Comedolytic effect of topical retinaldehyde in the rhino mouse model

Background: Retinaldehyde is a key molecule in the metabolism of vitamin A by keratinocytes. In order to evaluate its range of topical activity in acn e, its comedolytic effect was compared to that of retinoic acid in the same vehicle, in the rhino mouse model. Methods: The animals were treated on th e back daily for 5 consecutive days per week for 3 weeks. At the end of thi s period, histological slides were analyzed in order to quantify the featur es of comedones and epidermal thickness. Results: Topical treatment with a retinaldehyde (0.05% w/w) and a retinoic acid formulation (0.025% w/w) indu ced comedolysis and increased the epidermal thickness with the same intensi ty. Conclusion: These data indicate that retinaldehyde exerts a significant comedolytic activity.