Abstract:

Objective   To investigate the effects of A3 adenosine receptor(A3AR)expression in the pathogenesis of idopathic inflammatory myopathies( IIMs). Methods   Muscle tissues from 30 cases of IIMs including 15 cases of dermatomyositis(DM), 11 cases of polymyositis(PM), 4 cases of inclusion body myositis(IBM) and 12 cases of normal controls were collected. Histochemical staining and immunofluorescent staining of the A3AR antibody were used to detect the existence of A3AR in the muscle biopsies． Results   The cytosolic immunofluorescent staining of A3AR antibody was positive in the type Ⅱ muscle fibers, however, the staining was absent in the typeⅠmuscle fibers. 22 cases among the 30 cases of IIMs displayed a more intense cytosolic staining compared with that of the controls. Cell membrane fluorescent staining was positive in 19 cases of the IIMs, but it was negative in the controls. The highest intensity of the immunofluorescent staining for the A3AR antibody was localized in vascular smooth muscles and some necrotic fibers. Conclusions   The A3AR expresses in human type Ⅱ skeletal muscle fibers. Expression of A3AR increases in idopathic inflammatory myopathies (IIMs) patients, and it may have a bidirectional regulation in the repairing and apoptosis of muscle fibers.

Key words: Receptors, purinergic P1; Myositis; Biopsy, muscle