高碘对小鼠脑发育的影响

高碘是否和低碘一样会导致脑发育障碍，特别是母体高碘是否会对子代造成脑发育和智力损害，是一项具有重要医学和遗传学意义而尚未进行深入研究的问题。用高碘水喂小鼠复制出高碘甲状腺肿动物模型，对高碘甲状腺肿母鼠生下的１、７、１４、２１和３０日龄仔鼠的脑重量、脑蛋白质和核酸含量进行了测定，并对３０日龄仔鼠的脑形态变化和学习、记忆能力进行了观察。结果表明，与适碘组相比，高碘组小鼠脑重量、蛋白质含量和蛋白质／ＤＮＡ比值、ＲＮＡ含量和ＲＮＡ／ＤＮＡ比值均明显降低，而ＤＮＡ含量升高。３０日龄仔鼠学习、记忆能力下降，并观察到，这些参数的变化多数从７～１４日龄开始。这提示，摄入过量碘同碘缺乏一样，不仅可引起高碘性甲状腺肿，也可对神经系统造成损害，使脑发育落后，脑功能障碍。

Effects of High Dose Iodine on Brain Development in Mice

It is an important topic in medicine and genetics, which has not yet been studied in depth, that whether high dose iodine, especially iodine excess in mother's body, can cause impediment of brain development in babies as iodine deficiency do. An animal model of goiter was reconstructed in mice with feeding them water containing high level of iodine for three months. Weight of brain, protein and nucleic acid concentrations were measured in one ,seven ,14 ,21 and 30 day old young mice, and morphological changes in the brain and their abilities of learning and memory were observed in 30 day old young mice, born to mothers with high iodine goiter. Results indicated that weight of brain, protein content, ratio of protein to DNA, RNA content, and ratio of RNA to DNA all decreased significantly, and DNA content increased in the brain of high iodine mice, as compared with those in normal iodine mice. Abilities of learning and memory in 30 day old mice decreased. And, those changes began from the seventh to 14th days after their birth. It suggests that excessive intake of iodine, as iodine deficiency, can not only cause high iodine goiter, but also damage nervous system leading to retardation of brain development and impediment of its function.