目的：探讨大鼠硒性白内障形成是否与血-视网膜屏障的发育情况有关。

方法：测定了不同年龄段大鼠晶状体中谷胱甘肽过氧化物酶(GPx)活性、丙二醛(MDA)水平以及眼球中的硒含量； 并采用氢氧化镧[La(OH)₃]示踪法观察不同年龄段血-视网膜屏障的发育情况。

结果：开眼前幼鼠GPx的酶活性最高，之后随着年龄的增长而逐渐下降； 出生第20d大鼠视网膜色素上皮层的La(OH)₃分布显著少于出生第11天龄幼鼠。对出生第9d大鼠注射亚硒酸钠(Na₂SeO₃)48h后，La(OH)₃大量进入视网膜的内层，视网膜色素上皮层受到严重破坏； 而注射相同剂量Na₂SeO₃的18天龄大鼠在48h后，只有少量的La(OH)₃进入。开眼前大鼠晶状体中MDA含量最高，开眼后下降显著； Se组是对照组的5倍。再者，大鼠眼中的La(OH)₃分布与眼球中的硒含量、晶状体中的MDA水平的变化基本一致。

结论：亚硒酸钠诱导形成的硒性白内障主要原因是幼鼠血-视网膜屏障发育不成熟，而不是抗氧化能力。

METHODS: Activity of GPx, MDA level in lens and selenium content in the eyeballs of different ages rats were determined. Besides, lanthanum hydroxide \〖La(OH)₃\〗 tracer method was used to detect development status of blood-retina barrier at different ages.

RESULTS: The result showed that the enzyme activity of GPx was highest in young rats before open eyes, but then decreased gradually with age. Distribution of La(OH)₃ in retinal pigment epithelial layer of 20-day-old rats was significantly less than 11-day-old rats. Injecting sodium selenite to 9-day-old rats, lanthanum hydroxide increased obviously and extended to the inner layers of the retina after 48h, and the retinal pigment epithelial layer was damaged seriously; while injecting sodium selenite to 18-day-old rats with the same dose, number of lanthanum hydroxide decreased significantly and did not extend to the inner layer after 48h.Before opening eyes, the content of MDA in the lens of rats was the highest, and decreased significantly after opening eyes. The Se group was 5 times as that of the control group. Besides, in these groups of rats, selenium content in the eyeballs and MDA level in the lens were in agreement with the change of La(OH)₃ distribution.

CONCLUSION: These results indicated that antioxidant capacity in the eyelid unopened rats is not the main reason for selenite induced cataract formation. The real reason is that blood-retina barrier development is not mature in the eyelid unopened rats.