Hydrogen Sulfide Protects Retinal Pigment Epithelial Cells from Oxidative Stress-Induced Apoptosis and Affects Autophagy

Age-related macular degeneration (AMD) is a major cause of visual impairment and blindness among the elderly. AMD is characterized by retinal pigment epithelial (RPE) cell dysfunction. However, the pathogenesis of AMD is still unclear, and there is currently no effective treatment. Accumulated evidence indicates that oxidative stress and autophagy play a crucial role in the development of AMD. H2S is an antioxidant that can directly remove intracellular superoxide anions and hydrogen peroxide. The purpose of this study is to investigate the antioxidative effect of H2S in RPE cells and its role in autophagy. The results show that exogenous H2S (NaHS) pretreatment effectively reduces H2O2-induced oxidative stress, oxidative damage, apoptosis, and inflammation in ARPE-19 cells. NaHS pretreatment also decreased autophagy levels raised by H2O2, increased cell viability, and ameliorated cell morphological damage. Interestingly, the suppression of autophagy by its inhibitor 3-MA showed an increase of cell viability, amelioration of morphology, and a decrease of apoptosis. In summary, oxidative stress causes ARPE-19 cell injury by inducing cell autophagy. However exogenous H2S is shown to attenuate ARPE-19 cell injury, decrease apoptosis, and reduce the occurrence of autophagy-mediated by oxidative stress. These findings suggest that autophagy might play a crucial role in the development of AMD, and exogenous H2S has a potential value in the treatment of AMD.