过氯酸铵对大鼠甲状腺的毒作用

Toxic effects of ammonium perchlorate on thyroid of rats

目的 研究过氯酸铵 (AP)对甲状腺的毒作用影响。方法 用Wistar大鼠 88只 ,随机分为 4组 ,分别经口染毒 13周和 36周。染毒 13周 ,3个组AP剂量分别为 12 9、2 5 7、5 14mg·kg-1·d-1,1个对照组则饮水 ;染毒 36周 ,3个组AP剂量分别为 1.2、4 6 .5、4 6 5 .0mg·kg-1·d-1,1个对照组则饮水。观察大鼠活动表现及体重变化 ,检测血清中甲状腺激素水平及观察其病理改变。结果 不同时间AP染毒后大鼠活动未见异常 ,体重增长亦无明显差异。染毒 13周 ,5 14mg组游离三碘甲状腺原氨酸(FT3 2 .4 8pmol/L)、游离甲状腺素 (FT413.33pmol/L)均低于对照组 (3.2 4、2 0 .92pmol/L) ,促甲状腺激素 (TSH 0 .38mIU/L)、甲状腺球蛋白 (TG 3.37μg/L)均高于对照组 (0 .2 9mIU/L、2 .0 0μg/L) ,差异均有显著性 (P <0 .0 5 ) ;其他组各指标差异均无显著性 (P >0 .0 5 ) ;染毒 36周 ,4 6 5mg组FT3 (2 .6 5pmol/L)明显低于对照组 (4.97pmol/L) ,差异有显著性 (P <0 .0 1) ;4 6 .5、4 6 5mg组FT4(10 .6 3、2 .17pmol/L)明显低于对照组 (15 .74pmol/L) ,差异有显著性 (P <0 .0 5 ,P <0 .0 1) ;4 6 5mg组TSH(0 .34mIU/L)与对照组 (0 .14mIU/L)比较 ,差异有显著性 (P <0 .0 5 ) ;1.2mg组各指标均未见明显损害变化。镜检 1.2mg组甲?

Objective To study the effects of toxicity of ammonium perchlorate(AP) on thyroid of rats. Methods Eighty-eight Wistar rats were treated orally with different dosages of AP.Three treated groups received 129,257,514 mg·kg -1 ·d -1 of AP respectively and one control group drunk water for 13 weeks.Another 3 groups received 1.2,46.5,465.0 mg·kg -1 ·d -1 of AP respectively and one control group drunk water for 36 weeks.The behavior and change of body weight in rats were observed.The levels of thyroid hormones in serum were measured and the pathological changes of thyroid tissue were observed as well. Results There were no differences in behavior and change of body weight between different AP exposure time.When the rats were treated with AP 514 mg for 13 weeks,free triiodothyronine(FT_3,2.48 pmol/L),free thyroxin(FT_4,13.33 pmol/L) were lower than those in control group(3.24,20.92 pmol/L respectively, P <0.05).Thyroid-stimulating hormone(TSH,0.375 mIU/L),thyroglobulin(TG,3.37 μg/L) were higher than those in control group(0.29 mIU/L,2.00 μg/L respectively, P <0.05).When the rats were treated with AP 465 mg for 36 weeks,FT_3(2.65 pmol/L) was lower than that in control group(4.97 pmol/L, P <0.01).FT_4 in 46.5,465 mg groups(10.63,2.17 pmol/L respectively) were lower than that in control group(15.74 pmol/L, P <0.05, P <0.01).TSH in 465 mg group(0.34 mIU/L) was higher than that in control group(0.14 mIU/L, P <0.05).Histopathologic examination showed that follicle proliferation,no colloid in follicle,gore,follicular diminishing or atresia were found in 46.5,465 mg groups with a dose-effect relationship. Conclusions The toxic effects of Ap on the growth of rats were not found,but those on the thyroid of rats were found significantly.Thyroid is the target organ of AP.It is considered that none effect dose of AP for rat thyroid may be 1.2 mg·kg -1 ·d -1 ,its threshold dose may be 46.5 mg·kg -1 ·d -1 .