褪黑素对抑制过氧化氢诱导大鼠白内障形成的实验研究

目的  探讨褪黑素（MLT）对过氧化氢诱导大鼠白内障形成的抑制作用。方法  体外取出发育正常的Wistar大鼠晶状体,按随机原则分为3组：A组为空白对照组,B组为过氧化氢（H2O2）处理组,C组为在B组的基础上加入不同浓度的MLT,使MLT终浓度分别为10（C1组）、30（C2组）、50（C3组）、100（C4组）、200（C5组）μmol/L。体外培养24h后,观察各组晶状体的混浊程度,采用Image Pro Plus（IPP）6.0软件分析晶状体下黑色条带的平均光密度值；酶标仪测定各组晶状体组织的蛋白含量、还原型谷胱甘肽（GSH）、丙二醛（MDA）、总抗氧化能力（T AOC）、超氧化物歧化酶（SOD）、过氧化氢酶（CAT）含量。结果  裂隙灯下观察可见,各组晶状体混浊程度不同,C组晶状体平均光密度值高于B组（P＜0.05）,即C组晶状体透明性高于B组。C组晶状体组织中的GSH、T AOC、SOD及CAT含量高于B组（P＜0.05）,而MDA含量低于B组（P＜0.05）。结论  褪黑素可提高氧化损伤晶状体的抗氧化能力,有效抑制体外过氧化氢诱导大鼠白内障的形成。

Experimental study on melatonin inhibiting hydrogen peroxide-induced cataract in rats

Objective  To investigate the effects of melatonin(MLT) in preventing hydrogen peroxide-induced cataract in rats. Methods  The lenses of the cultured normal Wistar rats in vitro were randomly divided into 3 groups: the control group (group A ), the group treated by hydrogen peroxide(group B), and the group treated by hydrogen peroxide and melatonin(10, 30, 50, 100 and 200μmol/L) (group C1, group C2,  group C3, group C4 and group C5). At the end of the study period (24th hour), the lenticular opacification of lenses was examined and the mean densities of black bands under the lenses were analyzed by Image-Pro Plus（IPP）6.0 software .At the same time, the levels of protein, glutathione(GSH), malondialdehyde(MDA), total antioxidiation ability(T AOC), superoxide dismutase(SOD) and catalase (CAT) were tested. Results  The lenses were observed with slit-lamp microscope after 24 hours of incubation, and there were differences in lenticular opacification between each group. The mean density of lenses in Group C was significantly higher than lenses in Group B (P<0.05). To compare with the biochemical parameters of group B, the levels of GSH, T-AOC, SOD and CAT of group C increased statistically; the level of MDA reduced statistically(P<0.05). Conclusion  Melatonin can effectively enhance antioxidant ability of the oxidative damaged lense, and also can inhibit the development of hydrogen peroxide induced cataract of rats in vitro.