Different local responses of rat connective tissue to PTFE and PP surgical meshes implanted in the body

<p>Objective: As of 2021, a polytetrafluoroethylene (PTFE) mesh product and 2 polypropylene (PP) mesh products are used in pelvic floor repair surgeries in Japan. The present experiment was planned to compare the local reactions caused by implantation of these meshes.</p><p>Materials and methods: Three types of mesh pieces were implanted in contact with the temporal muscle ligament of six 13-week-old female Slc:SD rats, and the animals were kept for 2 weeks before the tissues were removed to prepare pathological specimens. An observer who was not informed of the specimen details performed an optical microscope evaluation for the selected nine endpoints concerning the response of inflammatory cells and connective tissue.</p><p>Results: When collecting specimens, the PTFE mesh could be easily separated from the surrounding tissue, while the PP meshes were firmly adhered. The score of PTFE mesh was significantly lower than that of PP mesh in three out of five endpoints assessing the response of inflammatory cells (Mann-Whitney's U test, p-value < 0.05). Two of the four endpoints assessing inflammation-induced connective tissue changes were positive only in the PP mesh. Overall, PTFE meshes scored lower than PP meshes in seven of the nine endpoints. Conclusion: When implanted in a site exposed to mechanical stress, the local response of rats to PTFE mesh is lighter and milder than that of PP mesh. In humans, the use of PTFE mesh for pelvic floor reconstructive surgery may reduce the strong scarring and mesh exposure that have been experienced with PP mesh.</p>