Zhang Xuan, Hu Yizhen
Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
Department of Ophthalmology, Children's Hospital of Chongqing Medical University, Chongqing, 400014, China.
J Huazhong Univ Sci Technolog Med Sci. 2012 Aug;32(4):613-619. doi: 10.1007/s11596-012-1006-6. Epub 2012 Aug 11.
This study investigated the inhibitory effect of grape seed proanthocyanidin extract (GSPE) on selenite-induced cataract formation in rats and the possible mechanism. Eighty 8-day-old Sprague-Dawley rats were divided randomly into 5 groups: control group, model group, three GSPE groups (low dose, medium dose and high dose). Control group received subcutaneous injection of physiological saline. Model group was given subcutaneous injection of sodium selenite (20 μmol/kg body weight) on the postpartum day 10, and once every other day for consecutive three times thereafter. GSPE treated groups were respectively administered GSPE at doses of 50, 100, and 200 mg/kg body weight intragastrically 2 days prior to the selenite injection (that was, on the postpartum day 8), and once daily for fourteen consecutive days thereafter. The opacity of lenses was observed, graded and photographed under the slit lamp microscopy and the maximal diameter of the nuclear cataract plaques was measured. The lenses were analyzed for superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-PX), malondialdehyde (MDA), calcium (Ca(2+)), nitric oxide (NO) and anti-hydroxyl radical ability (anti-OH(-)). The histomorphology of lenses was observed with HE staining under a light microscope. The levels of calpainII, and iNOS protein and mRNA expression in lenses were detected by using immunohistochemistry and real-time quantitative RT-PCR. The results showed subcutaneous injection of sodium selenite led to severe nuclear cataract in model group, and the achievement ratio of model group was 100%. As compared with model group, the degree of lenses opacity and the maximal diameter of nuclear cataract plaques were significantly reduced in GSPE-treated groups. Moreover, we observed selenite treatment caused a significant decrease in the activities of antioxidative enzymes (SOD, CAT, GSH-PX) and anti-OH(-) ability, accompanied by a significant increase in the levels of MDA, NO, Ca(2+) as well as iNOS, and calpainII protein and mRNA expression. Administration of GSPE could dose-dependently preserve the activities of these antioxidative enzymes and anti-OH(-) ability, accompanied by a significant reduction in the levels of MDA, NO, Ca(2+) as well as iNOS, and calpainII protein and mRNA expression. These results suggested that GSPE markedly prevented selenite-induced cataract formation probably by suppressing the generation of lipid peroxidation and free radicals as well as the activation of iNOS, and calpainII in the lenses.
本研究探讨了葡萄籽原花青素提取物（GSPE）对亚硒酸盐诱导的大鼠白内障形成的抑制作用及其可能机制。80只8日龄的Sprague-Dawley大鼠随机分为5组：对照组、模型组、三个GSPE组（低剂量、中剂量和高剂量）。对照组皮下注射生理盐水。模型组在产后第10天皮下注射亚硒酸钠（20 μmol/kg体重），此后每隔一天注射一次，连续注射三次。GSPE处理组在注射亚硒酸钠前两天（即产后第8天）分别以50、100和200 mg/kg体重的剂量灌胃给予GSPE，此后连续14天每天给药一次。在裂隙灯显微镜下观察晶状体混浊情况，进行分级并拍照，测量核性白内障斑块的最大直径。分析晶状体中的超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、谷胱甘肽过氧化物酶（GSH-PX）、丙二醛（MDA）、钙（Ca(2+)）、一氧化氮（NO）和抗羟自由基能力（抗-OH(-)）。在光学显微镜下用HE染色观察晶状体的组织形态学。采用免疫组织化学和实时定量RT-PCR检测晶状体中钙蛋白酶II、诱导型一氧化氮合酶（iNOS）蛋白和mRNA的表达水平。结果显示，皮下注射亚硒酸钠导致模型组出现严重的核性白内障，模型组的成功率为100%。与模型组相比，GSPE处理组晶状体混浊程度和核性白内障斑块的最大直径均显著降低。此外，我们观察到亚硒酸钠处理导致抗氧化酶（SOD、CAT、GSH-PX）活性和抗-OH(-)能力显著降低，同时MDA、NO、Ca(2+)以及iNOS、钙蛋白酶II蛋白和mRNA表达水平显著升高。给予GSPE可剂量依赖性地维持这些抗氧化酶的活性和抗-OH(-)能力，同时MDA、NO、Ca(2+)以及iNOS、钙蛋白酶II蛋白和mRNA表达水平显著降低。这些结果表明，GSPE可能通过抑制晶状体中脂质过氧化和自由基的产生以及iNOS和钙蛋白酶II的激活，显著预防亚硒酸盐诱导的白内障形成。
