Histological Study on the Effect of Nandrolone on the Structure of Skeletal Muscle of Adult Male Albino Rat Subjected to Physical Exercise

Abstract

Androgenic anabolic steroids as nandrolone decanoate were first introduced in minimal doses for therapeutic purposes. However, athletes began to abuse these drugs in high supra-physiological doses to make benefit from their anabolic nature. Studies were done to warn against the side effects that might result from abusing these drugs at such high doses. It was proved that these drugs could lead to various serious adverse effects. They may even alter the physiological and psychological state of the user. All of these precious data could not stop those athletes from abusing these drugs. New studies discussed the effect of these drugs on the musculoskeletal system. Physical exercise was introduced in various studies to determine its effect on the skeletal muscles in comparison to these drugs. In the present study forty-two adult male albino rats of average weight 150 – 200 gms were used. They were classified into five main groups: Group I (Control group): Fourteen rats were used which were further subdivided into two equal subgroups. Subgroup Ia served as a negative control group. Subgroup Ib, the rats were injected with an equivalent volume of the vehicle (Arachis oil: alcohol 90:10) twice weekly for six weeks. Group II (Steroid only group): Seven rats were injected intramuscularly with nandrolone (Nandurabolin, 25 mg/ml) in a dose of 5 mg/kg twice weekly for six weeks in the right gastrocnemius muscle. Group III (Training only group): Seven rats performed a training program for six weeks. They were allowed to swim in a container for five days a week. The period of swimming was increased gradually from 10 minutes on the first day of the first week till 90 minutes in the last day of the training program. Group IV (Steroid and Training group): Seven rats were injected with the steroid as in group II, they were also allowed to perform the training program as in group III. Group V (Recovery form steroid and training group): Seven rats were treated as in group IV, they were left to recover for four weeks. At the end of the experiment, the right gastrocnemius muscles of all rats were dissected out and subjected to light and electron microscopic studies. Morphometric measurements and statistical analysis for the surface area of the muscle fibers, number of myonuclei and the area percentage of collagen were also performed. Paraffin sections were stained by heamatoxyline and eosin, Masson's trichrome stain and PAS stain. At the end of the present study, there was a significant increase in the body weight of rats of the experimental groups as compared to that of control rats. The maximum body weight was recorded in rats of group II, the steroid group. The mean weight of each rat reached about 310 gms. H&E stained sections of rats of both groups II and IV showed distorted muscle fibers. Multiple spaces were detected between the myofibrils with loss of their cross striation. They appeared with angulated sarcolemma. Mononuclear cellular infiltration and congestion of the dilated blood vessels were also detected. These findings were more obvious in animals of group II. Most of the muscle fibers of rats of the training group had a similar structure to that seen in control sections. Increase in the diameter of some muscle fibers was observed. Minute spaces were seen in other fibers. In recovery group most of the muscle fibers had a histological picture as that seen in control rats. Some fibers contained multiple oval nuclei under their sarcolemma. There was a significant decrease in the surface area of the muscle fibers of rats of group II as compared to control rats. A significant increase in the surface area was also detected in rats of group III (training group) as compared to control rats. Non-significant changes in the surface area were seen in rats of both groups IV and V as compared to control rats.