Genetic Involvement in Skin Wound Healing and Scarring in Domestic Pigs: Assessment of Molecular Expression Patterns in (Yorkshire × Red Duroc) × Yorkshire Backcross Animals

Yorkshire, red Duroc, and F1 (first-generation cross) pigs heal with normal, fibroproliferative/hypercontractile, and intermediate levels of scarring, respectively. The purpose of this study was to evaluate the healing phenotype of Yorkshire × F1 backcross animals, to address the molecular basis for genetic transmission of the red Duroc scarring phenotype. Macroscopically and histologically, full-thickness wounds on backcross animals followed the Yorkshire phenotype, with one exception; the backcross wounds exhibited contraction following re-epithelialization. The molecular expression patterns in the backcross animals generally correlated with the macroscopic and histologic findings. Compared to Yorkshire, red Duroc, and F1 wounds, the backcross wounds demonstrated a diminished initial inflammatory phase, followed by a prolonged expression of several relevant growth factors. Additionally, collagen expression was prolonged, expression of matrix metalloproteinases was increased, and alterations in tissue inhibitor of metalloproteinase expression were detected. Moreover, a subset of molecules still followed the red Duroc pattern of mRNA expression, a finding that allows for correlations between the scarring phenotype and the molecular expression patterns to be made in this model. The results indicate that a number of genes are likely involved in the red Duroc healing phenotype and that identification of the specific genes involved will require a more detailed genomic analysis.