Modulation of scarring in a liquid environment in the Yorkshire pig

Decreased inflammatory response seen in wet wound healing may be correlated with diminished scarring. This study seeks to test this hypothesis and to validate a model of scarring in the Yorkshire pig. Four Yorkshire pigs were used to create 36 dorsal wounds per pig (144 wounds total) in the following groups: full-thickness excisional, partial thickness, meshed split-thickness skin grafts, sheet split-thickness skin grafts, minced skin, and incisional wounds. Wounds were randomized into wet and dry groups. Wet wounds were enclosed in polyurethane chambers with 2 mL of normal saline. Dry wounds were covered with regular gauze. Terminal biopsies were performed at 72 hours and day 28. Histology demonstrated significantly less inflammatory infiltrate, thicker neoepidermis, more pronounced rete ridge formation, and decreased scar tissue thickness in wet wounds. The mean macroscopic scar surface area was significantly decreased in full-thickness excisional wet wounds compared with dry wounds (61.2 mm2 vs. 150.8 mm2, p < 0.01). Hydroxyproline content was decreased in full-thickness wet compared with dry groups (44.81 vs. 62.21 mg/g, p < 0.01). Tensile strength was 90% greater in full-thickness wet compared with dry groups (p < 0.01). Healing in the liquid environment significantly reduced scar formation. This model will allow for future investigation of high-concentration topical scar-modulating agents in the liquid environment.