高碘引起大鼠海马神经细胞凋亡的实验研究

The Experimental Study of the Apoptosis in Rat Hippocampus Induced by High Iodine

目的观察长期高碘对大鼠海马神经细胞形态结构及细胞凋亡的影响。方法断乳1月龄的SD大鼠随机分为三组,对照组、高碘Ⅰ组、高碘Ⅱ组,分别以含碘量为5μg/L、5000μg/L、10000μg/L的自来水及普通饲料喂养6个月,定量测定血清甲状腺激素(TT3、TT4)水平;光镜、电镜下观察海马神经元形态结构及超微结构的改变;应用流式细胞仪检测细胞凋亡率及细胞周期的变化。结果对照组、高碘Ⅰ组、高碘Ⅱ组血清TT3、TT4呈逐渐下降趋势,但各组间差异无统计学意义(P>0.05)。与对照组比较高碘组海马神经元尼氏体减少,体积变小。超微结构观察:海马神经细胞核内染色质浓缩成块,聚集在核膜边缘,形成花瓣状、马蹄状等不规则形态,核膜内陷、包裹聚集的染色质形成凋亡小体;流式细胞仪检测高碘组引起海马细胞周期改变,细胞凋亡率也明显高于对照组(P<0.01),但两个高碘组间无统计学意义(P>0.05)。结论长期高碘可引起海马神经元损伤及凋亡,细胞周期改变,凋亡率增加。

Objective To investigate the morphological structure and the apoptosis in rat hippocampus induced by high iodine. Methods An animal model of goiter was reconstructed in rat with feeding them water containing different level of iodine for 6 months. Rats were randomly divided into three groups： control group, high iodine group Ⅰ and high iodine group Ⅱ,Hippocampus morphological changes and ultra structure were observed. Using radio -immunoassay, the serum thyroid hormone were measured. The effect of excess iodine on apoptosis and cell cycle in hippocampus was detected by using flow cytometry. Results The levels of serum thyroid hormones was decreased gradually from control group to high iodine group Ⅱ, but there were no remarkable differences among three groups （ P 〉 0. 05 ） . The morphologic damage was found in the dentate gyrus of hippocampus, and the incidence of apoptosis increased in hippocampus of high iodine group than that in control group （ P 〈 0. 05）, but there was no different between high iodine group （P 〉 0. 05） . Conclusions High iodine may cause definite histological changes and the excess apoptosis in hippocampus.