Feasibility of the New Zealand white Rabbit as an Animal Model for the Study of Biological Grafts in the Pelvic Floor Dysfunctions

Abstract

Objective: to investigate the feasibility of the New Zealand White (NZW) rabbit to study human acellular dermal matrix (hADM) biomaterials in pelvic reconstructive surgery. Study design: 20 white female NZW rabbits were randomized into 2 groups, the experimental group (hADM graft) and the control group (Polypropylene graft; PP). In each animal, grafts were surgically implanted subcutaneously in the abdominal wall and in the vaginal submucosa layer for 180 days. The graft segments were then removed and the surgical and clinical results were analysed. Results: The main surgical challenges were: a) to obtain the adequate vaginal exposure and the maintenance of the integrity of the vaginal mucosa layer; b) to keep aseptic conditions; c) to locate and dissect the breast vein during abdominal surgery; and, d) to withdraw blood samples from the ear artery. The most abnormal findings during the explant surgery were found in the PP group (33% of vaginal mesh extrusion) in comparison with the hADM group (0% of vaginal graft extrusion), p=0.015. Interestingly, macroscopic observation indicated that the integration of the vaginal grafts was more common in the hADM group (40%) than in the PP group, in which the vaginal mesh was identified in 100% of the animals (p=0.014). Conclusions: The NZW rabbit is an excellent model to assess materials to be used as grafts for pelvic reconstructive surgery and vaginal surgery. Animals are easily managed during the procedures, including the surgical intervention and vaginal mucosa handling.