Further similarities between cutaneous scarring in the female, red Duroc pig and human hypertrophic scarring

Abstract

Knowledge of the pathophysiology of hypertrophic scarring following deep dermal injuries is minimal due to the lack of an animal model. We previously confirmed that thick scars in female, red Duroc pigs (FRDP) are similar to human hypertrophic scar. The purpose of this study was to evaluate TGFβ1, IGF-1, decorin, and versican expression in FRDP wounds. Deep and shallow wounds on the backs of two FRDPs were studied over 5 months. Immunohistochemistry was performed for TGFβ1, IGF-1, decorin, and versican. TGFβ1 and IGF-1 mRNA were evaluated by in situ hybridization and RT-PCR. In shallow wounds (1) TGFβ1 protein was not detectable and IGF-1 protein was seen at 10 days post-wounding. TGFβ1 and IGF-1 mRNA were elevated for 30 days. (2) Decorin protein was not detected at 10th day, but returned to levels of uninjured skin. (3) Versican protein was not detectable at any time. In deep wounds, (1) TGFβ1 and IGF-1 protein and mRNA were elevated early, (2) decorin protein was greatly reduced for the first 90 days, and (3) versican protein was present from 30 to 150 days. These findings correlate with findings reported in the literature for human hypertrophic scar and further validate the FRDP model of hypertrophic scarring.