The impact of steroid-impregnated polypropylene mesh on foreign body reaction in an experimental rat study

Foreign body reaction is a tissue response in which excessive reactions may lead to complications such as chronic inflammation, mesh contraction, and impaired tissue integration. The present study aimed to evaluate the effects of steroid-impregnated polypropylene mesh on foreign body reaction and fibrosis in a rat abdominal wall model.

Forty adults female Wistar rats were randomly assigned into four groups (n = 10 each): polypropylene mesh in the acute period (group A), steroid-impregnated polypropylene mesh in the acute period (group AS), polypropylene mesh in the chronic period (group C), and steroid-impregnated polypropylene mesh in the chronic period (group CS). Standardized 1 × 1-cm meshes were implanted on the right rectus abdominis muscle. Acute groups were assessed at three days post-implantation, and chronic groups at nine weeks. Histopathological evaluation included grading of polymorphonuclear leukocyte infiltration, neovascularization, foreign-body giant cell reaction, muscle invasion, necrosis, and fibrosis. Immunohistochemical staining for CD15, CD68, CD3, and CD20 was performed to characterize inflammatory cell subtypes.

The mean grading of polymorphonuclear leukocyte infiltration, neovascularization, foreign-body reaction, muscle invasion, and necrosis showed no difference among groups, in which fibrosis levels were significantly higher in group C and group CS compared to group A (p = 0.004, p = 0.004, respectively). The fibrosis levels were also elevated in group CS than in group AS (p = 0.001, p = 0.001, respectively).

Local corticosteroid impregnation of polypropylene mesh slightly attenuated early inflammatory responses but did not prevent chronic fibrosis.