三丁基锡对热带爪蟾蝌蚪甲调基因mRNA表达的影响

用三丁基锡( TBT)对热带爪蟾(Xenopus tropicalis)NF51阶段蝌蚪进行48 h和96 h暴露.结果显示,50 ng·L-1和200 ng·L-1 TBTCl暴露对胚胎的存活率没有影响.50 ng·L-1TBTCl暴露组TRβ和DI 3 mRNA在蝌蚪尾巴中的表达比对照组增加了1～2.3倍.200 ...

Effects of tributyltin on mRNA expressions of thyroid hormone response genes in Xenopus tropicalis tadpoles

Xenopus tropicalis tadpoles (NF51) were exposed to TBT for 48 and 96 h, respectively. Exposures to 50 and 200 ng·L^-1 TBTCl showed no effects on the survival rate of tadpoles. The expression of TRβ and DI3 mRNA were significantly increased in the tails by 1～2.3 fold in the groups treated with 50 ng·L^-1 TBTCl. The expression of TSHβ mRNA was increased in the tails by 2 fold after 48 h of exposure. RXRα mRNA was decreased by 0.4 fold in the brains and tails, and RXRβ mRNA was increased by 5.9 fold in the tails after 96 h of exposure. MCT8 mRNA was increased by nearly 3 fold in the tails in 50 ng·L^-1 TBT treatment group and decreased by 3 fold or so in the brains in 50 ng·L^-1 TBT treatment group after 96 h of exposure. These results suggest that TBT can result in the changes of multiple mRNA expressions and show high tissue-specific differences. These mRNA are involved in the synthesis, transportations, transformations and actions, which indicate that TBT shows thyroid hormone disrupting effects. The changes of related mRNA expressions indicate that TBT might disrupt the thyroid hormone system of tadpoles by binding with retinoid X receptor. Therefore, biomarkers are not only cost-effective and sensitive endpoints in screening the thyroid disrupting chemicals but also useful in identifying the mode of action of contaminants.