Dermal fibroblasts from red Duroc and Yorkshire pigs exhibit intrinsic differences in the contraction of collagen gels

Previous studies have shown that the Yorkshire (Y) pig is a model for normal skin wound healing, while red Duroc (RD) pigs form hypercontracted scars similar to human hypertrophic scars. In order to determine potential intrinsic differences in fibroblast phenotypes, the ability of normal dorsal and ventral dermal fibroblasts from Y and RD pigs to contract collagen gels was assessed. Cells plated in gels were cultured in media supplemented with 2% or 10% FBS +/- 1 or 10 ng/mL transfroming growth factor beta 1. The degree of contraction of the gels was quantified at defined time-points postrelease. Final contraction levels were dependent on cell density and serum concentration for all cell types. The rates of contraction of RD dorsal fibroblasts were significantly greater than those for Y dorsal fibroblasts. Immunocytochemical analysis revealed the presence of alpha-smooth muscle actin in contracted cells. Furthermore, mRNA levels for matrix metalloproteinase-2 and decorin showed specific increases for the RD cells during contraction. These findings have revealed intrinsically different, location-specific in vitro responses with normal dermal fibroblasts from the two breeds of pig, suggesting that the abnormal skin healing phenotype of RD pigs may be attributable in part to intrinsic genetic differences in fibroblasts between the breeds.