全氟辛磺酸对于爪蟾的甲状腺激素干扰效应

运用两栖类变态实验(AMA)研究了全氟辛磺酸(PFOS)对于非洲爪蟾(Xenopus laevis)蝌蚪的生长、变态和甲状腺组织结构的影响.结果显示,与对照组相比,7d后,10,50和250μg.L-1PFOS暴露组蝌蚪的后肢长分别减小了17%,11%和18%,蝌蚪的发育延缓了1~2个阶段;19d后,10,50和250μg.L-1PFOS组蝌蚪的体重分别增加了17%,10%和20%,体长分别增加了5%,4%和6%,而10μg.L-1和250μg.L-1PFOS组蝌蚪的后肢长分别减小了12%和13%;暴露组甲状腺组织结构出现滤泡数目减少、上皮细胞增生、胶质减少甚至滤泡溶通等现象.结论是,在本实验浓度下,PFOS对于非洲爪蟾的蝌蚪生长有促进作用,对于变态发育过程却有抑制作用.参照AMA的方法,可以判断PFOS为抗甲状腺激素干扰物.

Thyroid disrupting effects of perfluorooctane sulfonate on Xenopus laevis

The amphibian metamorphosis assay (AMA) was used to detect thyroid disrupting effects of perfluorooctane sulfonate (PFOS). Xenopus laevis tadpoles at stage 51 were exposed to 10, 50 and 250 μg·L-1 PFOS. The growth, metamorphosis and thyroid histology were observed. After 7 days of exposure, the hind limb lengths were decreased by 11%～18%, and 1 or 2 developmental stages were delayed in treatment groups compared with the control. After 19 days of exposure, the body weights were increased by 10%～20%, the body lengths were increased by 4%～6%, and the hind limb lengths were decreased by 12%～13% in treatment groups. PFOS decreased the number of thyroid follicles, in which cell hyperplasia, colloid depletion and vacuolation were observed. These results suggested that PFOS inhibited the development and increased the growth of X laevis. According to AMA, our results indicated that PFOS was an anti thyroid hormone disrupting chemical.