Rats develop more robust and persistent peritoneal adhesion phenotypes than mice: a multimodal comparative study.

This study aimed to compare the differences between rat and mouse models of peritoneal adhesions (PAs). The cecum-abdominal wall ischemic injury suture method was used to establish postoperative PA models in Sprague-Dawley rats and BALB/c mice. Adhesion progression was systematically evaluated via a multimodal system comprising imaging (micro-computed tomography [CT]), macroscopic scoring (Degree of Adhesion and Separation Index [DASI]), and histopathology/immunohistochemistry. Scanning electron microscopy (SEM) of human and rodent peritonea provided a supplementary morphological reference. Imaging and macroscopic evaluations revealed that rats developed more severe and persistent adhesions than mice. This was evidenced by denser CT shadows on day 14 and significantly higher DASI scores on days 7 and 14 (p < 0.01). Histological analysis confirmed more robust collagen deposition and higher expression of profibrotic proteins (TGF-β1 and fibronectin) in rats. SEM findings indicated that the rat peritoneum has more abundant microvilli and a more regular texture, providing a morphological substrate that more closely resembles the human peritoneal surface than that of mice. The rat model exhibits more robust and persistent peritoneal adhesion features than the mouse model, making it a more suitable platform for clinical phenotype studies and translational evaluation. Its morphological similarity to the human peritoneum provides a supplementary structural reference for these interspecies differences.