Comparison of ceramide retention in the stratum corneum between dry skin and normal skin using animal model with fluorescent imaging method

Background/Purpose: Skin care via moisturization compensates for the lack of skin barrier function. However, moisturizer application methods are not clearly decided. Here, we focused on and examined the retention of externally applied ceramide in the stratum corneum (SC) using fluorescent imaging method. This study aimed to compare ceramide retention in the SC between normal skin and dry skin using an animal model. Methods: Nine-week-old Sprague-Dawley rats were divided into two groups: normal skin and dry skin model. The dry skin model group was treated with acetone-diethyl ether solution. A fluorescently labeled ceramide solution was prepared and applied to rats’ back skin. Skin samples were taken at 0 minute and 12 hours after ceramide application. Fluorescently labeled ceramide was evaluated and observed under a microscope. Results: The intensity of externally applied ceramide in the normal skin group showed no significant change from 0 minute to 12 hours after application. In contrast, in the dry skin model group, the intensity of externally applied ceramide increased significantly from 0 minute to 12 hours after application. Conclusion: Our findings demonstrate that the externally applied ceramide penetrated the SC of dry skin more than that of normal skin.