Comparison of polypropylene mesh and porcine-derived, cross-linked urinary bladder matrix materials implanted in the rabbit vagina and abdomen

Abstract

Our aim was to compare histological and biomechanical effects of polypropylene (PP) mesh and porcine-derived, cross-linked urinary bladder matrix (cUBM) graft materials using a rabbit vaginal and abdominal model. Forty rabbits were implanted with PP mesh (n = 20) or cUBM (n = 20) in the vagina and abdomen. Two grafts (PP or cUBM) of the same type were placed into each site, so each rabbit had four grafts. Grafts were harvested 12 weeks later and processed for histologic analysis and biomechanical testing. There were high rates of two types of grafts missing in the vagina. Vaginal PP was associated with erosion reaction (67%), whereas abdominal PP and cUBM showed no sign of erosion. All patches adhered to rectus abdominis or vaginal mucosa and shrank to varying degrees, especially for PP grafts. Compared with vaginal PP, vaginal cUBM induced milder chronic inflammation response, had lower scores (P = 0.000) for inflammation response, and showed higher scores for neovascularization (P = 0.000) and fibroblastic proliferation (P = 0.002). In the abdomen, both histopathological parameters were insignificantly different (P > 0.05) between cUBM and PP. The mechanical properties of UBM did not deteriorate following implantation, whereas the ultimate tensile strength and elastic modulus of vaginal PP increased. PP had higher scores for tensile and break strength than did cUBM (P < 0.05). The cUBM has good biocompatibility, high ability to integrate with the vagina, and maintains mechanical properties in vivo. It may be a promising material for pelvic floor reconstruction.