Oxidative stress and inflammation: hypothesis for the mechanism of aging

Oxidative stress due to free radicals is related to the pathogenesis of many chronic disorders including cancer, inflammation, and neurological diseases. Oxidative stress such as aging and light exposure is also considered to be associated with age-related macular degeneration and cataract. The ocular surface is chronically exposed to oxidative stress including ultraviolet light, the oxygen in air, and changes in oxygen pressure due to blinking. We demonstrated that a rat dry eye model with a jogging board showed corneal epithelial disoders and elevated levels of oxidative stress, suggesting that the pathogenesis of epithelial disorders in dry eye with low frequency of blinking is related to oxidative stress. Next, using a model of laser-induced choroidal neovascularization (CNV), we showed that angiotensin receptormediated inflammation is required for the development of CNV. We also demonstrated that mice deficient in superoxide dismutase (SOD) showed typical clinical features of AMD. Finally, we proposed our thoughts about regenerative medicine, that is, to maintain quiescent stem cells, we have to regulate the aging of stem cells.