Intra-prostatic injection of botulinum toxin type A in treatment of dogs with spontaneous benign prostatic hyperplasia

Benign prostatic hyperplasia (BPH) is a common, naturally developing, age-related condition in dogs. The pathogenesis of BPH is not completely known; however, DHT is a hormone involved in enlargement of the prostate. Recently, the effect of botulinum toxin A (BT-A) was investigated in the rat and human prostate and has shown to induce atrophy of the gland on the canine prostate. This study investigated the effect of BT-A in the canine prostate and on the semen. Eight sexually intact male dogs with BPH (detected radiographically and ultrasonographically), and with clinical signs of BPH (e.g. hematuria or tenesmus) were used. Each lobe of the prostate received an injection of 125U of BT-A with one-needle pass under transabdominal ultrasound guidance. The clinical results were evaluated at baseline and after treatment. No local complications or systemic adverse effects were reported. At 4weeks, the mean prostate volume (PV) was not significantly changed after BT-A (from 17.70±6.34 to 16.48±5.98cm(3)). At 8 weeks the PV had further decreased to 16.04±5.80cm(3), reaching its maximum effect, but that change was not significant. The results were maintained at 16 weeks. All dogs had normal libido, erection, and ejaculation during semen collection. No significant difference was observed in all seminal parameters. Results suggest that the administration of 250U of BT-A do not contribute to PV reduction and do not adversely affect the semen quality of dogs with BPH.