Defense mechanism for age-related macular degeneration.

锰超氧化物歧化酶（MnSOD）是一种天然存在的超氧化物清除剂，是活性氧的中间体之一。为了确定Mn SOD表达是否作为抵抗氧化挑战（例如强光暴露）的防御机制而增强，将大鼠暴露于强光（80勒克斯）下2周，（1，800 lux）24小时，然后再次进行循环光照，实验和对照（仅暴露于循环光）将眼睛摘除3小时，1，3，7，光刺激后14天，用抗大鼠MnSOD的兔抗血清检测MnSOD蛋白的表达，光刺激后14天，MnSOD蛋白的表达与对照组相比无显著差异。暴露组和对照组的外核层厚度。正常视网膜色素上皮（RPE）细胞和光感受器内节均被Mn SOD标记，实验动物光刺激后3 h和1d Mn SOD标记消失，光刺激后3、7、14 d在RPE细胞和14 d在光感受器内节重新表达Mn SOD。提示视网膜可能具有抗光损伤的保护作用，Mn-SOD可能在其中起重要作用。

Manganese superoxide dismutase (Mn SOD) is a naturally occurring scavenger of superoxide, one of reactive oxygen intermediates. To determine if Mn SOD expression is enhanced as a defensive mechanism against oxidative challenges, such as intense light exposure, rats were exposed to cyclic tight (80 lux) for 2 weeks, intense light (1,800 lux) for 24 hours, and then again to cyclic light, Experimental and control (exposed to cyclic light only) eyes were enucleated 3 hours, 1, 3, 7, and 14 days after light challenge and protein expression was examined immunohistochemically using rabbit antisera against rat Mn SOD.There was no significant difference between the light-exposed and the control groups in the thickness of the outer nuclear layers. Both retinal pigment epithelial (RPE) cells and photoreceptor inner segments in the normal retina were labeled for Mn SOD.After Mn SOD labeling was lost 3 hours and day 1 after light challenge, it was re-expressed in the RPE cells days 3, 7, and 14 and in the photoreceptor inner segments the day 14 after light challenge in experimental animals. These results suggest that the retina might have a protective potential against light damage, in which Mn-SOD may play some important role.