Association between dystrophin and neuronal nitric oxide synthase in muscles of progressive muscular dystrophy

Objective: To study the association between dystrophin and neuronal nitric oxide synthase in muscles of progressive muscular dystrophy patients and the role of deficiency of nNOS in pathogenesis of muscular dystrophy.

Methods: NADPH diaphorase enzyme histochemistry and anti-nNOS, anti-dystrophin, and anti-alpha, beta, gamma, delta-sarcoglycan antibody immunohistochemistry were used to analyze the muscle specimens from progressive muscular dystrophiy patients.

Results: Both nNOS and dystrophin were absent in the sarcolemma region of Duchenne muscular dystrophy (DMD) patients. Dystrophin was reduced, and nNOS was absent or reduced in the sarcolemma region of Becker muscular dystrophy (BMD) patients. Both nNOS and dystrophin were expressed normally in the sarcolemma region of limb girdle muscular dystrophy (LGMD) patients.

Conclusions: Deficiency of nNOS is associated with deficiency of dystrophin in the sarcolemma. Dystrophin may have a novel role in localizing nNOS to sarcolemma and regulating the expression of nNOS. Aberrant regulation of nNOS may contribute to degeneration of muscle fibers in DMD.