Influence of sling material on inflammation and collagen deposit in an animal model.

Aim: Compare inflammation and collagen production induced by four sling materials in female rats.

Methods: Adult female rats (n=144) were submitted to a urinary incontinence model and neutering. After four weeks they were randomized in 5 groups: Sham; autologous sling; Marlex; swine intestinal submucosa (SIS), and polypropylene mesh (TVT). Animals were killed at 7, 30 and 90 days. The inflammatory infiltrated area was rated from 0 to 3 (0=area smaller than 25%, 1=between 25% and 50%, 2 between 50% and 75%, and 3 for areas greater than 75%). The presence of granuloma and necrosis was noted. Penetration in the vesical wall was evaluated employing a system of scores from 0 to 3. The amount of collagen I and III, and the total was assessed using the Picro-Sirius staining technique.

Results: The Sham group presented lower inflammatory parameters at 7 days. On the 30th day, the autologous fascia presented inflammatory reactions similar to the Sham group, and lower than the remaining groups. The synthetic materials demonstrated greater inflammatory reactions at 60 days. No differences between groups were observed other than those concerning collagen production, except at 60 days, when TVT and SIS differed from Fascia and Sham in the production of collagen III.

Conclusion: Autologous fascia produced less inflammatory reaction and collagen. TVT and Marlex caused more intense and longer-lasting inflammatory reaction with greater visceral penetration. When TVT was used, this process resulted in a higher quantity of collagen III. The presence of SIS, although presenting a less intense inflammatory reaction than the synthetics, also caused greater collagen III production at 60 days.