实验性自身免疫性重症肌无力大鼠T淋巴细胞IFN-γ及其受体表达水平的研究

Expressions of IFN-γ and Its Receptor on T Lymphocyes of Rats with Experimental Autoimmune Myasthenia Gravis

目的探讨实验性自身免疫性重症肌无力(EAMG)大鼠T淋巴细胞γ-干扰素(IFN-γ)的分泌及其表面IFN-γ受体(IFN-γR)的表达水平。方法健康、雌性Lewis大鼠24只,随机分为正常对照组、完全福(氏)佐剂(CFA)对照组、EAMG组。EAMG组大鼠分别于足垫、腹部及背部皮下多点注射丁(氏)双鳍电鳐的电器官乙酰胆碱受体(AChR)蛋白乳剂1 mL,第4周再次注射上述乳剂免疫大鼠。CFA对照组只接受等量的CFA皮下注射。初次免疫后7周,分离各组大鼠脾脏T淋巴细胞并体外培养48 h后,应用ELISA和免疫组织化学方法分别检测T淋巴细胞IFN-γ分泌及其表面IFN-γR的表达水平。结果(1)正常大鼠T淋巴细胞体外培养48 h后,其上清液中IFN-γ水平很低,而EAMG组大鼠T淋巴细胞培养上清液中IFN-γ水平较CFA对照组与正常组显著增高(P<0.01);(2)正常大鼠T淋巴细胞经过体外培养后可见少量IFN-γR阳性细胞,而EAMG组大鼠T淋巴细胞经体外培养后可见较多IFN-γR阳性细胞,其阳性细胞数及其平均吸光度D(λ)值均明显高于CFA对照组与正常组(P<0.01)。结论EAMG大鼠T淋巴细胞IFN-γ分泌及其表面IFN-γR表达水平明显升高,IFN-γ/IFN-γR的异常表达可能在重症肌无力(MG)的发生过程中发挥重要作用。

Objective To investigate the expressions of IFN-γ and its receptor on T lymphocytes in rats with experimental autoimmune myasthenia gravis （EAMG）. Methods Twenty-four healthy, female Lewis rats were divided into 3 groups randomly., normal group, EAMG group, and completed Freund＇s adjuvant （CFA） group. The rats were immunized with the AChR protein extracted from electric organ of Narcine timilei and CFA in the EAMG group, or only with CFA in CFA group. The clinical manifestations were observed every day. At the 7 th week after first immunization, T lymphocytes in every rat were separated from the spleen. After cultured for 48 h, the content of IFN-γ in the supernatants were detected by enzyme-linked immunoadsordent assay （ELISA）, and the expression of IFN-γ receptor on the T lymphocytes were examined using immunohistochemical method. Results （1） The content of IFN-γ in the supernatants was low in the normal group, and increased markedly in EAMG group （P〈0. 01）. （2） Compared with the normal group rats, the IFN-γ receptor positive cells were significantly increased in EAMG rats （P〈0.01）. Conclusions The content of IFN-γ and the expression of IFN-γ receptor on T lymphocytes are increased in the rats with EAMG might play a role in the pathogenesis of the onset and maintenance of myasthenia gravis.