Histomorphometric analysis of excisional cutaneous wounds with different diameters in an animal model

The skin wound model in rats is a fundamental stage in preclinical trials, but there is a lack of standardization in these trials regarding the initial wound area, making analysis and comparison between studies difficult. Therefore, this study evaluates the healing progression of excisional skin lesions of varying diameters in Wistar rats, aiming to identify the optimal wound size for monitoring treatment effects on wound healing. Excisions of 0.8, 1.5, 2.0 and 3.0 cm in diameter were made on the back of the animals. Thirty animals were used per treatment and evaluated on days 3, 7, 10, 14 and 21 after surgery. The lesions were cleaned daily with saline solution until they were completely closed. The 0.8 cm group showed complete repair on D14, while in the other groups, the wounds persisted until day 21, with a reddened surface and no complete epidermal coverage, but with greater keratinization and presence of appendages in the 1.5 cm lesions. Therefore, as a standardization model for creating skin wounds, we suggest using 1.5 or 2.0 cm excisions, considering that 0.8 cm wounds close very early and 3.0 cm wounds, although behaving similarly to 2.0 cm wounds, are more invasive for the animals. The 1.5 cm model proved to be suitable for closure within 21 days. When evaluating a product intended to accelerate wound healing, 2.0 cm lesions are recommended to assess the effectiveness of the treatment.