十溴联苯醚（BDE-209）对成年大鼠甲状腺激素的影响

多溴联苯醚(PBDEs)是现代工业中广泛应用的溴系阻燃剂,PBDEs具有持久性有机卤素污染物(Organohalogen Contaminants,OHCs)和内分泌干扰物(Endocrine Disrupters,EDs)的化学物理特性.PBDEs的生物毒性也是国际上环境生态科学的关注热点.论文建立了十溴联苯醚(BDE-209)暴露剂量的成年大鼠模型,测定了不同暴露剂量的实验动物血清甲状腺激素(Thyroid hormones,THs)水平,初步研究了PBDEs污染物对生物体甲状腺激素的影响.BDE-209的量-效关系研究结果显示,TT4、FT4和TT3浓度均随着暴露剂量的提高而下降,这可能是BDE-209对甲状腺合成分泌T4、T3起到了抑制作用.不同BDE-209暴露剂量下,TT4~FT4以及TT4~TT3的正相关系数大于FT3~TT3以及FT3~FT4,这意味着BDE-209暴露对于T4从甲状腺激素转运结合蛋白(Transthyretin,TTR)的分离与脱碘过程影响不明显,而影响了结合态T3从TTR的分离过程以及FT4的脱碘过程,从而对甲状腺激素的平衡具有干扰效应.采用基准点分析法,研究了BDE-209对于甲状腺干扰相对效应的时间-效应关系,实验表明由于甲状腺的应激作用,对于毒物具有自我防御功能,BDE-209对甲状腺的干扰效应在5~8d后才有所显现,持续时间至少为14d.

Disturbance of Decabrominated Diphenyl Ether(BDE-209)to Thyroid Hormones of Adult Rats in Vivo

Polybrominated diphenyl ethers (PBDEs)are brominated flame retardants used in modern industry. PBDEs share close physicochemical properties with other persistent organohalogen contaminants (OHCs) and endocrine disrupters(EDs). The biotoxicity of PBDEs has been paid close attention by world environmental ecologists. In this paper, serum thyroid hormones (THs) level of the adult rats exposed to decabrominated diphenyl ether (BDE -209) at different doses was determined and the influence of BDE -209 to thyroid hormones (THs) was studied preliminarily. The dose dependent relationships between THs and BDE -209 concentrations were studied. The results indicated that TT4, FT4 and TT3 concentrations were significantly decreased with the increase of BDE-209 exposure doses in the treatment groups. It seemed that THs (T4, T3)synthesis and release of thyroid body were inhibited by BDE-209. The positive correlation coefficients of TT4~FT4 and TT4~TT3 at different BDE-209 exposure doses were higher than those of FT3~TT3 and FT3~FT4. It implied that exposure of BDE -209 would not affect obviously the separation from transthyrein (TTR)and deiodination of binding T4, while would affect the separation of binding T3 from TTR and deiodination of free FT4, consequently the balance of thyroid system was disturbed by BDE-209. The time dependent relationships between BDE -209 disturbance relative effects to thyroid body and days were studied using benchmark analysis. The results indicated that the disturbance effects of BDE - 209 in thyroid system would appear after 5 to 8 days and last at least 14 days due to the strain of thyroid and antipoison defense system of living body.