连翘提取物对实验性自身免疫性甲状腺炎大鼠甲状腺损伤的影响

Effects of forsythia suspensa extract on thyroid injury in rats with experimental autoimmune thyroiditis

目的:探讨连翘提取物(FSE)对实验性自身免疫性甲状腺炎(EAT)的影响及其可能的作用机制。方法:将90只SD大鼠分为对照组、模型组、FSE 25 mg/kg组、FSE 50 mg/kg组、FSE 100 mg/kg组和硒酵母片组(Selenious组,300μg/kg),除对照组外,其余各组大鼠均采取皮下注射含猪甲状腺球蛋白的不完全弗氏佐剂制备EAT模型,末次注射完成后FSE25 mg/kg组、FSE 50 mg/kg组、FSE 100 mg/kg组分别给予25、50、100 mg/kg FSE灌胃,Selenious组灌胃300μg/kg硒酵母片,模型组和对照组灌胃等体积生理盐水,连续灌胃2周。HE染色观察甲状腺病理学变化,放射免疫法测定甲状腺功能血清学指标,qRT-PCR检测甲状腺组织炎症相关因子的mRNA水平,ELISA检测血清氧化应激指标,Western blot检测NLRP3/Caspase-1通路蛋白表达情况。结果:对照组甲状腺泡呈椭圆形或圆形,甲状腺组织无淋巴浸润现象,模型组甲状腺泡萎缩、损伤,且伴有上皮增生和间质淋巴浸润现象,FSE(50、100 mg/kg)组、Selenious组甲状腺泡损伤、生皮质增生和炎症细胞浸润改善明显。模型组血清TgAb、TPOAb、TSH、T3、T4、蛋白质羰基、8-OHdG和MDA水平均明显高于对照组(P<0.05),甲状腺组织IL-17、IFN-γmRNA水平和NLRP3、ASC、cleaved-Caspase-1/Pro-Caspase-1及cleaved-IL-1β/Pro-IL-1β蛋白表达均高于对照组(P<0.05),而甲状腺组织中IL-4和IL-10 mRNA水平均低于对照组(P<0.05)。FSE 50 mg/kg组、FSE 100 mg/kg组和Selenious组血清TgAb、TPOAb、TSH、T3、T4、蛋白质羰基、8-OHdG及MDA水平均明显低于模型组(P<0.05),甲状腺组织中IL-17、IFN-γmRNA水平和NLRP3、ASC、cleavedCaspase-1/Pro-Caspase-1及cleaved-IL-1β/Pro-IL-1β蛋白表达均低于模型组(P<0.05),而甲状腺组织中IL-4和IL-10 mRNA水平均高于模型组(P<0.05)。结论:FSE可改善EAT大鼠甲状腺损伤,可能与调节NLRP3炎症小体和免疫失调有关。

Objective:To explore the effects of forsythia suspensa extract(FSE)on experimental autoimmune thyroiditis(EAT)and its possible mechanism of action.Methods:A total of 90 SD rats were divided into control group,model group,FSE 25 mg/kg group,FSE 50 mg/kg group,FSE 100 mg/kg group and selenium yeast tablet group(Selenious group,300μg/kg).Except for control group,rats in other groups were injected subcutaneously with incomplete Freund's adjuvant containing porcine thyroglobulin to prepare EAT models.After the last injection,FSE 25 mg/kg group,FSE 50 mg/kg group and FSE 100 mg/kg group were given intragastric administration of 25,50 and 100 mg/kg FSE,Selenious group was given intragastric administration of 300μg/kg selenious,model group and control group were given intragastric administration of the same volume of normal saline for 2 weeks.Pathological changes of thyroid were observed by HE staining,serological indexes of thyroid function were detected by radioimmunoassay,mRNA levels of inflammation-related factors in thyroid tissues were detected by qRT-PCR,serum oxidative stress indexes were detected by ELISA,expressions of NLRP3/Caspase-1 pathway proteins were detected by Western blot.Results:In control group,thyroid vesicles were oval or round,and there was no lymphatic infiltration in thyroid tissues.In model group,thyroid vesicles were atrophied and damaged,which were accompanied with epithelial hyperplasia and interstitial lymphatic infiltration.In FSE(50,100 mg/kg)groups and Selenious group,damage of thyroid vesicles,epithelial hyperplasia and inflammatory cells infiltration were significantly improved.Levels of serum TgAb,TPOAb,TSH,T3,T4,protein carbonyl,8-OHdG and MDA in model group were significantly higher than those in control group(P<0.05),levels of IL-17 and IFN-γmRNA in thyroid tissues,expressions of NLRP3,ASC,cleaved-Caspase-1/Pro-Caspase-1 and cleaved-IL-1β/Pro-IL-1βwere higher than those in control group(P<0.05),while levels of IL-4 and IL-10 mRNA in thyroid tissues were lower than those in control group(P<0.05).Levels of serum TgAb,TPOAb,TSH,T3,T4,protein carbonyl,8-OHdG and MDA in FSE 50 mg/kg group,FSE 100 mg/kg group and Selenious group were significantly lower than those in model group(P<0.05),levels of IL-17 and IFN-γmRNA in thyroid tissues,expressions of NLRP3,ASC,cleaved-Caspase-1/Pro-Caspase-1 and cleaved-IL-1β/Pro-IL-1βwere lower than those in model group(P<0.05),while levels of IL-4 and IL-10 mRNA in thyroid tissues were higher than those in model group(P<0.05).Conclusion:FSE can improve thyroid damage in EAT rats,which may be related to regulating NLRP3 inflammasome and immune disorders.