Circadian-dependent retinal light damage in rats.

摘要: RESULTS. When dark-adapted, cyclic light‐reared or dark-reared rats were exposed to intense light during normal nighttime hours (2000 ‐ 0800) the loss of rhodopsin photoreceptor cell DNA was approximately twofold greater than that found in day (0800 ‐2000). The relative degree damage susceptibility persisted after dark adaptation for up 3 additional days. For reared a reversed cycle, light-induced also reversed. Longer duration treatments revealed dim light‐ three- fourfold more susceptible at 0100 1700 and animals susceptible. Intense exposure resulted retinal fragmentation earlier appearance apoptotic ladders 1700. extent correlated with an induction HO-1 mRNA reduction IRBP transcription. Antioxidant treatment DMTU effective preventing when given before but not onset light. CONCLUSIONS. These results confirm work showing night rather extend those findings by demonstrating single, relatively short, causes circadian-dependent, oxidatively induced cells. cells is preceded alterations transcriptional events retina within photoreceptors. expression profile intrinsic factor(s) appears be important determining susceptibility. (Invest Ophthalmol Vis Sci. 2000;41:3694 ‐3701)