Evaluation of Nandrolone Decanoate Effects on Sinoatrial Node in Experimental Rat Model (Histological and Immunohistochemical study)

Background: Nandrolone decanoate (NA) is one of the anabolic steroids used medically and abused by athletes but hasseveral harmful effects.Aim: Evaluate the effect of nandrolone decanoate on sinoatrial node structure of albino rat and the effect of its withdrawal.Materials and Methods: Thirty adult albino rats were divided into three groups each containing ten rats. Group I (control): tenrats were divided into the negative control was left untreated and the positive control was injected by castor oil, twice weekly/8weeks. Group II (NA group): ten rats were injected by NA 5 mg/kg twice/week/8 weeks. Group III (recovery group): ten ratswere injected by NA 5 mg/kg twice/week /8 weeks, then were left 12 weeks to evaluate recovery. At the end, the sinoatrial nodewere dissected out, and subjected to histological and immunohistochemical examination.Results: Examination of right atrial sections of NA injected group showed wide separation of sinoatrial node structure anddisordered cell arrangement. P cell degeneration with increased cytoplasmic vacuoles was noted. Some cardiomyocytesexhibited degenerative changes including wavy sarcoplasm and fragmented pyknotic nuclei. After discontinuation of NA, thesinoatraial node did not regain its normal architecture. Mean area percentage % of collagen fiber deposition, SYN and iNOSimmunoexpressing in NA injected group was significantly increased relative to control group which did not recovered afterdrug withdrawal.Conclusion: Use of NA caused serious changes in sinoatrial node tissue which will threaten life of their users especially theathletes. Thus, NA must be administered only under medical supervision.