Oral administration of pineapple glucosylceramide improves defective epidermal barrier function by restoring diminished level of TGF-β in the skin

Abstract

It was reported that oral administration of glucosylceramide (GlcCer) from plants ameliorates skin barrier function. GlcCer is a type of glycosphingolipid that exists widely as a component of the cell membrane. However, the mechanism of improvement by dietary GlcCer is not completely understood. The aim of the present study was to investigate the mechanism of GlcCer in the improvement of skin barrier function. Five-week-old male Hos:HR-1 mice were divided into three groups fed on standard diet, unsaturated fatty acids-deficient (HR-AD) diet, and HR-AD diet supplemented with 0.1% P-GlcCer diet. Skin barrier function was evaluated by transepidermal water loss (TEWL) value and wrinkle formation. The effect of transforming growth factor-β (TGF-β) on skin barrier function and collagen content in skin was examined using exogenous TGF-β and its neutralizing antibody. TEWL value and wrinkle formation were decreased by oral administration of pineapple (P)-GlcCer. Not only the TGF-β contents in serum and skin but also hydroxyproline content reduced by the HR-AD diet were restored by P-GlcCer administration. Exogenous TGF-β ameliorated both skin barrier function and collagen contents. However, the improvement of skin barrier function by P-GlcCer was cancelled and collagen content in skin was also decreased by TGF-β antibody injection. Recovery of TGF-β content by P-GlcCer contributed to the production of collagen in skin, resulting in improved skin barrier function.