Dietary Whey Protein Hydrolysate Suppresses Development of Atopic Dermatitis-like Skin Lesions Induced by Mite Antigen in NC/Nga Mice

Background：Oral administration of enzymatic hydrolysate of cow's milk whey protein (WPH) has been reported to produce an anti-inflammatory effect. Since inflammation plays a role in dermatitis of allergic disease, we examined the influence of WPH on the development of atopic dermatitis (AD)-like skin lesions, induced in NC/Nga mice by the mite antigen Dermatophagoides pteronyssinus (Dp). Methods：AD-like skin lesions were induced on the pinnae and backs of NC/Nga mice by daily application of Dp for 4 weeks. Mice were fed cow's milk casein (control), WPH or casein protein hydrolysate (CPH) diets for 2 weeks prior to Dp application. Clinical skin conditions were evaluated periodically by a clinical severity score, total serum IgE and soluble E-selectin levels were measured by enzyme linked immunosorbent assay (ELISA). Results：WPH-fed mice showed significantly less AD-like skin lesions than those fed casein diets at 2 and 4 weeks after Dp application. In contrast, CPH-fed mice had manifestations in a similar manner as casein-fed mice did, and did not show an inhibitory effect. Serum soluble E-selectin levels, known as a marker of disease activity in AD patients, were significantly lower in the WPH diet group. Conclusions： Our results suggest that in addition to its hypoallergenicity an anti-inflammatory function, dietary WPH might be useful for reducing the severity of AD-like skin lesions.