Oral administration of Cervus nippon mantchuricus extract suppresses 2,4-dinitrochlorobenzene-induced atopic dermatitis in BALB/c mice and inflammatory effects in mast cells

Cervus nippon mantchuricus extract, known as nok-gol (NGE) in Korean, is useful for the treatment of various inflammatory diseases, including bone resorption and neutropenia. However, NGE has not been widely investigated, and its efficacy and safety remain to be fully elucidated. In the present study, histological analysis, blood analysis, reverse transcription-semi-quantitative polymerase chain reaction analysis and enzyme-linked immunosorbent assays were performed to verify the inhibitory effect of NGE on atopic dermatitis (AD) in BALB/c mice and on inflammatory effects in HMC-1 human mast cells. NGE suppressed the development of AD in mice, and decreased the infiltration of inflammatory cells, mast cells and CD4(+) T cells into AD skin lesions. NGE also decreased leukocyte levels induced by 2,4-dinitrochlorobenzene (DNCB). NGE alleviated AD-like inflammatory symptoms in mice by suppressing the production of CD4(+) T cells. NGE downregulated the mRNA expression of inflammatory cytokines induced by DNCB. It also decreased the serum immunoglobulin E concentration and inflammatory cytokine levels in DNCB-treated BALB/c mice. The in vitro experiments demonstrated that NGE reduced the phorbol 12-myristate 13-acetate + ionomycin-induced expression of pro-inflammatory cytokines interleukin (IL)-4, IL-13, tumor necrosis factor-, and IL-6 in HMC-1 cells. Taken together, the results of the present study indicated that NGE suppressed the progression of DNCB-induced AD in BALB/c mice and reduced inflammatory effects in HMC-1 cells. This suggests that NGE may be a useful drug for the treatment of AD.