Effcct Of C5b-9on Pathogenesis Of Necrotizing Myopathy

Objective:To explore the expression of C5b-9in the skeletal muscle of necrotizing myopathy，and investigate the contribution of C5b-9in pathological changes of muscle fiber andblood vessels.Methods:1.The13cases of selected patients fufill the criteria of necrotizing myopathy,andknown causes of necrotizing myopathy,including polymyositis and dermatomyositiswere ruled out.2.The clinical and neurophysiological manifestations were analyzed in13cases withnecrotizing myopathy, laboratory examination including blood biochemical and relatedimmunological test were measured,using SPSS13.0for statistical analysis.3.The expression of C5b-9was detected in the skeletal muscle of necrotizingmyopathy with enzymohistochemistry and immunohistochemistry.Results:1.Among13necrotizing myopathy cases,8cases（61.5%）were male and5cases（38.5%）were female.The average onset age of male patients was49.13±18.51,and theresults of female patients was48.4±16.13.The main clinical features were described asfollow: weakness of four limbs（84.6%）, weakness of both lower limbs（15.4%）;8patients with neck weakness and3patients with respiratory muscle weakness;7patientshad myalgia,6for proximal muscular atrophy. The average CK value of necrotizingmyopathy patients was4678.5±3449.05,and the average LDH value was1022.25±617.47IU/L.2. Focal or dispersive necrotic muscle fibers were observed in all patients,andphagocytosis of necrotic fibers was evident.There was no inflammatory cell infiltrationin perimysium and perivascular. Hematoxylin&eosin staining showed a decresased number of small blood vessels in local area,and the wall of individual small bloodvessel was thickened. Immunohistochemistry staining showed the expression of C5b-9was particularly prominent in the necrotic muscle fiber,and blood vessels were positivefor C5b-9, diffuse C5b-9expression on vascular endothelial cell and smooth musclelayer and the staining intensity was strong.Conclusion:.C5b-9was strongly expression on the necrotic muscle fiber and blood vessels,andcontribute to the pathogenesis of necrotizing myopathy.