A Pilot study on the welfare of laboratory rabbits after urethral stricture induction by electrocauterization and open urethrotomy.

Abstract

The study assessed the welfare of rabbits after inducing urethral stricture. This is a pilot study to assess appropriate experimental model before further experiments on the treatment of urethral stricture with artificial tissue.  A review of the literature revealed that electrocauterization, also known as electrocoagulation, is the most reliable method for inducing urethral stricture in rabbits. The results were compared to the simple urethral incision, otherwise known as open urethrotomy. Unfortunately, we experienced that electrocauterization is poorly tolerated by laboratory animals. Weight loss was the most important parameter, indicated the poor health of the rabbit after surgery. In addition, we monitored other parameters such as temperature, fur quality, urination, general behavior, urine and blood samples. No major difference was found between the groups in any other parameter except for weight change. 4 weeks after the operation, the weight of the rabbits in the cauterization group had decreased by 12% compared to their initial weight. Cauterization group animals started to recover at the 5th postoperative week and returned to normal weight by the end of the 12th week. It is proven that postoperative conditions of the laboratory rabbits, like stress, discomfort during urination, pain or postoperative ileus could cause their weight loss. Open urethrotomy was tolerated better, the weight of rabbits in this group did not change notably, but urethral stricture did not develop either. In summary, we can conclude that electrocauterization is a reliable method of inducing urethral stricture, but in order to improve animal welfare, more intense analgesics and anti-inflammatory drugs should be administered. We suggest using an additional pain scale to monitor the welfare of rabbits, and continuing further experiments no earlier than 6-8 weeks after the initial urethral stricture induction, when the health of the rabbits improves.