基于TGF-β1/FOXP3/RORγt信号通路探讨芦荟多糖对小鼠自身免疫性甲状腺炎的保护作用

Protective effect of aloe polysaccharide on mice autoimmune thyroiditis based on TGF-β1/FOXP3/RORγt signaling pathway

目的基于TGF-β1/FOXP3/RORγt信号通路观察芦荟多糖对小鼠自身免疫性甲状腺炎的保护作用。方法选用2月龄雌性小鼠30只,随机分为正常组、模型组和芦荟多糖组,每组10只。通过皮下多点注射猪甲状腺球蛋白(PTg)+高碘水法建立小鼠自身免疫性甲状腺炎模型,其中芦荟多糖组灌胃给药300 mg/(kg·d),其余两组灌胃给予等量生理盐水。药物干预4周后分别HE染色观察各组小鼠甲状腺组织病理形态学变化;ELISA法检测各组小鼠血清游离三碘甲状腺原氨酸(free triiodothyronine,FT_(3))、游离四碘甲状腺原氨酸(free thyroxine,FT_(4))、促甲状腺激素(thyroid-stimulating hormone,TSH)、甲状腺球蛋白抗体(thyroglobulin antibody,TGAb)、甲状腺过氧化物酶抗体(thyroid peroxidase antibody,TPOAb)、肿瘤坏死因子α(tumor necrosis factorα,TNF-α)、白介素1β(interleukin 1β,IL-1β)、白介素10(interleukin 10,IL-10)、白介素17(interleukin 17,IL-17)和甲状腺信号转导与转录激活因子3(signal transducer and activator of transcription 3,STAT_(3))、维甲酸相关核孤儿受体γt(retinoic acid-related orphan receptorγt,RORγt)、叉头状转录因子P3(forkhead box P3,FOXP3)、转化生长因子β(transforming growth factorβ,TGF-β)、IL-10和IL-17水平;免疫荧光法检测FOXP3和IL-17A水平;Western blot法检测TGF-β1/FOXP3/RORγt信号通路关键蛋白表达水平。结果与模型组比较,芦荟多糖明显改善甲状腺组织病理学变化,降低血清TSH、TGAb、TPOAb、TNF-α、IL-1β和IL-17的水平(P<0.05),升高血清FT3、FT4和IL-10的水平(P<0.01),下调甲状腺组织STAT3、RORγt和IL-17水平(P<0.01),上调甲状腺FOXP3、TGF-β和IL-10水平(P<0.01)。结论芦荟多糖可能通过TGF-β1/FOXP3/RORγt信号通路对小鼠自身免疫性甲状腺炎具有较好的保护作用。

Objective To explore the protective effect of aloe polysaccharide on mice autoimmune thyroiditis based on TGF-β1/FOXP3/RORγt signaling pathway.Method Thirty 2-month-old female mice were randomly divided into the normal group,the model group and aloe vera polysaccharides group,with 10 mice in each group.Mice model of autoimmune thyroiditis were established by subcutaneous injection of porcine thyroglobulin(PTg)+high iodine water,in which aloe polysaccharide 300 mg/(kg•d)were given by gavage,and the other two groups were given the same amount of physiological saline.Four weeks after drug intervention,the pathological changes of thyroid gland in each group were observed by HE staining.The levels of FT3,FT4,TSH,TGAb,TPOAb,TNF-α,IL-1β,IL-10 and IL-17 in serum,and STAT3,RORγt,FOXP3,TGF-β,IL-10 and IL-17 in thyroid gland were detected by ELISA.The levels of FOXP3 and IL-17A were detected by immunofluorescence.The expression levels of key proteins in TGF-β1/FOXP3/RORγt signaling pathway were detected by western blot.Results Compared with the model group,aloe polysaccharide significantly improved the histopathological changes of thyroid gland,decreased the levels of serum TSH,TGAb,TPOAb,TNF-α,IL-1βand IL-17(P<0.05),increased the levels of serum FT_(3),FT_(4) and IL-10(P<0.01),downregulated the levels of STAT3,RORγt and IL-17 in thyroid gland,and upregulated the levels of FOXP3,TGF-βand IL-10 in thyroid gland(P<0.01).Conclusion Aloe polysaccharide may have a good protective effect against autoimmune thyroiditis in mice through TGF-β1/FOXP3/RORγt signaling pathway.