Soybean Fermented with Bacillus amyloliquefaciens (Cheonggukjang) Ameliorates Atopic Dermatitis-Like Skin Lesion in Mice by Suppressing Infiltration of Mast Cells and Production of IL-31 Cytokine

The present study was conducted with the aim to investigate the ameliorative effects of a new soybean product (cheonggukjang) fermented with Bacillus amyloliquefaciens SCGB1 (SFBA) in atopic dermatitis (AD) mouse model. Visual evaluation of AD induction in the mice indicated the remarkable control of SFBA in reducing the pathological severity of AD-like skin lesions reported as the SCORAD score of AD clinical symptoms. The results revealed that SFBA reduced dorsal skin and epidermal thickness to a similar extent with prednisolone. Further analysis revealed the dominance of SFBA in restraining mast cell infiltration in the dermis; immunoglobulin-E expression in serum; and TH2 IL-4 cytokine and itch-related IL-31 cytokine in the mice skin and serum. SFBA also suppressed scratching behaviours in mice induced by compound 48/80. Further histological findings also revealed the alleviation of collagen fiber deposition in dermal skin of the AD mice model. These actions of SFBA were examined to be mediated by its suppression of the phosphorylation activation of key signalling molecules such as NF-kappaB and MAPK responsible for the induction of cytokine production. Thus, SFBA can be considered as a promising functional food for managing clinical, histological and immunological spectra associated with AD.