结缔组织生长因子在进行性肌营养不良中的表达

目的探讨结缔组织生长因子（CTGF）在进行性肌营养不良（PMD）中的作用。方法使用Duchenne型肌营养不良（DMD）8例、Becker型肌营养不良（BMD）2例、先天性肌营养不良（CMD）6例患儿的肌肉活检标本,借助免疫组织化学、双免疫荧光方法及Western印迹分析检测CTGF的免疫表达和定位。结果免疫组织化学和双免疫荧光法显示CTGF在正常肌肉的血管处明显表达;免疫组织化学法和Western印记分析均显示在PMD的萎缩肌肉中CTGF的免疫反应明显增强,所有病变肌肉组织中,CTGF在再生纤维的膜、胞浆及胞核中、巨噬细胞及巨噬细胞浸润的坏死纤维中强烈表达,也免疫定位在非再生纤维的肌纤维膜、肌内膜及肌束膜的结缔组织中;双免疫标记显示在肌内膜及肌束膜的大多数激活的成纤维细胞表达CTGF;但年长的CMD患儿的晚期纤维化中CTGF弱表达或无表达。结论结果表明CTGF可能参与了PMD的发病过程,肌肉内的CTGF可能在肌纤维再生和肌肉纤维化的病变过程中起重要作用。

Expression of connective tissue growth factor in progressive muscular dystrophy

Objective Progressive muscular dystrophy(PMD) is characterized by muscle fiber necrosis, regeneration, and endomysial fibrosis. Although absence of dystrophin and subsarcolemmic protein has been known as the cause of muscle fiber degeneration, pathogenesis of interstitial fibrosis is still unknown. The aim of this study was to investigate the role of connective tissue growth factor (CTGF) in PMD and its relationship with muscular fibrosis. Methods Immunological localization of CTGF was examined in frozen muscle specimens obtained via biopsy from 8 patients with Duchenne muscular dystrophy (DMD), 2 patients with Becker muscular dystrophy (BMD), 6 patients with congenital muscular dystrophy (CMD) and 6 cases with normal muscle by immunohistochemistry, double immunofluorescence and Western blot analysis. Results The results of immunohistochemistry and double immunofluorescence showed that CTGF was positive only in vessels of normal muscle. Both immunohistochemistry and Western blot analysis showed that CTGF expression was distinctly increased in dystrophy muscles of PMD than that in normal muscles. In dystrophy muscle, marked immunostaining of CTGF was not only observed in vascular walls, but also strongly expressed in the cytoplasm and nuclei of regenerating muscle fibers, and also immunolocalized in the muscle fiber sarcolemma of non-regenerating fibers. Double labeling with antibodies against CTGF and CD68 demonstrated that CTGF was expressed in some macrophages and some macrophage infiltrated necrotic fibers. CTGF was strongly expressed in endomysial and perimysial connective tissues of dystrophy muscles of patients with DMD, CMD and FCMD. Double immunolabeling revealed that most activated fibroblasts in perimysium and endomysium were positive for CTGF, but not all of connective tissues were co-localized with CTGF. Older cases with FCMD showed poor or no expression of CTGF in advanced fibrosis. Conclusion CTGF may play a role in the pathogenetic process of muscular dystrophy, and CTGF may be important for muscle repair and fibrosis.