Hormone and prostate changes in dogs with BPH treated by finasteride

Abstract

Benign prostatic hyperplasia (BPH) is a disorder related to hormone imbalance, local angiogenesis, and prostate growth, which can be treated surgically (orchiectomy) or medically (most commonly with finasteride). However, finasteride therapy is not completely established in dogs regarding local action and posology. This study aimed to evaluate the effect of different doses of finasteride and orchiectomy on hormonal profile, prostate apoptosis, blood flow, and biometry in dogs with BPH. Dogs were assigned to the following groups: untreated, 0.1 mg, 0.2 mg, and 0.5 mg/kg/d of finasteride and orchiectomy. All dogs were assessed monthly: day 0 (before treatment), day 30, and day 60 and subjected to prostate B-mode and Doppler ultrasonography and hormonal analysis (testosterone and dihydrotestosterone). After 60 d, prostatic biopsy was performed for histology and immunohistochemical evaluation for apoptosis (caspase-3). On day 60, percentage reduction of prostatic volume was greater in orchiectomized dogs than that in finasteride groups, which, conversely, was greater than untreated dogs. On day 60, 0.2-mg finasteride, 0.5-mg finasteride, and orchiectomy groups had higher prostatic blood flow than 0.1-mg finasteride and untreated groups. In addition, both 0.5-mg finasteride and orchiectomy groups had an increase in prostate artery resistance. Orchiectomy significantly decreased androgen concentrations at 30 d onward, differing from the remaining groups. The orchiectomy group had lower caspase-3 immunostaining, however, not different from untreated and 0.5-mg finasteride. In conclusion, 0.5 mg/kg finasteride promoted more effective prostate apoptosis and hemodynamic effects among medical treatments, whereas orchiectomy caused prostate atrophy and sharp endocrine changes in dogs with BPH.