Background: Nandrolone decanoate (NA) is one of the anabolic steroids used medically and abused by athletes but has
several 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): ten
rats were divided into the negative control was left untreated and the positive control was injected by castor oil, twice weekly/8
weeks. Group II (NA group): ten rats were injected by NA 5 mg/kg twice/week/8 weeks. Group III (recovery group): ten rats
were injected by NA 5 mg/kg twice/week /8 weeks, then were left 12 weeks to evaluate recovery. At the end, the sinoatrial node
were 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 and
disordered cell arrangement. P cell degeneration with increased cytoplasmic vacuoles was noted. Some cardiomyocytes
exhibited degenerative changes including wavy sarcoplasm and fragmented pyknotic nuclei. After discontinuation of NA, the
sinoatraial node did not regain its normal architecture. Mean area percentage % of collagen fiber deposition, SYN and iNOS
immunoexpressing in NA injected group was significantly increased relative to control group which did not recovered after
drug withdrawal.
Conclusion: Use of NA caused serious changes in sinoatrial node tissue which will threaten life of their users especially the
athletes. Thus, NA must be administered only under medical supervision.