Reepithelialization of deep
burns requires spontaneous or active removal or
debridement of the necrotic eschar, as recently defined by the American
Burn Association.
Debrase is a
bromelain-derived enzymatic preparation that has been shown to result in rapid and selective
debridement of human and animal
burns. The authors hypothesized that rapid
debridement of deep dermal
burns with
Debrase would result in earlier reepithelialization of the remaining dermis in a porcine model. Eighty deep dermal contact
burns measuring 10 by 20 mm were created on the back and flanks of anesthetized domestic pigs (25 kg) using a
brass template preheated in boiling water (100 degrees C) that was applied to the skin for a period of 30 seconds. The template was applied using a spring-loaded device designed to control the amount of pressure applied to the skin by the template.
Burns were randomized to a 4-hour topical application of
Debrase (lyophilized dry
enzyme dissolved and activated in a hydrating vehicle) (n = 40) or its hydrating vehicle (n = 40) followed by daily application of a
petrolatum-based
antibiotic ointment.
Wounds were visually assessed and photographed daily. Four-millimeter full-thickness punch biopsies were obtained for histological analysis using
hematoxylin and
eosin staining by a board-certified dermatopathologist masked to
burn therapy at 7, 11, 13, and 15 days after injury. The primary outcome was the percentage of the
burns that were completely reepithelialized at each time point. Secondary outcomes were time to complete reepithelialization and the mean percentage of reepithelialization on microscopic analysis. A sample of 40
burns in each group had 80% power to detect a 20% difference in the percentage of completely reepithelialized
burns (two tailed, P < .05). The percentage of completely reepithelialized
burns was higher for
Debrase than control
burns at days 11 (40.9% vs 3.1%; P = .002), 13 (87.5% vs 50%; P = .007), and 15 (97.5% vs 77.5%, P = .018). The mean (SD) percentage reepithelialization of
Debrase-treated
burns at 7 days was higher than of control
burns (47.6% [3.2] vs 0% [0]; P < .001). A larger number of cells in the epidermis and dermis of debrided
burns stained positive for the proliferation
antigen Ki-67. There was no evidence of any adverse events in the normal skin adjacent to the
Debrase-treated
burns. Rapid enzymatic
debridement of deep partial-thickness
burns with
Debrase results in earlier reepithelialization and cellular proliferation in swine, when compared with carrier and topical
antibiotic dressings alone.