Immunochemical analysis on polypropylene mesh: does mesh size make a difference?

ABSTRACT

INTRODUCTION AND HYPOTHESIS: The aim of the study is to demonstrate the impact of the size of implanted mesh in relation to its immunohistochemical reaction implanted into animal models. METHODS: An experimental study utilizing 54 female Sprague Dawley (SD) rats was divided into five groups control, sham, and study groups (mesh-small [M-S], mesh-medium [M-M], mesh-large [M-L]). The M-S group used a mesh size of 0.2 × 0.2 cm, the M-M group a mesh size of 0.5 × 0.5 cm, and the M-L a mesh size of 0.7 × 1.0 cm. The sham group underwent vaginal dissection with no mesh implantation. The rats were sacrificed using isoflurane overdose on days 7 and 30. The mesh with the surrounding vaginal and bladder wall tissues were removed and processed for histochemical and western blot analysis. RESULTS: There is a significant increase in IL-1 and TNF-α immunoreactivity in the M-M and M-L groups on day 7 when compared with the sham group with p values of 0.001 and < 0.001 respectively. M-L showed significantly higher immunoreactivity to TNF-α persisting until day 30. All study groups presented a significantly higher immunoreactivity to MMP-2 and NGF on day 7. However, reactivity to NGF does not persist to day 30 in all groups. Immunoreactivity to CD 31 on days 7 and 30 appears significantly greater in the M-M and M-L groups, with the reaction in the M-L group continuing until day 30. CONCLUSION: Mesh size is directly proportional to the inflammatory reaction in the host tissue. The prolonged inflammatory process leads to delayed tissue remodeling and angiogenesis, which could delay mesh-tissue integration.