Dietary Fermented Soybean Suppresses UVB-Induced Skin Inflammation in Hairless Mice via Regulation of the MAPK Signaling Pathway

Soybean may be a promising ingredient for regulating UVB-induced inflammatory damage to the skin. We investigated the anti-inflammatory effects of diets supplemented with fermented soybean on UVB-induced skin photodamage and the effectiveness of soybean (S) and fermented soybean (FS) dietary supplementation. To investigate the effects of two major isoflavonesdaidzein and genisteinfrom FS, we used cocultures with keratinocytes and fibroblasts. Genistein treatment strongly inhibited the production of IL-6 and MAPK signaling. Forty hairless male mice divided into four groups were fed with a control diet (group N: normal, group C; +UVB) or diets with 2.5% S+UVB or 2.5% FS+UVB (group S, group FS) for 8 weeks. Macrophage infiltration to the dermis was reduced more in groups S and FS than in group C. The expression levels of iNOS and COX-2 were significantly decreased in group FS (by 7.7% +/- 0.4% and 21.2% +/- 0.3%, respectively [p < 0.05]).