农药叶枯宁对大鼠血清甲状腺素水平影响的时效关系

目的 ]研究甲状腺素干扰物叶枯宁对大鼠血清游离T4(FT4)和促甲状腺激素 (TSH)水平的影响及其时效关系 ,为建立甲状腺素干扰物甄别方法体系的体内方法提供实验依据。 方法 ]叶枯宁二甲亚砜溶液灌胃染毒 ,剂量为 5 0mg/kg ,分别设 5、6、10、2 0d实验组及溶剂对照组 ,在染毒期满后处死动物 ,取血清测FT4和TSH ,同时观察甲状腺组织学改变。 结果 ]与对照相比 ,5d组出现显著的FT4降低并伴TSH升高 (P <0 0 5 ) ,6d及以后组则未见差异 ;组织学观察到 5d、6d组甲状腺滤泡上皮增生 ,10d组出现实心芽 ,2 0d组出现实心继发滤泡。 结论 ]叶枯宁对大鼠血清FT4和TSH水平的影响发生在 5d之内 ,并可继发引起甲状腺增生。本实验为建立甲状腺素干扰物的初筛方法奠定了基础

The Time-effect Relationship Between Pesticide YE KU NING and Thyroid Hormone Levels in Rats

Objective] To study the effect of pesticide YE KU NING on the levels of serum FT4 and TSH in rats,and their time effect relationship. Methods] YE KU NING dimethylsulfoxide solution was administered to rats by gavage at a dose of 50 mg/kg body weight for 5,6,10,20 days,respectively. The rats in the control group were given solvent dimethylsulfoxide by oral gavage at the same volume. All animals were sacrificed after the last dosage and the levels of FT4 and TSH in serum were measured by radioimmunoassay. The histological changes of thyroid gland were observed too. Results] A significant decrease in FT4 level but significant increase in TSH level ( P <0 05) was found in rats given YE KU NING for 5 days as compared with the control rats. Histological observation of thyroid gland showed proliferation of follicular epithelium on 5 th and 6 th day of experiment group,formation of solid bud on 10 th day,and formation of sequential follicles in the solid bud on 20 th day. Conclusion] The effect of YE KU NING on the level of serum FT4 and TSH in rats occurs within 5 days and may be followed by the consequent hyperplasia of thyroid gland. This in vivo experiment provides a foundation for screening methods for thyroid hormone disruptors.