A Rat Excisional Wound Model for Investigating Therapeutics in Critical-Size Skin Wounds.

Skin wounds represent a major global healthcare challenge, creating substantial morbidity and economic burden. Reliable and clinically relevant animal models are essential for investigating mechanisms of tissue repair and evaluating emerging therapeutic strategies. However, conventional rodent excisional wound models are limited by rapid wound contraction due to the panniculus carnosus, which differs significantly from human wound healing. The latter predominantly occurs through granulation tissue formation and re-epithelialization. This study describes a rat excisional wound model designed to limit wound contraction while providing a protected environment for testing sensitive therapeutic interventions. Full-thickness 10-mm dorsal excisional wounds were created in Sprague Dawley rats and stabilized using a nitrile butadiene rubber (NBR) O-ring secured with interrupted sutures. To maintain a moist wound environment, an Eakin cohesive seal and transparent adhesive film were applied to form a chamber suitable for topical administration of cells, biomaterials, or pharmaceutical compounds. Additional protective layers consisting of a foam dressing, adhesive tape, a tubular bandage, and a double-shoulder fixation system were used to prevent the animals from removing the dressing. Wound healing was monitored over 14 days by digital planimetry and histological assessment using hematoxylin and eosin staining. The procedure required approximately 30 min per animal and yielded consistent wound-healing outcomes. The NBR O-ring was used as a splint to limit wound contraction. Healing occurred primarily through granulation tissue formation and re-epithelialization. Dressings remained intact for up to seven days without evidence of infection. Histological analysis demonstrated active tissue repair characterized by epidermal regeneration and inflammatory cell infiltration. This model provides a platform for preclinical evaluation of wound therapeutics and advanced regenerative treatments.