Department of Anatomy, All India Institute of Medical Sciences, New Delhi, India.
Photochem Photobiol. 2020 Sep;96(5):1061-1073. doi: 10.1111/php.13244. Epub 2020 Apr 30.
Light insult causes photoreceptor death. Few studies reported that continuous exposure to light affects horizontal, Müller and ganglion cells. We aimed to see the effect of constant light exposure on bipolar and amacrine cells. Adult Sprague-Dawley rats were exposed to 300 or 3000 lux for 7 days in 12-h light: 12-h dark cycles (12L:12D). The latter group was then exposed to 24L:0D for 48 h to induce significant damage. The same animals were reverted to 300 lux and reared for 15 days in 12L:12D cycles. They were sacrificed on different days to find the degree of retinal recovery, if any, from light injury. Besides photoreceptor death, continuous light for 48 h resulted in downregulation of parvalbumin in amacrine cells and recoverin in cone bipolar cells (CBC). Rod bipolar cells (RBC) maintained an unaltered pattern of PKC-α expression. Upon reversal, there were increased expressions of parvalbumin in amacrine cells and recoverin in CBC, while RBC showed an increasing trend of PKC-α expression. The data show that damage in bipolar and amacrine cells after exposure to intense, continuous light can be ameliorated upon reversal to normal LD cycles to which the animals were initially acclimated to.
光损伤导致光感受器死亡。少数研究报告称，持续暴露于光线下会影响水平细胞、Müller 胶质细胞和节细胞。我们旨在观察持续光照对双极细胞和无长突细胞的影响。成年 Sprague-Dawley 大鼠在 12 小时光照：12 小时黑暗（12L:12D）周期中分别暴露于 300 或 3000 lux 下 7 天。后者随后暴露于 24L:0D 中 48 小时以诱导显著损伤。相同的动物被恢复到 300 lux 并在 12L:12D 周期中饲养 15 天。它们在不同的日子被处死，以确定光损伤后的视网膜恢复程度（如果有）。除了光感受器死亡之外，持续 48 小时的光照还导致无长突细胞中的钙结合蛋白 parvalbumin 和视锥双极细胞（CBC）中的 recoverin 下调。杆状双极细胞（RBC）保持不变的 PKC-α 表达模式。恢复后，无长突细胞中的 parvalbumin 和 CBC 中的 recoverin 表达增加，而 RBC 中 PKC-α 的表达呈增加趋势。数据表明，在强烈、持续的光照下，双极细胞和无长突细胞的损伤在恢复到动物最初适应的正常 LD 周期时可以得到改善。
