The rabbit as an animal model for proctology research: anatomical and histological description.

PURPOSE: This study was designed to describe the surgical anatomy and histology of the rabbit anorectum comparing it to that of humans, in order to decide whether it can be a good experimental model for research in proctology.

MATERIAL AND

METHODS

This study of the anorectal region was performed on six female New Zealand white rabbits, weighting between 2.5-2.9 kg. An autopsy was performed immediately after sacrificing the animal and an anatomical and histological description was performed.

RESULTS

The mean rectum and anal canal lengths were of 7.2 cm and 0.9 cm, respectively. The macroscopic study showed that the musculature of the anal canal is formed by the coccygeus muscle, which serves as puborectalis in humans. It also defined an external anal sphincter with a deep and superficial portion. The histological evaluation showed similarity to that of humans, with mucosa of simple columnar type, muscularis mucosae, a small submucosa, with a muscular wall divided into internal and external layers, separated by the myenteric plexus.

CONCLUSION

The great similarity to both the anatomy and the histology of humans, appropriate size and easy-handling and care, make the rabbit an attractive animal for the use as experimental and research model in proctology.