Validation of a rat parastomal hernia model for evaluating mesh biocompatibility and repair outcomes

The preclinical evaluation of various meshes and surgical techniques for parastomal hernia (PSH) repair is limited due to the lack of a standardized, responsive, and clinically relevant animal model. This study aimed to validate a previously established rat PSH model and evaluate its ability to discriminate the biological and biomechanical properties of diverse meshes.

A total of 24 Sprague-Dawley rats were included in this study. A standardized PSH model was induced by a 3 × 2 cm abdominal wall defect, partial rectus abdominis resection, and functional end-colostomy. Keyhole repair was performed using biological meshes (porcine small intestinal submucosa [SIS] or porcine acellular dermal matrix [ADM]) or synthetic meshes (polyvinylidene fluoride [PVDF] or polypropylene [PP]). The model was validated using metrics such as survival, weight trends, and 8-week host responses, including recurrence/bulging, intestinal adhesion, erosion, inflammation, and angiogenesis.

The model demonstrated excellent surgical feasibility and tolerance. All groups showed 100% survival and stable weight gain. The model sensitively discriminated mesh-specific outcomes. The SIS group exhibited significantly higher recurrence rates than that of the other groups. The ADM group showed minimal inflammation but moderate adhesion formation. Severe adhesions with histologically confirmed erosion into the stoma intestine were observed in the PVDF and PP groups. Significant differences in inflammation and angiogenesis were observed among the four groups.

This rat PSH model provided a validated preclinical platform for evaluating PSH repair strategies and exhibited differential responses among the four meshes in biocompatibility and key repair outcomes.