[Apoptosis and myopathies].

Recently a new type of cell death, apoptosis, was reported in the biological and many other fields. In an attempt to determine whether the Fas-Fas-ligand mediated apoptosis operates in the pathologic process of human myopathies, we examined the expression of Fas antigen, the synthesis of Fas-ligand mRNA, and the presence of chromosomal DNA fragmentation in the muscles from patients with various human muscle disorders. The Fas antigen of a whole molecule that can transduces the apoptotic signal into the cytoplasm was expressed on the muscle fibers of patients with various muscle wasting diseases. Its expression on muscle fibers was not disease specific, and the frequency of it becomes high according to the extent of the alteration of the muscle pathology. However, there was no evidence of operating the apoptotic process, that is no DNA fragmentation by TUNEL method. Furthermore, no Fas-ligand synthesis was detected in the diseased muscle tissue by RT-PCR method. Our data suggest that the expression of Fas antigen on muscle fibers in diseased muscles might be related to unknown biological functions other than "apoptosis" in the process of muscle fiber injury.