Collagenase during burn wound healing: influence of a hydrogel dressing and pulsed electrical stimulation

Epithelialization of second-degree burn wounds is known to be accelerated by topical treatment with hydrogel dressings and further enhanced by pulsed electrical stimulation compared with no treatment (air exposure). Tissue collagenase has been proposed to be involved during the process of epithelialization. In the present study collagenase levels were examined in partial-thickness burn wounds in the skin of four domestic pigs. Collagenase levels, assayed on postburn days 1 to 10, were substantially reduced in deblistered and air-exposed burn wounds compared with excisional partial-thickness wounds. Early application of hydrogel dressing to the burn wounds was accompanied by elevated collagenase activities and an increased inflammatory reaction in dermis. Addition of pulsed electrical stimulation increased (p < 0.001) collagenase levels twofold above those with hydrogel alone during initiation of epithelialization (postburn days 3 and 4). These results suggest that collagenase is closely linked to wound epithelialization.