Decreased Uncoupling Protein 2 and 3 (UCP2 and UCP3) mRNA expression by endurance exercise training with and without chronic administration of nandrolone in rat heart

Introduction: The effect of regular exercise in decreasing the incidence of heart diseases is well known. The abuse of anabolic androgenic steroids (AAS) has been associated with cardiovascular disorders. Uncoupling proteins (UCPs) transport protons across the inner mitochondrial membrane; thereby proton gradient can be diminished by the action of UCPs. This process will result in the uncoupling of mitochondrial respiration from ATP production. The goal of this study was to investigate whether UCP2 and UCP3 are involved in the mechanisms of AAS-induced cardiac damage in the rat heart. Methods: In the current study, adult male Wistar rats were divided into five groups (n=8): Control, vehicle, nandrolone, exercise, exercise-nandrolone. Rats in the exercise groups were submitted to a progressive running program on a treadmill, 5 days a week for 10 weeks. Rats in the nandrolone and exercise-nandrolone groups received a weekly intramuscular injection of nandrolone decanoate (10 mg/kg), while those in the vehicle group received Arachiz oil as vehicle. Relative mRNA expression of UCP2 and UCP3 were determined with real-time RT-PCR. Results: The data showed that chronic administration of nandrolone significantly up-regulated UCP2 and UCP3 mRNA in rat heart and endurance training induced a decrease in the expression of UCP2 and UCP3 mRNA with or without presence of nandrolone. Conclusion: It may be concluded that chronic nandrolone treatment causes an increase in the expression of UCP2 and UCP3 mRNA. Thus, it might decrease energy metabolism efficiency by impairment of ATP production. Physical activity may decrease the adverse effects of nandrolone by down-regulation of the UCP2 and UCP3 mRNA expression.