THE EFFECTS OF TRETINOIN ON RANDOM SKIN FLAP SURVIVAL IN THE SWINE MODEL

Tretinoin is currently marketed for topical treatment of acne vulgaris and has also been used in the rejuvenation of aging skin. After topic al application, it has been shown to stimulate mitotic activity and in crease vascularity in skin. In this study a porcine model was used to test the hypothesis that presurgical treatment with topical tretinoin would increase the surviving area of random full-thickness skin flaps. Four hybrid barrows, 40 to 60 lb, were treated with tretinoin and 4 s imilar animals were treated with placebo (carrier vehicle) for 2 weeks before raising four dorsally based full-thickness skin flaps (4 x 12 cm) on each animal. Biopsies were taken from tretinoin-treated, placeb o-treated, and untreated skin at the time the flaps were initially rai sed and 1 week later before killing the animals. All tissue was proces sed for light and electron microscopy. One week after surgery, the pig s were killed. Photographs were taken at the termination of the experi ment and the negatives were digitized and analyzed using a high-speed graphics workstation supported by sGITrace software. The percentage of skin flap survival was determined using this method of image analysis . Using repeated-measures analysis of variance, there was no significa nt difference in the mean flap survival between the tretinoin (mean = 46.75; SEM = 7.05) and placebo (mean = 65.80; SEM = 7.05) treated grou ps at the 0.05 significance level. Pretreatment with tretinoin did not enhance skin flap survival under the conditions of this study. Ration ale for this finding and possible modifications of future studies are discussed.