碘过量对后代鼠脑NSE和GFAP表达的影响

Influence of Iodine Excess on Expression of NSE and GFAP in Brains in Generation of Rats

目的观察碘过量对后代鼠神经元特异性烯醇化酶和胶质纤维酸性蛋白表达的影响。方法将断乳后一个月Wistar大鼠随机分为五组(NI、5HI、10HI、50HI和100HI),饮用不同浓度的碘水,饲养3个月后雌雄合笼,取第二代60日龄鼠,测量血清甲状腺激素值,以NSE和GFAP为观察指标,研究后代鼠大脑的发育情况。结果各碘过量组甲状腺激素水平呈下降趋势,100HI组呈明显甲低状态;NSE的免疫组化和形态计量学显示:海马CA3区NSE阳性细胞的NA、VV和灰度值随碘过量的严重程度而呈下降趋势,在100HI组呈明显的统计学差异。各组GFAP阳性星形胶质细胞阳性显色强弱未见明显不同。结论大鼠对碘摄入量的增高,只有在100HI组可以观察到以NSE表达降低为主要特点的脑发育障碍,其发病机理可能与碘过量所致的甲状腺功能低下有关。

Objective To observe the effects of iodine excess on expressions of neuron specific enolase（NSE） and glial fibrillary acidic protein（GFAP） in filial generation of rats. Methods The Wistar rats were divided into five groups by randomized design. The rats were drinking water at different iodine levels （NI, 5HI, 10HI, 50HI and100HI）. Mter being fed three months, the rata were mated and their filial generations at the age of 60 day observed. The serum thyroid hormones at the age of 60 day were measured. Immunohistochemical method combining with image analysis techniques were used to demonstrated expressions of NSE and GFAP in hippecampus of beth control and iodine excess rats. Results The results of serum thyroid hormones revealed the decreasing tendency in experimental groups by gradually increasing iodine intake, however, hypothyroidism were obviously in 100HI group. Immunohistochemical staining and morphological images analysis of NSE positive neurons in hippocampus CA3 area indicated that numerical density on area （ NA ）, volume density （ Vv ） and the average of grey scale were gradually decreased coincidenced with iodine excess levels, furthermore, statistically significance in 100HI group. GFAP positive astrocytes in hippocampus CA3 area showed that the changes of the astrocytes were insignificant. Conclusions NSE expressions were decreased obviously in 100HI group at the age of 60 day. Iodine excess can cause brain under development in their filial generation, and the pathogenesis maybe related to hypothyroidism induced by iodine excess.