低聚甘露糖对2,4-二硝基氟苯致小鼠特异性皮炎的改善作用研究

Effect of Mannose Oligomer on Atopic Dermatitis Model Mice

目的:建立小鼠特异性皮炎(Atopic dermatitis,AD)模型,观察低聚甘露糖(Mannose oligosaccharide,MOS)对小鼠AD的改善作用,并初步探讨其在免疫方面的作用机制。方法:将32只雄性昆明小鼠,随机分为正常组、AD模型组、MOS治疗组以及地塞米松(Dexamethasone,DEX)阳性对照组。采用2,4-二硝基氟苯(2,4-dinitrofluorobenzene,DNFB)反复诱导建立小鼠AD模型,共造模2周。造模第1天分别用纯水、MOS和DEX灌胃,1次/d。造模期间,动态观察并记录各组小鼠背部皮损变化以及瘙痒次数。于给药第15天处死小鼠,计算小鼠脾脏指数、胸腺指数,检测血清免疫球蛋E(Immunoglobulin-E,IgE)以及全血白细胞含量,同时取背部皮肤进行HE(Hematoxylin-Eosin,HE)染色、甲苯胺蓝染色观察其病理变化情况。免疫组化检测皮肤组织CD4^+T浸润情况。ELISA法测定各组小鼠血清以及皮损中白细胞介素-4(Interleukin-4,IL-4)和γ-干扰素(Interferon-γ,IFN-γ)水平。结果:MOS能有效减轻AD小鼠引起的免疫器官肿大,减轻皮损炎症程度,减少皮肤组织肥大细胞及CD4+T浸润数量,调节AD小鼠血清和皮损中IL-4和IFN-γ水平。结论:MOS可能通过调控Th1/Th2免疫细胞因子平衡,从而抑制了AD模型小鼠的炎症反应。

Objective:To study the therapeutic effect and its possible mechanism of action of mannose oligomer on atopic dermatitis(AD) in mice.Methods:Thirty-two mice were randomly divided into 4 groups:blank group,AD model group,mannose oligomer group and dexamethasone group.The AD model in mice was induced by repeated topical application of 2,4-dinitrofluorobenzene(DNFB).The mice were fed respectively with pure water,mannose oligomer and dexamethasone by gavage once a day from the first day of modeling.During the experiment,we dynamically observed and recorded the changes of the degree of skin lesions and scratching behaviors of each mice.On the 15 th day after sacrifice,spleen and thymus index of mice were calculated.Serum immunoglobulin-E(Ig E),white blood cells contents of mice in each group were detected.In the meantime,Paraffin-embedded skin section was stained with either hematoxylin and eosin(H & E) to visualize epidermal thickness and infiltration of various inflammatory cells or toluidine blue to quantify mast cells.The infiltration of CD4^+T in skin tissue was detected by immunohistochemistry.The levels of interleukin-4(IL-4),interferon-γ(IFN-γ) in serum and skin tissue were determined by ELISA method.Results:Mannose oligomer can effectively alleviated DNFB-induced AD skin symptoms of mice,as evidenced by the downregulation of Ig E levels in serum,significant reduction in immune organ enlargement and decreased infiltration of mast cells,CD4^+T and inflammatory cells in the skin lesions.In addition,the levels of IL-4 and IFN-γ in serum and skin tissue were decreased significantly after treatment with mannose oligomer.Conclusion:Mannose oligomer exhibited its therapeutic value for the prevention and clinical treatment of AD,possibly ascribing to downregulation of both Th1 and Th2 cytokines.