Effect of spinal cord extract on the atrophy of denervated rat skeletal muscle / 体力科学

ABSTRACT

This study was undertaken to determine the effect of neurotrophic substance on atrophy of denervated rat skeletal muscle. Hind-limb muscles of 14-21-week-old rats were denervated and/or artery-ligated for 1 week. Some muscles were also injected with saline buffer or a saline extract of porcine spinal cord (10 mg protein/ml) daily via the femoral artery. Atrophy was assessed by measurement of muscle wet weight and cross-sectional area of type I, type II A and type II B muscle fibers. The results obtained were as follows<BR>1. Denervation produced a significant decrease in the weights of the gastrocnemius, soleus and extensor digitorum longus (EDL) muscles. It also significantly decreased the area of each fiber type in the lateral head of the gastrocnemius (deep portion) and soleus muscles.<BR>2. Artery ligation produced a significant decrease in the weights of the gastrocnemius and EDL muscles, but did not significantly change the area of each fiber type in the lateral head of the gastrocnemius (deep portion) and soleus muscles.<BR>3. Buffer injection did not change the weight or fiber areas of hind-limb muscles to a significant extent.<BR>4. Injection of spinal cord extract significantly ameliorated the atrophy of denervated EDL muscle.<BR>In conclusion, it is suggested that a substance present in the spinal cord may ameliorate the atrophy of denervated muscle in vivo.