Biochemical and hislogical studies of nitric oxide (NO) in neuromuscular disorders.

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[1] Histological determination of nitric oxide synthase (NOS) and superoxide dismutase (SOD) in biopsied human muscle : Immunohistochemical analyzes were made of Mn-SOD in biopsied muscles. Mn-SOD was mainly present in subsarcolmmal region of ragged-red fibers in mitochondrial encephalomyopathies. Mn-SOD positive fibers may be of use for diagnosing mitochondrial encephalomyopathies. In addition, to determine localization of nitric oxide synthase in diseased muscle, immunohistochemical analyzes of neuronal-type NOS (nNOS) and endothelial-type NOS (ec-NOS) were performed. Immunostaining of nNOS was prominent in the sarcolemmal region of the ragged-red fibers. Ec-NOS was strongly positive in the myofibrils of ragged-red fibers. Findings suggest that SOD and NOS are important in the muscles of patients with mitochondrial encephalomyopaties. In polymyositis, necrotic or regenerating fibers showed poorly staining of nNOS and NADH-diaphorase staining.[2] Histological localization of NOS and d … More ystrophin related proteins in necrotic or regenerating fibers in skeletal muscle : A rat model for necrosis or regeneration of skeletal muscle fibers was prepared by cardiotoxin injection in rat skeletal muscles. Immunostaining of dystrophin, alpha sarcoglycan and alpha 1 syntrophin disappeared in necrotic muscle fibers, and reappeared in regenerating fibers after several days. Expression of dystrophin and alpha sarcoglycan tended to be earlier than that of in the regenerating process. In necrotic or regenerating muscle fibers of polymyostitis, immunostaining of dystrophin and alpha sarcoglycan was distinctly positive in the sarcolemmal region, while alpha 1 syntrophin and NOS poorly stained or did not stain.[3] Cytokine-induced expression of NOS in C2C12 skeletal muscle myocytes : To determine whether NOS production can be induced in skeletal muscle, i stimulated C2C12 mouse skeletal muscle myocytes with cytokines. Combinations of interferon-gamma, interleukin-1alpha, and tumor necrotic facter-alpha resulted nitrite production. Nitrite production was significantly reduced by the coincubation of cells with L-NAME during cytokine stimulations. The coincubation Cu/Zn-SOD,Mn-SOD or catalase also inhibited nitrite production with cytokine stimulations. Less