【摘要】 目的 :探讨重症肌无力 (MG)胸腺细胞凋亡异常、Fas表达异常在自身免疫应答形成中的作用。方法 :用手术切除的MG患者的胸腺 ,制备胸腺提取液和胸腺细胞悬液 ,用MTT比色法测定胸腺细胞的增殖 ;用DNA电泳及细胞形态学观察细胞凋亡 ;用流式细胞仪检测细胞表面Fas的表达 ,用RT PCR结合单链多态构象性分析 (SSCP) ,探讨Fas基因的转录及可能存在的Fas基因突变。结果 :MG患者的胸腺提取液 ,能抑制正常胸腺细胞增殖 ,但不能抑制MG患者胸腺细胞增殖。在地塞米松作用下 ,正常人及患者胸腺细胞的增殖均可被抑制 ,细胞增殖抑制率分别为 5 8.33%和 5 4 .2 6 %。MG患者胸腺细胞的DNA电泳可见梯状条带 ,并且胸腺细胞上Fas的表达百分率增加 [(2 0 .38± 6 .0 7) % ],与空白对照组 [(12 .4 3±4 .32 ) % ]相比较P <0 .0 5。对MG患者胸腺细胞FasmRNA进行RT PCR SSCP分析 ,部分MG患者出现异常电泳条带。结论 :MG患者胸腺细胞的凋亡及Fas分子表达均异常 ,而且存在Fas基因突变 ,提示与本病的发生发展有关。更多还原

【Abstract】 AIM: To explore the roles of abnormalities of thymocytic abnormal apoptosis and its Fas expression in patients with myasthenia gravis(MG) in generation of autoimmune response . METHODS: The thymocytes were isolated and thymus extractive was prepared from fresh thymic tissue excised from MG patients. The proliferation of thymocyes was evaluated by MTT colorimetry. The apoptosis of thymocytes were examined by DNA electrophoresis. Expression of Fas was analyzed by a FACScan flow cytometry. Transcription and mutation of Fas gene were detected by RT PCR and single stranded conformation polymorphism(SSCP) analysis. RESULTS: Thymus extractive could inhibit proliferation of normal thymocytes, while had no influence on the thymocytic proliferation of MG patients. The proliferation of thymocytes of both normal persons and MG patients could be inhibited by thymus extractive in the presence of dexamethasone. The inhibition rates were 58.33% and 54.26% respectively.The cocultured thymocytes with dexamethasone showed characteristic apoptosis pattern and the DNA electrophoresis exhibited ‘ladder’ appearance. The abnormal bands in Fas mRNA of partial MG patients’ thymocytes were found by RT PCR SSCP analysis. CONCLUSION: Abnormalities of apoptosis and Fas gene expression of MG patients’ thymocytes, and Fas gene mutation may be related to the pathogenesis and progression of MG.更多还原