高碘摄入对SD大鼠钠/碘同向转运体蛋白表达影响的免疫组化研究

Effects of excessive iodine intake on the expression of sodium/iodine symporter in SD rats

目的:动态观察长期高碘摄入对SD大鼠甲状腺细胞钠/碘同向转运体(NIS)蛋白表达的影响。方法:SD大鼠分别饲以去离子水及不同碘浓度的碘化钾水,给碘后1 d及1,2,4,8周处死。测定尿碘、组织碘含量,免疫组织化学方法观察甲状腺细胞NIS蛋白表达水平。结果:高碘摄入可引起甲状腺滤泡细胞膜表面NIS蛋白表达的下降。短期较低浓度的高碘摄入对NIS蛋白的表达无明显影响,而较高浓度的碘摄入则引起NIS蛋白表达的明显减少;长期高碘摄入对NIS蛋白表达的抑制作用,可在机体自我调节机制作用下得以部分恢复,但NIS蛋白表达仍处较低水平。结论:高碘摄入可导致甲状腺细胞表面NIS蛋白表达下降,随摄碘浓度的增加抑制作用增强;不同浓度的碘摄入对NIS蛋白表达的抑制作用表达时间不同。

Objective： To study the effects of excessive iodine intake on the expression of sodium/iodine symporter （NIS） protein in SD rats. Methods： SD rats were fed with distilled water and iodized distilled water, separately. Urinary iodine and tissue iodine were measured. The expressions of NIS protein were determined by immunohistochemical method in different periods of iodine treatments. Results： The expression of NIS protein was inhibited by excessive iodine intake, and the greater the iodine uptake, the Iower the level of NIS protein expression. The short-term effects of excessive iodine intakes on the expression of NIS protein were different, Low concentration of iodine intake had no effect on NIS expression, while high concentration of iodine intake decreased the expression of NIS protein. After the rats received iodine for a long period, the inhibition of NIS by high concentration of iodine intake partly resumed by autoregulation, but NIS expression still kept at low level. Conclusion： Excessive iodine intake may decrease the expression of thyroid sodium/iodide symporter in SD rats, and the decreased levels depends on the concentrations of iodine intakes. Different concentrations of iodine intakes may lead to the difference in the inhibition of NIS expression.