重症肌无力易受累肌群乙酰胆碱受体的研究

Acetylcholine receptor content in muscles likely involved in myasthenia gravis

目的 通过对大鼠不同肌群乙酰胆碱受体形态学观察和含量测定,探讨自身免疫性重症肌无力肌群易受累的原因.方法 分离正常大鼠膈肌、腓肠肌、肋间肌、胸锁乳突肌、心肌、眼肌、咀嚼肌和前肢肌等8组肌群,进行免疫荧光染色,激光共聚焦显微镜观察乙酰胆碱受体（AChR）形态;实时荧光定量聚合酶链反应（FQ-PCR）法比较AChRβ1亚基基因含量.结果 8组肌群均可见红色AChR、绿色神经纤维和突触囊泡;8组肌群中AChRβ1亚基的表达量之间差异有统计学意义（F =395.1,P＜0.05）,组间比较腓肠肌（25.49 ±0.31）、肋间肌（24.42±0.75）、胸锁乳突肌（22.20±1.23）、咀嚼肌（11.22 ±0.80）、眼肌（1.46±0.11）之间差异有统计学意义（P＜0.05）.结论 大鼠各肌群AChR含量的不同与累及不同肌群的重症肌无力发病率明显相关,可部分解释重症肌无力患者发病后肌群受累顺序.

Objective To observe acetylcholine receptor （AchR） morphology and content of different muscles in rats,and explore the reasons of myasthenia gravis muscles likely involved.Methods Respectively,we harvested diaphragm,gastrocnemius,intercostal muscle,sternocleidomastoid,myocardial,musculi oculi,cardiac muscle,forelimb in normal rats,and immunofluorescence staining and laser confocal microscopy were used to observe AChR patterns.Results （1） Nerve fibers （green） and AChR （red） could be observed in all the muscles.（2） Among the muscles,AchRβ1 content showed obvious difference （F =395.1,P ＜ 0.05）.The content of AchR contents showed an decreased tendency as follows：gastrocnemius （25.49 ± 0.31）,intercostal muscle （24.42 ± 0.75）,sternocleidomastoid muscle （22.20 ± 1.23）,chewing muscle （11.22 ± 0.80）,and musculi oculi （1.46 ± 0.11）.Conclusion The incidence of rat muscle weakness and its different AChR content has some relevance,which can partialy explain the order of onset of muscle involvement in myasthenia gravis.