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Yale University School of Medicine, Department of Orthopaedics and Rehabilitation, New Haven, Connecticut 06520-8071, USA.
The effect of an anabolic steroid (nandrolone decanoate, 20 mg/kg) and a corticosteroid (methylprednisolone acetate, 25 mg/kg) on healing muscle injured with a drop-mass technique in a reproducible muscle contusion injury model in the rat was studied. Healing was determined by measuring active contractile tension in each muscle and histologic analysis. At day 2, the corticosteroid group showed significant improvement in both twitch and tetanic strength relative to the controls. At day 7, this effect was reversed and the corticosteroid muscles were significantly weaker than the control muscles, but there was still no significant effect seen in the anabolic steroid group. At day 14, the corticosteroid muscles were totally degenerated, with disorganized muscle fiber architecture. The anabolic steroid muscles were significantly stronger in twitch, and a similar trend was seen in tetanus relative to control muscles. The results indicate that in an animal model corticosteroids may be beneficial in the short term, but they cause irreversible damage to healing muscle in the long term, including disordered fiber structure and a marked diminution in force-generating capacity. Anabolic steroids may aid in the healing of muscle contusion injury to speed the recovery of force-generating capacity. Although anabolic steroids are considered renegade drugs, they may have an ethical clinical application to aid healing in severe muscle contusion injury, and their use in the treatment of muscle injuries warrants further research.
General Physiology Laboratory, CNRS E.P.1593, Faculty of Sciences and Technology, University of Nantes, 44322 Nantes, France. [email protected]
PURPOSE: We studied the effects of high doses of an anabolic-androgenic steroid, exercise training, and a combination of steroid and training on mammalian fast- and slow-twitch skeletal muscles at the cellular level. METHODS: Thirty-two male rats were divided into sedentary and treadmill-trained groups (increased speed and time: 18 m.min-1, 0.5 h.d-1, 5 d.wk-1). Eight animals of each group were treated with nandrolone decanoate (ND) (15 mg.kg-1.wk-1), and others received the same doses of solvent. The animals were killed after 5 wk, and the contractile parameters for isolated small bundles of soleus and extensor digitorum longus (edl) fibers were estimated. Results: Muscle mass, twitches, and K+ contractures were increased in soleus and edl muscles after the drug treatment and after the exercise training. Caffeine contractures were increased only after the exercise training. The combination of exercise with ND treatment produced greater effects, particularly a significant increase in sensitivity to caffeine and the amplitude of K+ contractures as well as a shortening of the time required to restore contracture. These modifications were more marked in slow than fast muscle. Conclusion: These results show that 5 wk of exercise training produced changes in the contractile responses developed by isolated skeletal muscle cells. The combination of exercise training with ND treatment potentiated these effects, suggesting that there was some modification in the excitation-contraction coupling mechanism. ND treatment also produced a more potent effect in soleus than edl sedentary muscle.
The effect of an anabolic steroid (nandrolone decanoate, 20 mg/kg) and a corticosteroid (methylprednisolone acetate, 25 mg/kg) on healing muscle injured with a drop-mass technique in a reproducible muscle contusion injury model in the rat was studied. Healing was determined by measuring active contractile tension in each muscle and histologic analysis. At day 2, the corticosteroid group showed significant improvement in both twitch and tetanic strength relative to the controls. At day 7, this effect was reversed and the corticosteroid muscles were significantly weaker than the control muscles, but there was still no significant effect seen in the anabolic steroid group. At day 14, the corticosteroid muscles were totally degenerated, with disorganized muscle fiber architecture. The anabolic steroid muscles were significantly stronger in twitch, and a similar trend was seen in tetanus relative to control muscles. The results indicate that in an animal model corticosteroids may be beneficial in the short term, but they cause irreversible damage to healing muscle in the long term, including disordered fiber structure and a marked diminution in force-generating capacity. Anabolic steroids may aid in the healing of muscle contusion injury to speed the recovery of force-generating capacity. Although anabolic steroids are considered renegade drugs, they may have an ethical clinical application to aid healing in severe muscle contusion injury, and their use in the treatment of muscle injuries warrants further research.
General Physiology Laboratory, CNRS E.P.1593, Faculty of Sciences and Technology, University of Nantes, 44322 Nantes, France. [email protected]
PURPOSE: We studied the effects of high doses of an anabolic-androgenic steroid, exercise training, and a combination of steroid and training on mammalian fast- and slow-twitch skeletal muscles at the cellular level. METHODS: Thirty-two male rats were divided into sedentary and treadmill-trained groups (increased speed and time: 18 m.min-1, 0.5 h.d-1, 5 d.wk-1). Eight animals of each group were treated with nandrolone decanoate (ND) (15 mg.kg-1.wk-1), and others received the same doses of solvent. The animals were killed after 5 wk, and the contractile parameters for isolated small bundles of soleus and extensor digitorum longus (edl) fibers were estimated. Results: Muscle mass, twitches, and K+ contractures were increased in soleus and edl muscles after the drug treatment and after the exercise training. Caffeine contractures were increased only after the exercise training. The combination of exercise with ND treatment produced greater effects, particularly a significant increase in sensitivity to caffeine and the amplitude of K+ contractures as well as a shortening of the time required to restore contracture. These modifications were more marked in slow than fast muscle. Conclusion: These results show that 5 wk of exercise training produced changes in the contractile responses developed by isolated skeletal muscle cells. The combination of exercise training with ND treatment potentiated these effects, suggesting that there was some modification in the excitation-contraction coupling mechanism. ND treatment also produced a more potent effect in soleus than edl sedentary muscle.
