MELAS患者肌细胞线粒体自噬异常的研究  

The dysfunction of mitophagy in the myofibers of patients with MELAS

作　　者：朱暄[1] 张世彬 陈庆国 朱敏[1] 郑俊俊 朱元昭 黄经纬[1] 洪道俊[1] 

机构地区：[1]南昌大学第一附属医院神经科,330006 [2]江西省玉山县中医院 [3]江西省高安市人民医院

出　　处：《中国神经免疫学和神经病学杂志》2015年第5期320-324,共5页Chinese Journal of Neuroimmunology and Neurology

基　　金：江西省自然科学基金(20142BAB205027);江西省教育厅科技项目(GJJ13128)

摘　　要：目的探讨线粒体脑肌病伴高乳酸血症和卒中样发作综合征(mitochondrial encephalomyopathy,lactic acidosis and stroke like-episodes,MELAS)患者肌细胞内线粒体自噬异常的改变。方法纳入2013-01-2014-06在作者医院就诊的7例MELAS患者,所有患者均行骨骼肌活检和线粒体DNA扩增后限制性内切酶基因检测。对患者的肌肉标本进行LC3、Beclin1、Bcl-2、Bax蛋白的免疫组化和免疫印迹检测。结果患者肱二头肌活检显示肌肉中出现数量不等的破碎肌纤维,表现为破碎红肌纤维和破碎蓝纤维,以及肌间小血管管壁深染。免疫组化染色显示LC3、Bcl-2、Bax蛋白在破碎肌纤维中呈阳性表达,而Beclin1呈阴性表达。肌肉活检组织免疫印迹检测显示LC3-Ⅰ表达升高,而LC3-Ⅱ表达下降;Beclin1表达无改变;Bcl-2和Bax表达升高;LC3-Ⅱ/LC3-Ⅰ和Bcl-2/Bax比值下降。结论 MELAS病变肌纤维的线粒体存在自噬障碍,造成大量功能和形态异常的线粒体不能被及时清除而堆积在细胞中,进而可导致细胞凋亡。Objective To explore the dysfunction of mitochondrial autophagy in patients with mitochondrial encephalomyopathy, lactic acidosis and stroke like-episodes （MELAS）. Methods Seven patients with MELAS were collected in our clinical center from January 2013 to June 2014. All the patients underwent muscle biopsy. The mitochondrial DNA （A3243G and G13513A） was amplified by polymerase chain reaction （PCR）. Microtubule-associated protein 1A/1B-light chain 3 （LC3）, Beclinl, B-cell lymphoma-2 （Bcl-2）, and Bcl-2-associated X （Bax） proteins in muscle specimens were detected by immunohistochemistry and Western blot. Results Muscle biopsy showed that ragged red fibers, ragged blue fibers, and stained succinate dehydrogenase （SDH） vessels presented in affected myofibers. Immunohistochemieal staining showed that the ragged fibers had strong immunopositivity to LC3, Bcl-2 and Bax, but negative to Beclinl. Western blot revealed increased level of LC3-Ⅰ ; decreased level of LC3-Ⅱ ; unchanged level of Beclinl ; increased level of Bcl-2 and Bax; and decreased ratios of LC3-Ⅱ/LC3-Ⅰ and Bel-2/Bax in the detected muscles. Conclusions Dysfunction of mitochondrial autophagy can be observed in myofibers of MEI.AS, which makes the affected myofibers transfer to apoptosis pathway.

关 键 词：MELAS 线粒体自噬 LC3 凋亡 

分 类 号：R746.9[医药卫生—神经病学与精神病学]