Tissue reaction to urogynecologic meshes: effect of steroid soaking in two different mesh models

Steroid soaking may decrease mesh-triggered inflammatory reaction in tissue. We aimed to investigate the tissue reaction to a steroid-soaked mesh material and an unsoaked mesh material in the rat model.

Neutral and steroid-soaked type I macroporous polypropylene (PP) monofilament and polyvinylidene fluoride (PVF) mesh materials were implanted on the rectus abdominis muscle of 20 mature Wistar albino rats. Animals were divided into four groups: PP mesh with steroid (PP-S), PP mesh without steroid, PVF mesh with steroid (PVF-S), and PVF mesh without steroid. The rats were killed after 12 weeks, and histologic, immunohistochemical and electron microscopic examinations were performed. For immunohistochemical analysis, polyclonal rabbit anti-mouse CD3, rabbit anti-mouse CD68, rabbit anti-mouse CD15, and rabbit anti-mouse CD34 antibodies were used for the detection of lymphocytes, macrophages, polymorphonuclear leukocyte foreign body giant cells, and fibromyocyte stem cells, respectively. Samples were stained with hematoxylin and eosin for the histologic evaluation of inflammation and with Masson's trichrome stain for the evaluation of collagen deposition. Pore size and mesh ultrastructure were evaluated by electron microscopy.

Expression of CD3 was lower in the PVF, PVF-S and PP-S groups, and expression of CD34 was higher in the PVF-S and PP-S groups than in the PP groups (p < 0.05). Collagen deposition was lower in the PVF, PVF-S and PP-S groups (p < 0.05). Histologically, the intensity of inflammation was lower in the PVF-S and PP-S groups than in the PP mesh group (p < 0.05). There were no significant differences among the groups in terms of pore size and mesh ultrastructure on electron microscopic examination (p > 0.05).

PVF mesh induces less inflammation than PP mesh, and in both mesh types steroid soaking further decreases inflammation without changing the pore size.