Xi Yu1, Yan Niu1, Jie Zheng1, Hailiang Liu1, Guorong Jiang2, Junhao Chen3, Min Hong4. 1. Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Jiangsu Key Laboratory of Pediatric Respiratory Disease, Nanjing University of Chinese Medicine, Nanjing 210023, China. 2. Suzhou Hospital of Traditional Chinese Medicine, Suzhou 215000, China. 3. Center of Clinical Laboratory, Gulou Hospital, Nanjing, PR China. 4. Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Jiangsu Key Laboratory of Pediatric Respiratory Disease, Nanjing University of Chinese Medicine, Nanjing 210023, China. Electronic address: hongmin72@126.com.
Abstract
BACKGROUND: Radix Saposhnikovia (RS), called "Fangfeng" in China, is commonly used in Chinese medicinal formulae to treat allergic and inflammatory diseases. However, the underlying mechanisms of RS in ameliorating allergy remain unknown. PURPOSE: To study the effects of RS extract on allergic contact dermatitis (ACD) in a mouse model and to investigate the underlying mechanisms in vivo and ex vivo. METHODS: ACD was induced by sensitizing the mice and treating an ear auricle with 1-chloro-2,4-dinitrobenzene (DNCB). RS extract was administered during the sensitization and/or elicitation phase. Ear swelling was noted and lymphocytic infiltration was investigated with hematoxylin and eosin staining. The cytokines in the sera and the supernatants of lymphocyte cultures were determined with enzyme-linked immunosorbent assays. Lymphocyte proliferation was assessed with a 3-(4,5)-dimethylthiazol-2-y1)-2,5-diphenyltetrazolium bromide (MTT) assay. The maturation of dendritic cells (DCs) and the differentiation of T cells were examined with flow cytometry. The mRNA expression of T-bet, GATA-3, and forkhead box p3 (Foxp3) was evaluated with real-time PCR. RESULTS: RS extract (1.3 or 2.6 g/kg) markedly reduced the ear swelling and the intense cellular infiltration of inflammatory cells in the ear tissue. The ratio of interferon γ (IFN-γ)/interleukin 4 (IL-4) was reduced in the sera of the DNCB-sensitized mice and the lymphocyte culture supernatants after treatment with the extract. Further study of the initial stage of ACD revealed that RS extract prevented the differentiation of naïve T cells into Th1 cells, reduced the proportion of CD3(+)CD4(+) (Th) cells, and suppressed the secretion of IFN-γ and the expression of T-bet mRNA in lymphocytes. The RS extract also reduced the proportion of DCs in the sensitized mouse lymphocytes and the expression of CD40(+)CD86(+) cells in the DCs. CONCLUSION: RS extract is effective in treating ACD because it regulates the development of DCs and DC-activated Th1 differentiation.
BACKGROUND: Radix Saposhnikovia (RS), called "Fangfeng" in China, is commonly used in Chinese medicinal formulae to treat allergic and inflammatory diseases. However, the underlying mechanisms of RS in ameliorating allergy remain unknown. PURPOSE: To study the effects of RS extract on allergic contact dermatitis (ACD) in a mouse model and to investigate the underlying mechanisms in vivo and ex vivo. METHODS: ACD was induced by sensitizing the mice and treating an ear auricle with 1-chloro-2,4-dinitrobenzene (DNCB). RS extract was administered during the sensitization and/or elicitation phase. Ear swelling was noted and lymphocytic infiltration was investigated with hematoxylin and eosin staining. The cytokines in the sera and the supernatants of lymphocyte cultures were determined with enzyme-linked immunosorbent assays. Lymphocyte proliferation was assessed with a 3-(4,5)-dimethylthiazol-2-y1)-2,5-diphenyltetrazolium bromide (MTT) assay. The maturation of dendritic cells (DCs) and the differentiation of T cells were examined with flow cytometry. The mRNA expression of T-bet, GATA-3, and forkhead box p3 (Foxp3) was evaluated with real-time PCR. RESULTS:RS extract (1.3 or 2.6 g/kg) markedly reduced the ear swelling and the intense cellular infiltration of inflammatory cells in the ear tissue. The ratio of interferon γ (IFN-γ)/interleukin 4 (IL-4) was reduced in the sera of the DNCB-sensitized mice and the lymphocyte culture supernatants after treatment with the extract. Further study of the initial stage of ACD revealed that RS extract prevented the differentiation of naïve T cells into Th1 cells, reduced the proportion of CD3(+)CD4(+) (Th) cells, and suppressed the secretion of IFN-γ and the expression of T-bet mRNA in lymphocytes. The RS extract also reduced the proportion of DCs in the sensitized mouse lymphocytes and the expression of CD40(+)CD86(+) cells in the DCs. CONCLUSION:RS extract is effective in treating ACD because it regulates the development of DCs and DC-activated Th1 differentiation.