NON-INVASIVE SAMPLING METHODS FOR GENOTYPING: IMPROVEMENTS TOWARDS THE 4R PRINCIPLE

2025-04-01T11:45:52+00:00

Genetically modified mice are usually genotyped using invasive ear or tail biopsies. In accordance with the 4R principle (Replacement, Reduction, Refinement and Responsibility) we have developed non-invasive sampling methods to prevent stress and pain for mice. DNA could be extracted from oral swabs and hair follicles using conventional PCR and real-time PCR. Signals could be detected up to 25 days after sampling, if the swabs were shipped and stored at +4°C. In a pilot study, oral swabs, hair and biopsies were compared, showing consistent genotyping results in all three sampling methods with hair being more susceptible to contamination. Oral swab and hair follicle sampling provide an alternative that can be used for large-scale routine genotyping, especially if no invasive biopsy is allowed (e.g., animals with ear tags or toe tattoos) or no second biopsy is possible.

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

2025-06-23T10:23:28+00:00

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.

Scandinavian Journal of Laboratory Animal Science

NON-INVASIVE SAMPLING METHODS FOR GENOTYPING: IMPROVEMENTS TOWARDS THE 4R PRINCIPLE

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