095 Comparison of Collagen Nodules and Mast Cells Between Human Hypertrophic Scar and Thick Scar of the Female Red Duroc Pig

Abstract

Introduction: There are several proposed animal models of hypertrophic scarring. However, most are quite dissimilar from the actual human event. It has been shown that wounds on the female, red Duroc pig heal with thick scars. We are attempting to fully validate this model. A fourfold increase in mast cells and formation of collagen nodules have been described as characteristics of human hypertrophic scar. We hypothesized the occurrence of nodules and mast cells in Duroc scars is similar. Methods: For nodules, we biopsied human hypertrophic scars (47 cases) taken 5 to 67 months from injury and Duroc scars (six animals) taken 0 to 5 months from injury. For mast cells, we biopsied human hypertrophic scar (five cases) taken 24 to 30 months from injury and Duroc scars (five animals) taken 5 months from injury. We stained the sections with hematoxylin and eosin (nodules) and Giemsa (mast cells) and counted intact mast cells in the upper papillary dermis in 20 and recorded nodules as present or absent. Results: The results are included the table below. Tissue Month n Nodules mean ± SD P Duroc Scar 0–3 10 0 4–5 6 50% NODULES Human Hypertrophic 5–12 9 33% 12–24 22 36% 24–67 16 81% MAST CELLS Duroc Scar 4–5 5 41 ± 26 <.05 Duroc Uninjured 5 18 ± 9 Human Hypertrophic 24–30 5 251 ± 139 <.01 Human Uninjured 5 60 ± 24 Conclusion: Collagen nodules and increased numbers of mast cells are present in Duroc scar giving further validity to the female, red Duroc pig as an animal model of hypertrophic scarring.