EGCG对小鼠实验性自身免疫性脑脊髓炎的保护作用

Protective effects of EGCG in experimental autoimmune encephalomyelitis mice

目的观察绿茶提取物EGCG对实验性自身免疫性脑脊髓炎(EAE)小鼠的治疗作用及相关机制。方法取C57BL/6小鼠,随机分为对照组、EAE模型组和EGCG治疗组,对各组小鼠进行神经功能评分,并对中枢神经系统炎性浸润情况进行观察;流式细胞技术检测Th1、Th17细胞在中枢神经系统中频率变化;免疫组化观察25 d脑组织IFN-γ、IL-17和TGF-β的表达情况;ELISA检测血清中IFN-γ、、IL-17、TGF-β、IL-10、IL-4的质量浓度。结果 EGCG治疗明显缓解EAE小鼠疾病症状和中枢神经系统炎症,抑制Th1与Th17细胞向中枢神经系统浸润。与EAE模型组相比,EGCG治疗组脑IFN-γ及IL-17表达上调,而TGF-β表达下调;外周血中可溶性上述细胞因子表达情况与脑一致。结论 EGCG可能通过影响中枢神经系统及外周血中IFN-γ、IL-17、TGF-β的表达,调控T细胞亚群的分化对EAE发挥保护作用。

To evaluate the protective effects of epigallocatechin gallate （EGCG, green-tea extractive） against experimental autoimmune encephalomyelitis （EAE） and to investigate its mechanism, we established a EAE model in mice, and observed the pathological changes in model mice before and after EGCG treatment. C57BL/B mice were randomly divided into three groups： normal control group, EAE model group and EGCG treatment group, then the neurological defects of the mice in each group were evaluated and the inflammatory infiltration of brain and spinal cord tissue were examined by HE staining. The percentages of Thl and Thl7 cells in central nervous system were detected by flow cytometry; the expression of IFN-γ IL-17 and TGF-β in 25 d brain tissue were observed by immunohistochemical method, and the concentration of IFN-% IL-17, TGF-[3, IL-10 and IL-4 in mouse serum were detected by ELISA. Data showed that EGCG treatment could ameliorate the disease symptom and the inflammation in central nervous system of EAE mice. Compared with EAE model group, the IFN-γ and IL-17 expression in EGCG group increased and the TGF-β expression reduced in brain tissue, which was consistent with the change of soluble IFN-γ, IL-17 and TGF-β in peripheral blood. In conclusion, EGCG has protective effects in EAE mice, and the mechanism might relate to its influence on IFN-γ IL-17 and TGF-β expression both in central nervous system and in peripheral blood, and also relate to its regulation effect on T cell differentiation.