ABSTRACT
This study aimed to detect the effect of Zocor [example of statins] and Lipanthyl [example of fibrates] on the skeletal muscle of male albino rats at the ultrastructural level. For this purpose sixty male albino rats were encountered and were subdivided into five groups. G1 was the control group [20 rats]; and other four groups 10 rats each. G2 received Zocor 0.72 mg/200 mg orally equivalent to the therapeutic dose in adult human and G3 received Lipanthyl 5.4mg/200g orally equivalent to the therapeutic dose in adult human. G4 was the recovery from Zocor intake and G5 was the recovery from Lipanthyl intake. For each group both semithin and ultrathin sections of LS of skeletal muscle were examined. Measurements of the myofibril diameters, average mitochondrial diameters in addition to the counting of the mitochondrial number were done using the image analyzer. The ultrastructural findings in G2 included marked myofibril degeneration in the form of loss and distortion of myofibrils. Mitochondria showed significant decrease in their number and very highly significant increase in their diameters. The nuclei of the muscle fibers appeared either swollen or shrunken, while those of satellite cells appeared shrunken and heterochromatic. G3 demonstrated a mixture of both degenerative and repair processes. The nuclei of satellite cells appeared either heterochromatic or euchromatic. There were focal loss of the myofibrils with very highly significant increase in the mitochondrial number and dilated sarcoplasmic reticulum. G4 showed highly significant decrease in the myofibril diameters compared to the control with the regaining of continuity and organization. G5 demonstrated non significant decrease in the myofibril diameter compared to the control. The present study concluded that Zocor had more damaging effect on skeletal muscle than Lipanthyl. Fortunately these myofibril changes were reversible after the stop of the drugs. It also concluded that the choice of hypolipidemic therapy needs to be based not only on the outcome evidence and cost-effectiveness analysis, but also on safety considerations for the individuals