PRESERVATION OF DENERVATED MUSCLE BY SENSORY PROTECTION IN RATS

The goal of this study was to determine whether sensory motor nerve cr ossover could alter post-denervation atrophy of skeletal muscle. Sixty adult Lewis rats were divided into three groups: 1) unilateral transe ction of the tibial nerve alone; 2) unilateral transection of the tibi al nerve with immediate repair; and 3) unilateral tibial and sural ner ve transections with repair of the proximal sural nerve (sensory) to t he distal tibial nerve (motor). The unoperated hind legs acted as posi tive controls. At 1 and 2 months postoperatively, posterior compartmen t musculature was harvested, weighed, then fixed and stained for histo logic analysis. One month postoperatively, mean muscle weight in Group 1 animals (transection alone) was 23.0 +/- 2.6 percent of the control side; for Group 2 animals (motor-motor repair) was 40.9 +/- 42 percen t; and for the sensory-protected Group 3 animals (sensory-motor repair ) was 26.7 +/- 2.8 percent of controls (n = 15 per group). Two months postoperatively, the mean weights were 14.5 +/- 0.9 percent, 58.8 +/- 7.3 percent, and 21.1 +/- 3.1 percent of controls for Groups 1, 2, and 3, respectively (n = 5 per group). Differences between groups were st atistically significant. Histologic analysis of Group 1 specimens reve aled generalized atrophy of all muscle fibers. In Group 2, specimens s howed evidence of reinnervation and less atrophy. Group 3 specimens de monstrated an atrophic pattern with islands of non-atrophic Fibers sca ttered throughout. Sensory protection was thus shown to have a signifi cant effect on post-denervation atrophy in rat skeletal muscle.