Tissue Reaction of the Rat Urinary Bladder to Synthetic Mesh Materials

The aim of this study was to assess urinary bladder histopathology induced by the sling materials tension-free vaginal tape (TVT), vypro mesh, and intravaginal slingplasty (IVS). Thirty rats were studied: sham-operated controls, TVT, vypro, and IVS groups. After laparotomy, a 0.5- x 1-cm piece of mesh was implanted on the anterior bladder wall. The bladder was examined histopathologically after 12 weeks. Inflammation, foreign-body reaction, subserosal fibrosis, necrosis, and collagen deposition were graded. The Kruskal-Wallis and posthoc Dunn tests were used. The sham-operated rats showed no tissue reactions. The TVT, vypro, and IVS groups showed increased inflammation (p = 0.006, p = 0.031, p = 0.001), subserosal fibrosis (p = 0.0001), foreign-body reaction (p = 0.0001), and collagen deposition (p = 0.0001) as compared to sham. Inflammation was more intense in the IVS group as compared to the TVT and vypro groups (p = 0.041, p = 0.028). The bladder presented more increased inflammatory response to IVS than the other meshs. This may play a role in the ultimate outcomes or complications from slings.