Using The Molecular Pathological Research, To Study The Apoptosis Mechanism Involved In Fas, P53 And Bcl-2 Of Polymyositis And Dermatomyositis

Objective: Polymyositis(PM), Dermatomyositis(DM) is a group of skeletal muscle diseases, acquired and related to autoim- mune. The clinical manifestation is characterized by proximal and symmetried muscle weakness and the creatine kinase elevated, with a subacute or acute onset. The majority of electromyogram(EMG) presents myogenic change, and partial DM patients show myogenic or neurogenic character. Massively degenerating, necrotic and regenerating muscle fibers are observed by pathological analysis of biopsied skeletal muscle. There are inflammatory cells infiltrated in endomysium, perimys- ium and around blood vessels in PM; DM is characterized by Perifascicular atrophy fibers, while degenerating and necrotic fibers are scattered. There are many inflammatory cells infiltrated in endomysium and perimysium, especially around the blood vessels. It was that a great number of etiological factor, the viral infection, heredity, cell immunity, humoral immunity, MHC molecule and cytokines, related to PM/DM. Overexpression of MHC classâ… molecule in muscle cells may be an initial factor of myositis, moreover, the persistence and development of myositis may due to abnormal immune reaction. Pathological change was well known that the main mechanism was humoral immune in DM and cell immune in PM. Various cytokines played an important role in the pathogenesis of PM/DM. In recent years, many scholars focused on the question if the apoptotic mechanic- sm was involved in the muscle fiber death and proteins related to apoptosis during the onset of PM/DM. To investigate the functions of protein related to apoptosis in PM/DM, using the pathological analysis of immunohistochemical stains, we studied the expression and distribution of apoptosis-inducing proteins (Fas, p53) and anti- apoptosis proteins(Bcl-2) in skeletal muscle of PM/DM at the molecular pathologyical level.Methods:1. According to diagnostic standard of Dalakas MC in 2003, muscle biopsy specimens of 10 patients with PM/DM were selec- ted as the case group, including four PM patients and six DM patients, while two nearly normal muscle specimens as the contr- ol group.2. Frozen serial sections, histochemical stain, anti-p53, Fas and Bcl-2 monoclonal antibodies immunohistochemical stains were performed for pathological analysis.Results:1 Clinical analysisOnset of an acute or subacute course, present proximal muscle weakness, spontaneous or palpatal mussle pain, while skin lesions can be observed in DM. The elevated creatine kinase range from 148 to 130,000 U/L. The electromyogram(EMG) of majority of patients present on myogenic change, the partial DM patients show myogenic or neurogenic character.2 Histochemistry pathological analysis in PM/DMPM: Massively degenerating and necrotic fibers are observed in HE and MGT. Inflammatory cells infiltrate in endomysium, perimysium, especially around blood vessel; Enzyme activity of NADH-TR is focally decreased; The activity of acid phosphatase (Acid) increases in degenerating muscle fiber and inflammatory cells.DM: Perifascicular atrophy fibers, and sparsely degenerateing necrotic fibers are observed in HE and MGT. Inflammatory cells infiltrate in endomysium, perimysium, especially around blood vessel; The enzyme activity of NADH-TR increase in perifasci- cular atrophy fibers; The activity of acid phosphatase increases in perifascicular atrophy fibers and inflammatory cells.3 The expression of the proteins related to apoptosis in PM/ DM3.1 Compared with the control group, the protein of Fas, P53 and Bcl-2 positively express in necrotic fibers in PM, characterised as brown cytoplasmatic. Regard as the expression on partial inflammation cells, Bcl-2 have marked positivity, characterised as brown, but Fas slightly in PM, characterised as stramineous.3.2 The protein of Fas, P53 and Bcl-2 positively expressed on perifascicular atrophy fibers in DM,characterised as brown cytoplasmatic, but there are not observed on inflammatory cells in DM.Conclusion:1 The pathological character of PM show that massively degenerating and necrotic fibers are observed and inflammatory cells infiltrate in endomysium, perimysium, especially around blood vessel. Perifascicular atrophy fibers are the distinctivly pathologic character in DM. Muscle biopsy and pathological analysis are an important method to diagnose PM and DM.2 Fas, P53 and Bcl-2 protein positively express on necrotic fibers of PM, consequently, It can be infered to apoptosisind- ucing proteins (Fas, p53) and anti-apoptosis proteins(Bcl-2) involveed in the pathology process of muscle cell death. Apoptotic muscle cells can partially develop to necrosis.3 Fas, P53 and Bcl-2 protein positively expressing on perifasc- icular atrophy fibers of DM suggest that perifascicular atrophy fibers are related to apoptotic mechanism. Bcl-2 protein possibly inhibites atrophy fibers developing to necrosis.4 In PM, marketly positive express of Bcl-2 protein and slight- ly positive express of Fas protein indicate that the anti-apoptosis function of Bcl-2 protein is stronger than apoptosis-inducing function of Fas protein in inflammatory cells. In conclusion, inflammatory cells existing on the diseased region show that PM is an unlimited disease proceeding inflammatory reaction.