Expression of myostatin RNA transcript and protein in gastrocnemius muscle of rats after sciatic nerve resection.

Myostatin, a member of the transforming growth factor-beta (TGF-beta) superfamily, has been identified as an inhibitor of skeletal muscle mass. To have an insight into the expression pattern of myostatin and its potential role in skeletal muscle atrophy induced by denervation, we used an animal model of peripheral nerve resection to examine the time-dependent changes in myostatin mRNA and protein levels in the denervated gastrocnemius muscle of rats after sciatic neurectomy by the aid of quantitative real-time RT-PCR and Western blotting, respectively. We also conducted morphometric analyses to measure the wet weight ratio of the denervated muscle (the operated side/contralateral non-operated side) and the cross sectional area of muscle fibers and to observe muscle morphology. The experimental results showed that myostatin mRNA and protein levels in rat gastrocnemius muscle persistently elevated after denervation, despite a fluctuation of myostatin mRNA level at day 3 after denervation, reached their respective peaks at day 28 after denervation, and then depressed slightly until day 56 after denervation. Furthermore, a significant negative linear correlation was found between myostatin abundance and muscle atrophy degree, suggesting that myostatin might probably play an important role in denervation-induced muscle atrophy. Our present study perhaps provides a new window into myostatin regulation in association with a specific type of muscle atrophy.