LAUSR

Abstract Sweet whey is a by-product of rennet-type cheese and contains abundant physiologically active substances. In this study, we investigated the effects of sweet whey on keratinocytes in mouse back skins using the warm-bathing model and using human keratinocyte culture model. The low-molecular-mass fraction (less than 3 kDa) of the whey was used for human keratinocyte culture because hydrophilic low mass components can penetrate into the epidermis. The two experimental models revealed that whey treatment activated the proliferation of keratinocytes. Whey treatment also up-regulated the expression of CK10, a marker for differentiated keratinocytes. The expression of epidermal tight junction proteins and aquaporin 3 (AQP3) was also activated by whey treatment expression. Whey contains abundant lactose and calcium. However, neither lactose nor calcium affected proliferation activity and AQP3 expression in cultured keratinocytes. These findings suggest that cheese whey may have potential as a cosmetic ingredient to improve epidermal conditions.