Retinoic acid and CO2 laser resurfacing

The purpose of this study was to analyze the effect of retinoic acid on wou nd healing and depth of injury in an animal skin model resurfaced with a CO 2 laser. The dorsal skin of 21 Hartley guinea pigs was divided into halves. One-half received a daily application of 0.05 % retinoic acid for 28 days, whereas the other half served as the control. The animals were divided into three t reatment groups of seven animals. Group A was laser resurfaced with one pas s of the Coherent UltraPulse CO, laser (300 mJ, 60 W, density 40 percent). Group B received two passes, and group C received three passes. Histologic stud ies were obtained before laser resurfacing and days 1, 4, and 7 after resurfacing. Depth of injury, thickness, number of squamous cell and granul ar cell layers, and epithelialization rates were measured. We found that the depth of injury was statistically less in animals pretrea ted with retinoic acid. Granular cells were thicker and more numerous at da y 4 in pretreated animals but similar to controls by day 7. Animals pre tre ated with retinoic acid overall seemed to heal wounds earlier. In conclusion, pretreatment with retinoic acid may reduce the depth of inju ry in laser resurfacing and speed healing rates.