Pelvic meshes must be firmly anchored to surrounding tissues and withstand repetitive shear stress. Efficient preclinical evaluation is therefore essential for the development of novel pelvic mesh materials [1,2]. With pelvic mesh development in mind, we aimed to establish a rat buccal implantation model in which a small mesh fragment is positioned along the temporalis muscle, creating an environment where shear stress is continuously applied to both surfaces of the mesh, and to observe healing and postoperative recovery under these conditions.

This study was conceived by the presenter and conducted by a facility specializing in contracted laboratory animal experiments. Twenty-one female Sprague–Dawley rats (13 weeks old) were maintained in a standard barrier environment throughout the pre- and postoperative periods.
Under general anesthesia and sterile conditions, a skin incision about 2 cm long  was made over the temporalis muscle midway between the orbit and the auricle. The buccinator muscle was incised to expose the temporalis muscle. Three Amid Classification type I mesh materials—polypropylene (PP), polytetrafluoroethylene (PTFE), and polyvinylidene fluoride (PVDF)—were cut into approximately 1-cm square patches with a 2.5-mm-wide handle. Each patch was placed against the muscle, and the handle was wrapped around the temporalis muscle ligament for fixation, followed by wound closure [3].
To monitor postoperative health status, feeding behavior was captured on video weekly, and body weight was measured weekly; body weight changes were analyzed using paired t-tests (significance level p < 0.05). For histopathologic evaluation of host responses around the implanted mesh, buccal region specimens were harvested at 4, 12, and 24 weeks post-implantation, fixed in formalin, and stained with hematoxylin and eosin, Masson’s trichrome, and Gram stains. All specimens were examined under blinded conditions by experienced evaluators.

All rats survived and remained healthy. Body weight showed no consistent change during the first postoperative week, but increased by 4.92 ± 0.72% at 2 weeks and by 11.21 ± 0.97% at 4 weeks postoperatively (p < 0.001). Video observation of feeding showed active intake of food and water by postoperative day 6, suggesting that shear stress was applied to the implanted mesh during mastication.
In all specimens, the implanted mesh showed no wrinkling or twisting. The mesh was stabilized by tissue ingrowth and surrounded by mild-to-moderate foreign-body granulomas. At 4 and 12 weeks, granuloma formation was mild and comparable between PTFE and PP. At 24 weeks, host reactions were more pronounced in PP than in PTFE, with increased foreign-body giant cells, macrophages, lymphocytes, and neutrophils. With the exception of one animal in which an abscess was identified In contact with the mesh, no bacterial persistence was observed. Within the observed range, fibrosis was mild and comparable between PTFE and PP.

Buccal implantation of mesh in rats was a relatively simple surgical procedure, and animals recovered stably postoperatively without mesh displacement or deformation. Because many animals could be maintained with relatively low cost and labor, this model allowed larger sample sizes. Whether the anticipated shear stress was acting at the implantation site could be confirmed macroscopically by observing video footage of feeding behavior. In addition, evaluation of perimesh tissue responses can be further expanded by incorporating image-based analyses using specialized histological staining and biochemical assays that were not performed in the present study.

The rat buccal model may be useful for preclinical studies of pelvic mesh materials, including absorbable materials, and merits further validation.

Seifalian, A., Digesu, A. & Khullar, V. The use of animal models in preclinical investigations for the development of a surgical mesh for pelvic organ prolapse. Int Urogynecol J 35, 741–758 (2024).
Boris Arts. Applications of electrospun scaffolds: Using a supramolecular approach to improve material tissue interactions. (Doctoral thesis, Eindhoven University of Technology, 2025).
1. Fujisawa, M. et al. A novel experimental model to verify the safety and local reactivity of surgical mesh. Translational and Regulatory Sciences 7, 112–119 (2025).