母鼠边缘性碘缺乏影响其仔鼠脑发育相关蛋白的表达

Maternal rat with marginal iodine deficiency affects the expression of brain development related proteins of its offspring

目的探讨边缘性碘缺乏对后代神经智力发育的影响及其机制。方法根据流行病学特点及文献报道的大鼠碘代谢特点建立边缘性碘缺乏大鼠模型。边缘性碘缺乏大鼠每日给予3μg碘，正常对照鼠每日给予4μg碘，低碘鼠每日给予1．2μg碘。用Western印迹方法检测仔鼠7d龄时海马脑源性神经营养因子（BDNF）及早期生长反应因子1（EGRl）的蛋白水平，用免疫组化方法检测仔鼠40d龄时海马CAl区的c-jun、c-fos蛋白表达，用水迷宫方法评估仔鼠学习及空间记忆能力。结果边缘性碘缺乏组大鼠妊娠期间fT4水平下降约30％。边缘性碘缺乏组仔鼠7d龄时海马BDNF及EGRl的蛋白水平比正常对照组明显下降（均P〈O．05），边缘性碘缺乏组仔鼠40d龄时海马CAl区的c-jun、c-fos蛋白表达也明显下降（均P〈O．05），仔鼠的空间学习记忆能力有下降趋势。结论大鼠妊娠前边缘性碘缺乏时，妊娠后FT。水平下降，影响仔鼠脑内相关蛋白的表达，对智力产生一定影响。

Objective To investigate the effects of maternal rat with marginal iodine deficiency on the nerve and intelligence development in its offspring and the related mechanisms. Methods The rat model of marginal iodine deficiency was established on the basis of epidemiological characteristics and iodine metabolism characteristics of rats reported in literatures. Marginal iodine deficiency rats were given 3μg iodine a day ; normal control rats were given 4μg iodine daily ; iodine deficiency rats were given 1.2μg iodine daily, respectively. Western blot was used to detect the protein levels of brain derived neurophic factor （BDNF） and early growth response factor 1 （ EGR1 ） in the hippocampus of 7 days newborn rats. Immunohistochemistry was used to measure c-jun and c-fos expressions in the hippocampal CA1 region of 40 days rats. Water maze method was used to measure the ability of learning and spatial memory. Results FT4 level in rats of marginal iodine deficiency group during pregnancy decreased by about 30%. Seven days after birth, the contents of EGRI and BDNF proteins in the hippocampus of the offspring from marginal iodine deficiency group were significantly decreased compared with normal control group （both P 〈 0.05 ）. Forty-day-old newborn rats in marginal iodine deficiency group also showed significantly decreased c-jun and c-fos expressions in the hippocampal CAI region（ both P〈0.05 ）, along with a decreased trend of spatial learning and memory ability. Conclusions FT4 level will significantly decrease after pregnancy if rats have marginal iodine deficiency, affecting the expression of related proteins in the brain of newborn rats and having a negative impact on offspring brain development.