中文摘要：

为探讨低浓度多氯联苯（polychlorinated biphenyls,PCBs）商业混合物Aroclor1254对大鼠甲状腺结构及功能的影响,本文将12只雄性Wistar大鼠随机分为对照组和PCBs暴露组（Aroclor1254组）,对照组腹腔注射Aroclor1254的溶剂玉米油,暴露组以2000μg·kg-^1·d^-1的剂量行腹腔注射Aroclor1254,每周注射5d,连续注射13周.采用HE染色、免疫组化及电镜技术观察PCBs对大鼠甲状腺组织结构的影响,酶联免疫吸附试验（ELISA）检测血清TSH、Free-T3、Free-T4水平,逆转录聚合酶链反应（RT-PCR）检测甲状腺球蛋白（Tg）及钠碘转运体（NIS）mRNA表达水平.研究结果发现,与对照组比较,暴露组大鼠甲状腺组织内单核巨噬细胞（ED-1＋细胞）浸润增多,甲状腺微观结构受损,血清TSH水平显著升高,甲状腺组织TgmRNA及NISmRNA表达显著下调.研究结果表明,低浓度PCBs长期暴露可导致大鼠甲状腺结构破坏及功能损伤.

英文摘要：

This study was to investigate the toxic effects of Aroclor1254 exposure on the structure and functions of thyroid in animal models of rats. Two groups of wistar rat （ n = 6 each） received intraperitoneal injection of Aroclor1254 at a dose of 2000μg·kg-^1·d^-1 or corn oil as the corresponding control, respectively, 5 times a week for 13 weeks. After sacrificed, the histology of thyroids were observed by electron microscopy and HE stain. Thyroid stimulation hormone （TSH）, serum free triiodothyroinine （FT3） and free thyronine（FT4） were measured using ELISA method, mRNA expression of thyroglobulin and sodium iodine symporter was tested by RT-PCR. The results showed that Aroclor1254 could significantly change the histopathology of thyroid, with increased infiltrated mononuclear macrophages （ED-1 ＋ cell）. Compared with control group, serum TStt greatly increased while thyroid Tg and NIS mRNA expression reduced significantly in Aroclor1254 group. Our investigation showed that long - term exposure to low - dose Aroclor1254 might impair the structure and function of thyroid in rats.