Peritoneal adhesion formation and reformation tracked by sequential laparoscopy: optimizing the time point for adhesiolysis.

BACKGROUND: In a high proportion of patients, operatively lysed adhesions reform. Using a rabbit adhesiogenesis model, this study assessed the efficacy of adhesiolysis and examined how this relates to the tissue composition of adhesions at the time of lysis.

METHODS: Polypropylene meshes (5 x 3.5 cm) were implanted on the parietal peritoneum of New Zealand white rabbits. Some animals were killed 3, 7, 14, and 90 days postimplantation to obtain adhesion tissue. Adhesion formation/reformation was monitored by sequential laparoscopy in other animals kept for 90 days and in a separate experimental group subjected to adhesiolysis at 3 days postimplantation. Immune and inflammatory response markers were determined by immunohistochemical, Western blotting, and real-time reverse transcriptase polymerase chain reaction procedures in adhesion tissue; areas occupied by adhesions were quantified in meshes.

RESULTS: In animals undergoing adhesiolysis, mesh areas covered by adhesions were significantly decreased at each follow-up time and affected areas became mesothelialized. Increased transforming growth factor (TGF)-beta1 expression was detected in adhesions at 3 days. Greatest TGF-beta1 and vascular endothelial growth factor (VEGF) protein expressions were observed at 7 days, whereas genetic overexpression was noted at 14 days. Active inflammatory cells peaked at the 7-day time point.

CONCLUSION: Adhesions formed at 3 days; at this critical time, an adhesiolysis was effective in preventing reformation of future adhesions. TGF-beta1 gene and protein expression were increased in 3-day adhesions with respect to the omentum. Levels of active TGF-beta1 and VEGF were increased at 7 days, along with the inflammatory response at this time point related to tissue remodeling, which led to stabilization of adhesions.