Histological Study on the Change in Skeletal Muscle Fibers after the Curting of Peripheral Nerve

Abstract

The atrophy of muscle fibers after the cutting of N. fibularis profundus to M. tibialis ant. was studied histologically by making a distinction among red muscle fibers, medium muscle fibers and white muscle fibers. The experimental animals, Wistar-strain rats, were devided into two groups, namely the nerve-cutting group and the control group. In the nerve-cutting group, N. fibularis profundus was cut on the 70 days after birth. M. tibialis ant. was removed on the 10 days and 20 days after the cutting of nerve. The histological method, using Sudan black B stain, was adopted. The results obtained were as follows : 1) No apparent effect of the nerve cutting on the rats' body weight could be observed. 2) The decreasing rate of the weight of M. tibialis ant. was 28.4% on the 10 days and 39.8% on the 20 days after the nerve cutting. 3) In the group of the 10 days after the nerve cutting, the decreasing rate of the entire area of cross section at the middle part of M. tibialis ant. was 19.3% in red muscle fibers, 34.7% in medium muscle fibers, and 43.7% in white muscle fibers. 4) The effect of the nerve cutting on the average area of cross section per fiber showed the same tendency as that on the entire area of cross section in red muscle fibers, medium muscle fibers and white muscle fibers.