Light and electron microscopic study on the effect of training and high cholesterol diet on the skeletal muscle of male albino rat exposed to strenuous exercise

ABSTRACT

The present study aimed at investigating the effect of training and high cholesterol diet on the skeletal muscle [soleus] of male albino rat exposed to strenuous exercise [SE] immediately and 24 hours after. Eighty eight male albino rats were divided into 2 groups group 1 given balanced diet and group 2 given high cholesterol diet. Each group was subdivided into control rats not subjected to exercise and experimental group which included untrained and trained rats exposed to [SE] and sacrificed immediately or after 24 hours. Serum triglyceride [TG] and low density lipoprotein cholesterol [LDL-C] were tested. Semithin and ultrathin sections were examined by light and electron microscopes. Mean unclear area and count of sarcoplasmic vacuoles were assessed morphometrically. In group 1, nuclei with peripheral chromatin condensation, darkly stained fibers and electron dense areas were seen in untrained rats immediately following [SE]. Small nuclei with peripheral chromatin condensation, atypically arranged myofibrils, discontinuous A bands, focal loss of Z lines with electron dense particles around and enlarged,mitochondria with destroyed cristae were detected in untrained rat muscles 24 hours following [SE]. Less changes were noticed in corresponding trained rats. Group 2 revealed multiple sarcoplasmic vacuolations. Dark areas, irregular discontinuous myofibrils and small nuclei with peripheral chromatin condensation appeared in untrained rat muscle immediately following [SE]. In addition, small dark nuclei existed 24 hours after [SE]. Highly significant decrease in mean nuclear area and mean count of sarcoplasmic vacuoles existed in untrained and trained subgroups respectively. Dilated cisternae of sarcoplasmic reticulum, enlarged mitochondria with destroyed cristae and irregular focally disrupted sarcolemma were seen in untrained rats. Less changes were detected in corresponding trained rats. Serum [LDL-C] and [TG] showed highly significant increase in group 2 and highly significant decrease in trained subgroups. It was concluded that apoptosis was induced by strenuous exercise exacerbated by hypercholesterolemia and lessened by training