelial Cells

Purpose: To investigate the protective effects of nicotinamide riboside (NR) on oxidative damage in hydrogen peroxide (H₂O₂)-exposed human lens epithelial cell lines (SRA01/04) and the possible mechanisms underlying its protective effects.Materials and methods: SRA01/04 cells were divided into three groups: the control (CON) group, model (H₂O₂) group and treatment (NR+H₂O₂) group. Superoxide dismutase (SOD), catalase (CAT) and total glutathione (GSH) levels were detected to evaluate oxidative damage induced by different concentrations of H₂O₂ in SRA01/04 cells. After SRA01/04 cells were treated with NR and/or H₂O₂, cell viability was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and Hoechst staining, cell apoptosis was analysed using flow cytometry, reactive oxygen species (ROS) were measured with the DCFH-DA probe, and mitochondria were stained with MitoTracker to measure the mitochondrial membrane potential (MMP). In addition, western blotting was performed to detect the levels of proteins associated with apoptosis and related signalling pathways.Results: H₂O₂ induced oxidative damage in SRA01/04 cells by inhibiting the activity of SOD and CAT and reducing total GSH levels. Treatment of SRA01/04 cells with NR significantly increased cell viability and reduced cell apoptosis and ROS generation, whereas SOD and CAT activities and total GSH and MMP levels were improved by the NR treatment in an H₂O₂-exposed cell model. Furthermore, NR significantly inhibited the activation of the MAPK pathway but promoted activation of the JAK2/Stat3 pathway compared with the model group.Conclusions: NR may alleviate oxidative damage by targeting the MAPK and JAK2/Stat3 pathways in H₂O₂-treated SRA01/04 cells. NR may represent anovel drug for preventing or treating cataracts.