DIRECT-CURRENT STIMULATION OF CRUSHED NERVE INCREASES CAPILLARY DENSITY IN RAT MUSCLE

We studied the effect of direct-current (DC) stimulation of the crushe d sciatic nerve on capillary density and fiber diameter in the rat ext ensor digitorum longus (EDL) muscle. The cathode was placed distal to the site of axonotmesis of the left sciatic nerve, and the current was applied continuously for 35 days. Right legs were left intact and ser ved as controls. The animals were assigned at random to one of the fol lowing groups: (1) a cathode-stimulated (CA) group; (2) a sham-operate d (SH) group in which a stimulator gave no measurable current; and (3) an axonotmesis-only group, without a stimulator (AX). Only the CA gro up had a significantly reduced muscle-fiber diameter (p <.01) and a si gnificantly increased capillary-to-muscle fiber ratio (p <.03) as comp ared with the control site. A denser capillary network, in the EDL mus cles of CA-stimulated animals, could promote a more efficient delivery of oxygen and contribute to reduction in the overall time of muscle-f orce recovery after nerve crush, which we reported previously.