Experimental study comparing meshes made of polypropylene, polypropylene + polyglactin and polypropylene + titanium: inflammatory cytokines, histological changes and morphometric analysis of collagen

Abstract

Purpose: Incisional hernia occurs in approximately 11% of all laparotomies. Changes in collagen have been closely implicated in its pathogenesis. The high recurrence rate (45-54%) after primary suture has stimulated the development of meshes. Currently, meshes are the biomaterials implant group most used in medicine. This study aims to compare the serum and tissue inflammatory responses and collagen deposition caused by meshes made of polypropylene, polypropylene + polyglactin and polypropylene + titanium.

Methods: Thirty Wistar rats were divided into three groups. In group I, a high-density polypropylene mesh was positioned on the abdominal wall. In groups II and III, low-density meshes were used in associations with polyglactin and titanium, respectively. Immediately before the operation and on the first, third and fortieth postoperative days, pro-inflammatory cytokines were assayed. On the 40th postoperative day, the region of the inserted prosthesis was biopsied. The tissue inflammatory reaction was evaluated using a scale for objective scoring. For collagen, picrosirius was used with data reading using the Image Tool computer software.

Results: Cytokines: there were no statistically significant differences between the groups.

Histology: on the 40th postoperative day in group I, there were fewer inflammatory tissue response and greater collagen deposition (P < 0.01). In group II, there were greater inflammatory tissue response and less collagen deposition (P < 0.01). Group III presented intermediate values between groups I and II.

Conclusions: There were no significant differences in cytokine levels between the groups in the present study. In the animals with the polypropylene + polyglactin mesh implant there was the most intense inflammatory process with lower tissue maturation and collagen deposition on the 40th postoperative day. The polypropylene mesh presented a less severe late inflammatory process, with greater tissue maturation and collagen deposition. The polypropylene + titanium mesh presented intermediate values between the others.