Ablation of canine prostate using two-stage intraprostatic hot agarose solution and enzyme injection

Enzyme ablation of the hyperplastic prostate may be an ideal method of management of BPH. However, the unsatisfactory ablation affects in vivo contrast with successful in vitro results limiting the enthusiasm for further research. In this study, we make efforts to solve the problems in the use of enzyme ablation of BPH in vivo and to measure satisfactory effect.

A total of 18 hybrid dogs between the ages of 7 and 11 y underwent this experiment. Eight dogs were divided into four groups according to the injection formula: enzyme solution, hot D-Hanks' plus enzyme solution, hot agarose plus enzyme solution, and hot agarose solution alone. After selecting the agarose plus enzyme solution group in the first month, the remainder 10 dogs were treated with this two-stage method. Intravenous or oral antibiotics were administered perioperatively. All operations were performed directly by way of laparotomy. The prostates were observed and harvested with surrounding tissue at 24 hrs, 7 days, 14 days, 1 month and 3-5 months after treatment. Gross and microscopic examinations were performed.

Only agarose plus enzyme group shows obvious cavity formation with concomitant size reduction and softening of the prostate ablation effect in the four groups. At 24 h after injection, the prostates demonstrated cavity formation containing liquefied necrotic tissue. The liquefied tissue was absorbed in 7-14 days. At 1 month, the size of most prostates decreased with a corresponding decrease in the size of the cavities. The cavities nearly disappeared within 3-5 months, and the size of prostates decreased to between 1/2 and 1/4 of the pretreatment sizes. All prostates had intact urethral mucosa and capsule. No complications directly related to enzyme ablation were identified. In the control groups there were no significant cavities or decrease in prostate size.

This two-stage thermal and enzyme ablative method can significantly ablate prostate tissue without identifiable complications, and would be possibly applied to treating human BPH in the future.