Introduction: Anabolic androgenic steroids (AAS) were first used by athletes involved in pursuits of strength, young men interested in enhancing their appearance. There is a scarcity in studies that investigated long term effect of anabolic steroids on skeletal muscles.
Objectives: The current study elucidates morphometric and histological changes of the gastrocnemius (GAS) muscle of albino rats injected by supratheraputic dose of nandrolone and investigate the possible reversibility of these changes after drug stoppage.
Material and Methods: Rats were classified into 3 groups; group I (control group, 20 rats) received no treatments with 2 subgroups A and B: I A to be sacrificed after 8 weeks and I B to be sacrificed after 16 weeks. Group II (treated, 10 rats) received nandrolone by intramuscular injection of 10 mg/kg body weight twice weekly for 8 weeks. III (recovery group, 10 rats) received the same dose of nandrolone for 8 weeks and then sacrificed 8-weeks after stoppage of treatment. The GAS muscle was removed, inspected, weighed and processed for light and electron microscopic examinations, and evaluation of apoptosis by caspase- 3 immunohistochemistry.
Results: GAS muscle of the treated group II exhibit hypertrophy, fibrosis and apoptosis. Muscle fibers present sarcoplasmic degeneration. Dislocation of myonuclei is a conspicuous finding, they appear bizarre and clustering. Activation of satellite cells is presumed by nuclear lobulation and chromatin clumbings in preparation of cellular proliferation. Satellite cells detach from their positon toward the dislocated damaged myonuclei as a step leading to regeneration. Group III shows signs of regeneration in the form of decrease collagen fibers and decrease apoptosis.
Conclusion: There are signs of incomplete recovery skeletal muscles of group III after 8-week stoppage of AAS abuse. Dislocation and internalization of myonuclei and satellite cell proliferation and migration could be considered signs of regeneration after stoppage of the insulting drug.