SD、E3与DA1U大鼠视网膜光损伤敏感性的差异研究

摘要

目的 比较SD、E3与DAIU大鼠视网膜光损伤敏感性,为构建不同品系大鼠视网膜光损伤模型和研究眼底色素抗光损伤保护视网膜的相关机制研究提供实验依据.方法 成年SD、E3、DAIU大鼠,雌雄随机选取,采用视网膜电图与HE染色分别检测正常情况下与光损伤后不同品系大鼠视网膜感光功能与组织形态变化,采用TUNEL染色观察光损伤后视网膜凋亡细胞的分布与数量.结果 正常状态下,SD大鼠色素上皮层、脉络膜层及E3大鼠色素上皮层均无色素分布,而E3大鼠脉络膜层、DAIU大鼠色素上皮层与脉络膜层有褐色色素分布；HE结果显示,在正常状态下,3种品系大鼠视网膜外核层厚度没有显著差异,而存光损伤条件下,SD大鼠视网膜各层细胞均严重受损；视网膜电图结果显示,在正常状态下,不同品系大鼠间视网膜电图视杆细胞反应b波振幅存在显著差异,E3大鼠最大混合反应a波及b波振幅与SD大鼠相比有显著差异,而在光损伤条件下,与SD大鼠相比,E3和DAIU大鼠视网膜电图a波与b波的波幅降幅显著减弱；TUNEL染色结果显示,与SD大鼠相比,E3与DA1U大鼠视网膜内核层及外核层凋亡细胞分布范围与数量均显著下降.结论 SD、E3与DAIU大鼠间存在视网膜色素分布与光损伤敏感性的差异,分布于脉络膜与色素上皮层的色素可能在大鼠抗视网膜光损伤过程中起到重要作用.%Objective To compare the sensitivity of light damage of retinas among SD, E3 and DA1U rats and provide experiment data for facilitating the model construction of light damage in retina and further study of the correlated mechanism between light damage and distribution of pigments in retina. Methods Elcctroretinogram (ERG) and HE staining were used to detect the functional and morphological changes in adult SD, E3 and DA1U rats before and after light damage. TUNEL staining was used to observe the distribution and the number of apoptotic retinal cells. Results In normal conditions, retinal pigment epithelium layer and choroid layer of SD rats and retinal pigment epithelium layer of E3 rats did not contain pigments, while choroid layer of E3 rats and retinal pigment epithelium layer and choroid layer of DA1U rats had brown granules. HE staining results revealed that these rat strains did not differ significantly in the thickness of outer nuclear layer (ONL) in normal conditions. After light damage, the cell layers of SD rat retinas vvere severely decreased. ERG results showed that in normal status, there were significant differences among different rat strains in the amplitude of b-wave of rod-ERG. SD and E3 rats differed significantly in the amplitude of both a-wave and b-wave of max-ERG. However, after light damage, the amplitude of a-wave and b-wave of max-ERG in E3 and DA1U rats decreased significantly as comparedwith SD rats. TUNEL staining showed that compared with SD rats, E3 and DA1U rats had the significantlyrndecreased scope and number of apoptotic cells in retinal ONL and inner nuclear layer (INL). Conclusion Retinalrnpigment distribution and sensitivity of light damage differ among SD, E3 and DA1U rats. The pigments in thernretinal pigment epithelium layer and the choroid layer may play an important role in protecting retinas from lightrndamage.