中文摘要：

目的探讨重症肌无力（MG）的发病机制，为临床治疗提供一定的实验理论依据。方法将制备的MG患者胸腺细胞悬液分为对照组和实验组培养72h后，流式细胞术分析胸腺细胞Bcl-2分子的表达；MTT法测定细胞增殖、流式细胞术分析其凋亡的情况。结果雌、孕激素培养组胸腺细胞Bcl-2的表达率比空白对照组显著降低（P〈0．05）；雌、孕激素对细胞的增殖有明显抑制作用（P〈0．05），诱导其凋亡。结论雌、孕激素抑制MG患者胸腺细胞Bcl-2的表达，而且抑制胸腺细胞的增殖，诱导其凋亡；提示体内雌激素、孕激素水平变化与MG患者病情变化有一定联系。

英文摘要：

Objective To explore the pathogenesis of myasthenia gravis （MG） and provide some theoretical basis to therapy. Methods The cell suspension which was obtained from the thymus in patients with MG was subcultured in the culture template for 72 h. The expression of Bcl-2 in post-cultured thymocytes and the rates of thymocyte apoptosis after culture in the presence of each hormone were detected by flow cytometry （ FCM ）. Proliferation of thymocytes in patients with MG was analyzed througli MTT colorimetric analysis after culture with each hormone. Results The positive rates of Bcl-2 protein expression in thymocytes of MG patients were significantly lower in groups of estrogen, progesterone culture than in normal controls （P 〈 0.05 ） and significantly higher in group of thyroid hormone culture than in normal controls （ P 〈 0.05 ）. The proliferation of thymocytes was inhibited in the presence of estrogen, or progesterone and enhanced in the presence of thyroid hormone （ P 〈 0.05 ）. Conclusion Estrogen and progesterone inhibit the expression of Bcl-2 in the thymocytes in patients with MG and the proliferation of thymocytes; thyroid hormone enhances the expression of Bcl-2 in the thymocytes in patients with MG and the proliferation of thymocytes. There is probably a relation between the change of the level of estrogen and progesterone and the different disease conditions in patients with MG.