中文摘要：

目的探讨多氯联苯118（PCB118）对大鼠甲状腺功能及自身免疫反应的影响。方法Wismr大鼠40只均分为四组：A组为空白对照；B、C、D组分别给予PCB11810、100、1000μg·kg-1·d-1腹腔注射，每周5次。13周后检测血清游离三碘甲状腺原氨酸（FT3）、游离甲状腺素（FT4）、促甲状腺激素（TSH）、甲状腺球蛋白（TG）、甲状腺球蛋白抗体（TGAb）、过氧化物酶抗体（TPOAb）水平，甲状腺组织过氧化物酶（TPO）rnRNA表达水平，观察甲状腺组织病理学改变。结果甲状腺组织病理学检查显示B、C、D组均可见滤泡腔塌陷、上皮脱落、间质纤维化、小血管增生，B、C组可见问质淋巴细胞浸润。随着PCB118剂量增加，B、C、D组血清FT3、FT4、TG浓度逐渐降低；D组FT3浓度明显低于A、B组（P〈0．05）；B、C、D组血清FT4、TSH浓度明显低于A组（P〈0．05）；C、D组血清TG水平明显低于A组（P〈0．05）。与A组比较，B、C组血清TGAb、TPOAb浓度显著升高（P〈0．05）；C组TPOmRNA表达水平明显高于A组（P〈0．05）。结论PCB118可导致大鼠甲状腺组织形态和功能异常，激活甲状腺自身免疫反应。

英文摘要：

Objective To study the effects of polychlorinated biphenyl ll8（PCBll8） on thyroid function and autoimmunity in rats. Methods Fourty Wistar rats were equally assigned into 4 groups. The rats in group A were taken as blank controls. The rats in groups of B,C and D were treated with intraperitoneal injection of PCB118 10,100 and 1000 μg . kg-1 . d-1 , 5 times a week for 13 weeks. The histopathology of the thyroid was observed under light microscopy. Serum levels of free thyroxine （ FT4 ）, free triiodothyronine （ FT3 ）, thyroid-stimulating hormone （ TSH ）, thyroglobulin （TG）, thyroglobulin antibody （TGAb）, and thyroid peroxidase antibody （TPOAb） were measured by radioimmunoassay. The mRNA expression of thyroperoxidase（TPO） in thyroid tissues was quantified by RT-PCIL Results The distinct histopathological changes of the thyroids, such as collapsed follicles,mesenchyme fibrosis and vascularization were seen in groups of B, C and D. Interstitial lymphocytic infiltration was observed in groups of B and C as well. Along with increasing doses of PCBll8,serum levels of FT3, FT4 and TG were decreased, in which serum level of FT3 was significantly lower in group D than that in groups of A and B（P〈0. 05）. Serum levels of FT4 and TSH were lower in groups of B,C and D than those in group A（P〈0. 05）. Serum level of TG was lower in groups of C and D than that in group A（P〈0. 05）. Serum levels of TGAb and TPOAb were higher in groups of B and C than thoae in group A（P〈0. 05）. The TPO mRNA expression was higher in group C than that in group A（P〈0. 05）. Conclusion PCBll8 could cause abnormal changes of thyroid in morphological structure and function,activate the autoimmunity of the thyroid.