Bcl-2 and Bax protein expression in human myopathies.
Expression of the apoptosis-related proteins Bcl-2 and Bax was analysed by means of immunohistochemistry in muscle biopsies from 13 patients suffering from different muscular diseases (inclusion body myositis n=4, polymyositis n=3, Becker muscular dystrophy n=4, necrotizing myopathy n=2, and controls n=4), in an attempt to learn about the role of these proteins in human muscle diseases associated with muscle fiber necrosis and regeneration. Increased Bcl-2 and Bax immunoreactivity was observed as fine granular precipitates in the cytoplasm or as subsarcolemmal aggregates in pathological cases. Increased Bcl-2 and Bax immunoreactivity was detected in some necrotic fibers, regenerating fibers, ring fibers and some apparently normal muscle fibers. In addition, increased Bcl-2 and Bax immunoreactivity was observed in the periphery of rimmed vacuoles and in muscle fibers with abnormal mitochondria in patients suffering from inclusion body myositis. Double-labelling immunohistochemistry disclosed co-localization of both proteins in about 50% of Bcl-2-immunoreactive fibers. Finally, double-labelling immunohistochemistry using N-CAM antibodies revealed that some Bax-positive fibers were regenerating fibers. Since increased Bax immunoreactivity was not restricted to necrotic muscle fibers, the present results suggest that over-expression of this protein in human myopathies is probably independent of the process of cell death.
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Servicio de Neurología, Hospital Príncipes de España, Barcelona, Spain.
Ferrer
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D000293:Adolescent; D000328:Adult; D000368:Aged; D001706:Biopsy; D053938:DNA Fragmentation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000473:pathology; D009135:Muscular Diseases / Q000378:metabolism* / Q000473:pathology; D011518:Proto-Oncogene Proteins / Q000032:analysis* / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000032:analysis* / Q000378:metabolism; D051028:bcl-2-Associated X Protein
C494826:BAX protein, human; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein