Xie Zhenggao, Wu Xingwei, Gong Yuanyuan, Song Yi, Qiu Qinghua, Li Caihong
Department of Ophthalmology, The First Affiliated Hospital, Shanghai Jiao Tong University, Wujin Road 85, Shanghai 200080, China.
Curr Eye Res. 2007 May;32(5):471-9. doi: 10.1080/02713680701257621.
To investigate the effect of Ginkgo biloba extract EGb 761, a free-radical scavenger, on the antioxidation capability of retina after light-induced retinal damage in rats in an attempt to understand the mechanism by which EGb 761 protects the photoreceptors after light-induced retinal damage.
Seventy-two female Sprague-Dawley (SD) rats were evenly randomized into normal control group (NC group), light-induced retinal damage model group (M group), model + normal saline group (MN group), and model + EGb 761 group (ME group). Light-induced retinal damage model was induced via exposure to white light at 2740 +/- 120 lux for 6 hr. Rats in MN group and ME group were intraperitoneally injected daily with normal saline and 0.35% EGb 761 (100 mg/kg), respectively, 1 week before and 2 weeks after light exposure. The levels of malondialdehyde (MDA), total superoxide dismutase (T-SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) in the retinal tissues were determined 24 hrs after light exposure; photoreceptor apoptosis was detected 4 days after light exposure. One and 2 weeks after light exposure, histopathologic examination was carried out, and the outer nuclear layer (ONL) thickness (number of nuclei) in the superior and inferior retina was counted.
Twenty-four hours after exposure, the MDA levels in the other three groups were significantly higher than that in the NC group (p < 0.05); those in the M and MN groups were similar to each other (p > 0.05); and that of the ME group was significantly lower than those in the M and MN group (p < 0.05). The activities of T-SOD, GSH-Px, and CAT were similar in the M and MN groups (p > 0.05); the activities in the M and MN groups were significantly lower than those in the NC and ME groups (p < 0.05); and the activities in the ME group were significantly higher than those in the M and MN groups (p < 0.05). Four days after exposure, the apoptotic photoreceptors within the ONL in the ME group were obviously fewer than those in the M and MN groups. One week and 2 weeks after exposure, the ONL thickness (number of nuclei) in the ME group was more than that in the M and MN groups but less than that in the NC group.
Intraperitoneal injection of EGb 761 can enhance the antioxidation ability of retina and partially inhibit the apoptosis of photoreceptors, thus exert a protective effect on photoreceptors.
研究自由基清除剂银杏叶提取物EGb 761对大鼠光诱导视网膜损伤后视网膜抗氧化能力的影响，以探讨EGb 761在光诱导视网膜损伤后保护光感受器的机制。
将72只雌性Sprague-Dawley（SD）大鼠平均随机分为正常对照组（NC组）、光诱导视网膜损伤模型组（M组）、模型+生理盐水组（MN组）和模型+EGb 761组（ME组）。通过在2740±120勒克斯的白光下照射6小时诱导光诱导视网膜损伤模型。MN组和ME组大鼠在光照前1周和光照后2周每天分别腹腔注射生理盐水和0.35% EGb 761（100毫克/千克）。光照24小时后测定视网膜组织中丙二醛（MDA）、总超氧化物歧化酶（T-SOD）、谷胱甘肽过氧化物酶（GSH-Px）和过氧化氢酶（CAT）的水平；光照4天后检测光感受器凋亡情况。光照1周和2周后进行组织病理学检查，计数视网膜上下方外层核层（ONL）厚度（细胞核数量）。
照射24小时后，其他三组的MDA水平均显著高于NC组（p<0.05）；M组和MN组的MDA水平相似（p>0.05）；ME组的MDA水平显著低于M组和MN组（p<0.05）。M组和MN组的T-SOD、GSH-Px和CAT活性相似（p>0.05）；M组和MN组的活性显著低于NC组和ME组（p<0.05）；ME组的活性显著高于M组和MN组（p<0.05）。照射4天后，ME组ONL内凋亡的光感受器明显少于M组和MN组。照射1周和2周后，ME组的ONL厚度（细胞核数量）大于M组和MN组，但小于NC组。
腹腔注射EGb 761可增强视网膜的抗氧化能力，部分抑制光感受器凋亡，从而对光感受器发挥保护作用。
