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Insulin-like growth factor I slows the rate of denervation induced skeletal muscle atrophy

2005; Elsevier BV; Volume: 15; Issue: 2 Linguagem: Inglês

10.1016/j.nmd.2004.10.013

1873-2364

Thea Shavlakadze, Jason D. White, Marilyn Davies, Joseph F. Y. Hoh, Miranda D. Grounds,

Neurogenetic and Muscular Disorders Research

Loss of the nerve supply to skeletal muscle results in a relentless loss of muscle mass (atrophy) over time. The ability of insulin-like growth factor-1 to reduce atrophy resulting from denervation was examined after transection of the sciatic nerve in transgenic MLC/mIGF-1 mice that over-express mIGF-1 specifically in differentiated myofibres. The cross sectional area (CSA) of all types of myofibres and specifically type IIB myofibres was measured in tibialis anterior muscles from transgenic and wild-type mice at 28 days after denervation. There was a marked myofibre atrophy ( approximately 60%) in the muscles of wild-type mice over this time with increased numbers of myofibres with small CSA. In the muscles of MLC/mIGF-1 mice, over-expression of mIGF-1 reduced the rate of denervation induced myofibre atrophy by approximately 30% and preserved myofibres with larger CSA, compared to wild-type muscles. It is proposed that the protective effect of mIGF-1 on denervated myofibres might be due to reduced protein breakdown.