10例进行性肌营养不良肌肉组织活检的电镜观察

Ultastructural changes of the muscle tissues from the patients with advanced muscular dystrophy

目的 探讨进行性肌营养不良的发病机理及诊断。方法 对 10例不同临床类型的进行性肌营养不良症的腓肠肌活检标本进行了光镜和电镜观察。结果 在所有的标本中肿胀肌纤维与萎缩肌纤维混合存在 ,大量的小泡多见于前者肌浆中。局灶性微孔肌浆膜的出现常见于该病症的早期。随病程进行 ,肌浆膜有片状缺失。常见肌纤维间、原纤维间、微丝间和肌浆内水肿变性。多见线粒体肿胀、嵴断裂、消失及结晶样包含物的出现 ,同时见到肌浆网扩张。二者同积聚的糖原常充填于肌溶灶处。在病变早期肌原纤维的微丝显出排列紊乱 ,相邻原纤维的Z线不在一条水平线上排列 ,Ⅰ带变宽 ,肌小体增长。最后受损肌原纤维溶解 ,断裂和凝固性坏死 ,随后单核细胞入侵。结论 虽然临床上将本病症分为若干类型 ,但所有标本中的类型未见有特异性的超微结构改变 ;微孔肌浆膜的早期出现是该病的主要特征。本文最后还就肌浆膜的破损、Dystrophin(肌营养不良蛋白 )

Objective To observe the morphological alterations of the calf muscle from advance muscular dystrophy and to explore its diagnostic criteria. Methods Ten cases of the muscle biopsies were studied with light and electron microscopes. Results Both swollen myofibres with vacuoles and atrophy ones were observed in all the cases. One of the early common findings was appearance of porous sarcolemma, followed by sheet loss of the sarcolemma consequently. Hydropic degeneration occurred then between myofibres, myofibrils and myofilements, and within the sarcoplasm. Meanwhile, swollen mitochondria with broken cristae and/or crystalloid inclusion, dilated sarcoplasmic reticulum and aggregation of glycogen particles were present in the degenerated areas. The early alterations in myofibrils revealed disorderly arrangement of the filaments, out of alignment of Z-lines , and extension of I bands and sacromere. In the advanced stage, the affected myofibrils showed lysis, fragmentation and coagulation necrosis, followed by infiltration of mononuclear cells. Conclusions There is no type-specific alterations found in all the specimens, as many types of the disease has been divided in clinical practice. However, appearance of porous sarcolema is valuable for the diagnosis of the disease in early stage. The correlation between abnormality of myofibrils, decreased level of dystrophin and etiology of the disease is discussed.