The Contribution Of Ezrin In Human Skeletal Muscle Fibers Regeneration

Skeletal muscle was the important tissue to maintain the human nomal vital movement. Skeletal muscles had a vigorous regenerative capacity in response to chemical, mechanical or physical injuries. Aregeneratory after necrosis and dysmaturity during the muscle fiber development process were the aetiology foundation of the amyotrophy and amyasthenia. There were the key points that we investigated the muscle fiber regenerative process and regenerative coherent factors, comprehend agents that promoted and controlled muscle fiber regeneration, explored the correlated conditions that promoted muscle recovery after injury.Ezrin had close correlation with tumor metastasis and it could assign tumor hypsi-transfer activity. There was increasing evidence that it regulated tumour. Therefore, we presumed the protein concerned with the tissue hyperplasy and migration-neoplastic formation and metastasis .This conducted us to research if ezrin had relation with the muscle fiber regeneration.At present, there were seldom researches about the regulatory mechanism of human skeletal muscle regeneration in our country, and the research concentrated regulatory factors effects in muscle fiber regeneration abroad. The focal point about ezrin focused on the regulation of tumor metastasis. Up to now, there was no report thatezrin regulated skeletal muscle fiber regeneration. The experiment initially approached the mechanism of human skeletal muscle fiber regeneration through research the contribution of ezrin in this process.We choosed the biopsy muscle preparation that the necrosis and regeneration were vigrious through light microscope ,including Duchenne's type muscular dystrophy(DMD) 9 cases, Becker type muscular dystrophy(BMD) 2 cases limb girdle type muscular dystrophy(LGMD)3cases,dermatomyositis(DM)3cases, polymyositis (PM) 2 cases, serious myopathy 1 case and contrast control (nearly nomal) 1 case . We made the muscle preparation continuous frozen sections 7 micrometer by the freezing microtome. Then, progressing HE, Acid phosphatase histochemical stains and Monoclonal antibody immunohistochemistry stains. The monoclonal antibody involved anti-NCAM, anti-ezrin, anti-desmin. We observed the regenerative muscle fiber, looked for the homologization muscle cell and studied the expression of regenerative muscle fiber after immunohisto- chemistry stains, and pathological analysis.We could mark the regenerative muscle fiber through HE stain, anti-NCAM and anti-Desmin immunohistochemistry stains. The HE stain: cell shapes were irregularity, endochylema was basophilia anachromasis, and cell nucleuses were big. The anti-NCAM monoclonal antibody immunohistochemistry stain: the regenerativemuscle fibers were anachromasis. The anti-desmin monoclonal antibody immunohistochemistry stain: which muscle fibers were anachromasis showed that they contained competent satellite cells and possessed regeneration capacity.We could observe ezrin expressed in skeletal regenerative muscle fibers through the experiment. Ezrin significantly expressed in regenerative muscle fibers of DM, PM and DMD, but expressed quietly in BMD. Acid phosphatase histochemical stain was the characteristic stain of inflammatory reaction, and anachromasis in intensive necrosis focus and the place of inflammatory cell infiltrate. The regeneration and inflammatory reaction were active in inflammatory myopathy including PM and DM, this showed that skeletal muscle regernertion had closely relation with inflammatory reaction. Ezrin significantly expressed in the place of athletic inflammatory reaction. Ezrin expressed no patency in LGMD and BMD.Through the experimental result we analyzed that Ezrin was the member of ERM family (ezrin, radixin, moesin and merlin), linked the plasma membrane with the actin cytoskeleton and regulate cell shape, motility, adhesion, and participate in cell migration, signal transduction and caryocinesia .Ezrin was also the intracytoplasm intracytoplasm connectin, and could regulate the alteration of cystoskeleton by many ways and participate in cell activity.Calpain was the cystoskeleton adjuster. It could positively regulate the myoblasts migration and make them so ordered arrangement that could fuse together perfectly, especially in the initial stage of confluence. So calpain played important role in the course of cystoskeletons recombinated, and it could effect cell shape, activity, adhesion, thus influence regeneration. Calpastatin was the endogenous inhibitor of calpain. It could inhibit inter- affinity of calpains, thus inhibit the fusion of myoblasts. The fusion of myoblasts into myotubes was completely prevented in cells that overexpressed calpastatin, strengthening the idea that calpains played a pivotal role in the initiation of myoblast differentiation. Calpastatin was capable of preventing fusion and confirmed the importance of the calpain–calpastatin ratio during myoblast differentiation.Ezrin had closely relationship with calpain–calpastatin system. It was one substrate of calpain, It was upregulated in calpastatin-overexpressing cells. These showed that ezrin was specificly regulated. The research papers predicted that calpain inhibition should result in an increase in steady-state ezrin levels, due to inhibition of basal cytoskeletal remodeling .These suggested that ezrin maybe had similar function with calpain, and played a role in the pieod of myoblasts fusion in the course of skeletal muscle fiber regeneration.Inflammatory reaction could stimulate the muscle fiber regeneration, maybe because inflammatory factors could secrete some myogenic regulatory factors. Macrophages could make satellite cells activation,on the one hand,they could clear necrotic muscle fibers,on the other hand ,they could secrete factors to selectively stimulate myogenic cells hyperplasy and differentiation , accordingly start the regeneration.Ezrin mediated actin polymerizing on phagosome , accordingly reinforce macrophages cytophagocy- tesis .Surrounding the muscle fiber necrosis focus, macrophages assembled and Ezrin were abundant on phagosome, therefore, immunohistochemistry stains were anachromasis. There were still some researches indicated that ezrin can make cystoskeleton rearrangement, and strengthen the ability of T cell conjugated antigen, and educe more effective immune response. So ezrin possibly stimulated muscle fiber regeneration coordinating with inflammatory cells.We could make these conclusions:Ezrin maybe had closely relationship with human skeletal muscle fiber regeneration. Ezrin maybe had similar function with calpain, and played a role in the course of the fusion of myoblasts, especially in earlier period. Skeletal muscle regeneration had intimately relation. Ezrin maybe had relation with inflammatory reaction. It possibly stimulated muscle fibers regeneration coordination with inflammatory cells.