Department of Ophthalmology, Eye Ear Nose and Throat Hospital of Fudan University, Shanghai, PR China.
Ophthalmic Res. 2012;47(2):87-97. doi: 10.1159/000330504. Epub 2011 Aug 25.
To determine whether a diet containing excessive amounts of milk aggravates naphthalene-initiated cataracts in a common animal model of age-related human cataract.
Ninety Sprague-Dawley rats were fed a natural diet supplemented with either water (group A), normal amounts of milk (group B), excessive amounts of milk (group C), naphthalene plus water (group D), naphthalene plus normal amounts of milk (group E), naphthalene plus excessive amounts of milk (group F). Cataract development was monitored weekly using a slit lamp and lens gray value analysis. Concentrations of reactive oxygen species (ROS), reduced glutathione (GSH) and malondialdehyde (MDA) in rat lenses were measured to determine the role of oxidative stress in cataract induction.
By week 4, the cortical gray value was significantly higher in group F than that in group D, and the cortical gray value was significantly higher in group D than in group A. However, by week 8, no significant differences were observed among groups C, F, B, E and A. ROS concentrations in lenses of rats of groups C and F were slightly higher than in those of groups B, E and A, but ROS concentrations in group F were significantly higher than in the other groups receiving naphthalene (i.e. groups D and E). GSH concentrations in group F were significantly lower than in the other groups. MDA concentrations in group F were significantly higher than in the other groups receiving naphthalene, indicating increased lipid peroxidation induced by naphthalene plus excessive intake of milk.
Our results provide quantitative evidence that excessive intake of milk aggravates naphthalene-initiated cataracts, which is probably due to oxidative damage caused by increased ROS.
在萘诱导的与人年龄相关的白内障的常见动物模型中，确定摄入过量牛奶的饮食是否会加重白内障的形成。
90 只 Sprague-Dawley 大鼠分别喂食天然饮食，其中一组（A 组）饮用普通水，一组（B 组）饮用正常量的牛奶，一组（C 组）饮用过量的牛奶，一组（D 组）用萘和水喂养，一组（E 组）用萘和正常量的牛奶喂养，一组（F 组）用萘和过量的牛奶喂养。每周使用裂隙灯和晶状体灰度值分析监测白内障的发展情况。测量大鼠晶状体中活性氧（ROS）、还原型谷胱甘肽（GSH）和丙二醛（MDA）的浓度，以确定氧化应激在白内障诱导中的作用。
第 4 周时，F 组皮质灰度值明显高于 D 组，D 组皮质灰度值明显高于 A 组。然而，第 8 周时，C、F、B、E 和 A 组之间无显著差异。C 组和 F 组大鼠晶状体中的 ROS 浓度略高于 B、E 和 A 组，但 F 组的 ROS 浓度明显高于接受萘的其他两组（即 D 组和 E 组）。F 组的 GSH 浓度明显低于其他组。F 组的 MDA 浓度明显高于接受萘的其他组，表明萘和过量摄入牛奶引起的脂质过氧化增加。
我们的结果提供了定量证据，表明过量摄入牛奶会加重萘诱导的白内障，这可能是由于 ROS 增加引起的氧化损伤所致。
