Transurethral enzymatic ablation of the prostate: Canine model

Objectives. The purpose of this study was to investigate the toxicity and potential usefulness of transurethral prostatic injection of a collagenase-based solution in treating benign prostatic hyperplasia in dogs. Methods. The injected solution contained collagenase, hyaluronidase, Triton X-100, and gentamicin. Twenty-one dogs were randomly divided into three groups for transurethral prostatic needle injection: two treatment groups were observed for 6 and 12 weeks and a control group was observed for 12 weeks. Laboratory studies, clinical monitoring, and complete postmortem examination were performed in all animals. Results. Gross hematuria was noted in all dogs for a mean of 4 days after injection. No significant postoperative morbidity was noted. There were no significant differences in the values of laboratory tests among the three groups except for a mean increase in serum level of aspartate transaminase for treatment groups on postoperative day 1; this resolved by postoperative day 7. Histologically, all treated prostates had stromal atrophy and cystic acinar dilatation involving about 30% of the gland without extraprostatic extension of these changes. The urethra, bladder, rectum, testicles, kidney, liver, and lungs were normal and intact in all animals. Conclusions. Transurethral injection of this enzyme solution creates a predictable, favorable histologic response in the canine prostate. The procedure appears safe and warrants further investigation for treatment of human benign prostatic hyperplasia.