碘过量致甲减大鼠血中微量元素的变化

Changes of trace elements in blood of rats with hypothyroid caused by iodine excess

目的观察微量元素变化与碘过量所导致的大鼠甲状腺功能变化之间的关系。方法健康SPF/VAF级初断乳SD大鼠50只,雌雄各半,随机分为适碘组(NI)、5倍(5HI)、10倍(10HI)、50倍(50HI)、100倍碘过量组(100HI),每组各10只。通过饮用不同KIO3含量的去离子水,使五组碘摄入量分别约为6.0、30.0、60.0、300.0、600.0μg/d,干预6个月使各组大鼠碘营养水平达到实验预期。测定尿碘浓度,甲状腺重量,血清甲状腺激素,测量血清中镁(Mg)、钙(Ca)、铬(Cr)、锰(Mn)、铜(Cu)、锌(Zn)和硒(Se)的含量。结果大鼠碘营养各项指标均符合试验设计要求。与对照组相比,5、10、50倍组甲状腺功能无明显变化,100倍组f T3和fT3/fT4明显降低。与NI组大鼠血清中微量元素相比较,碘过量大鼠Cr,Mn,Zn增加(P<0.05),其他元素变化无统计学意义。结论多种微量元素的变化可能在碘对甲状腺的功能影响中产生重要作用。

Objective To understand the relationship between the changes of microelements and thyroid dysfunction caused by iodine excess in rats.Methods Fifty healthy SPF/VAF primary weaning SD rats(half male and half female)were randomly divided into five groups according to the body weight:NI,5HI,10HI,50HI and 100 HI,and iodine intake doses were 6.0,30.0,60.0,300.0 and 600.0μg/d respectively by drinking deionized water with different concentrations of potassium iodate.The iodine nutrition level of rats in each group was up to the expectation of the experiment by iodine intake control for six months.Urinary iodine concentration,thyroid weight,serum thyroid hormone and the contents of Mg,Ca,Cr,Mn,Cu,Zn and Se in serum were measured.Results All indexes of iodine nutrition of rats were in accordance with the requirements of experimental design.Compared with the NI group,there was no significant change of thyroid function in the 5HI,10HI,and 50HI group,but fT3 and fT3/fT4 were reduced in the 100 HI group.Compared with the trace elements in serum of the NI group,Cr,Mn,and Zn in the 100 HI group increased(P<0.01 or 0.05).There was no significant change in other elements.Conclusion The changes of various microelements may have synergistic effects on the function of thyroid induced by iodine.