特应性皮炎小鼠中Th1/Th2类细胞因子失衡对神经生长因子表达的影响

Effect of Th1 / Th2 cytokine immune imbalance on the expression of nerve growth factors in atopic dermatitis mice

目的 初步探讨特应性皮炎(AD)小鼠中Th1/Th2 类细胞因子失衡对脾淋巴细胞神经生长因子(NGF) mRNA 表达的影响.方法 用卵清蛋白经皮肤致敏建立小鼠AD模型, ELISA测定血清总IgE水平.分离脾淋巴细胞并培养.逆转录-聚合酶链反应(RT-PCR)半定量法测定细胞在刀豆素A(ConA)刺激下表达NGF mRNA的基础水平及γ-干扰素(IFN-γ)和白细胞介素-4(IL -4)干预后NGF mRNA表达改变.结果 ①AD小鼠脾淋巴细胞在基础状态下具有表达NGF mRNA的功能,在12、24、36、48 h时基础NGF mRNA表达量随着时间的延长逐渐升高,IL-4组(50 μg/L)随着时间的延长基础NGF mRNA表达量逐渐升高,并高于同时间空白对照组(P均<0.01). 相反, IFN-γ组(25 μg/L)的NGF mRNA水平随时间逐渐下降,并均低于同时间空白对照组(P均<0.01).②干预24 h时,随着IL-4干预浓度的增加,NGF mRNA的表达水平亦升高,并且分别与前一梯度低浓度干预组比较差异有统计学意义(P均<0.01),随着IFN-γ干预浓度的增加, NGF mRNA的表达水平却逐渐减低,分别比前一梯度低浓度干预组有显著降低(P均<0.01).结论 在特应性皮炎中Th2类细胞因子IL-4可上调淋巴细胞NGF mRNA表达,Th1类细胞因子IFN-γ可下调淋巴细胞NGF mRNA表达,两者均呈时间和浓度依赖性,Th1 / Th2类细胞因子免疫失衡可能通过调控NGF mRNA 表达间接促进其诱导神经源性炎症.

Objective To explore the effect of Th1 / Th2 cytokines on the expression of nerve growth factor (NGF) in splenic lymphocytes in atopic dermatitis mice.Methods Four AD mice were sensitized and challenged with ovalbumin to establish AD model, and serum IgE level was measured by ELISA.The mouse splenic lymphocytes were isolated and cultured with ConA. The expressions of NGF mRNA were detected by RT-PCR, and were observed after the lymphocytes were exogenously added with interferon -γ(IFN-γ) or interleukin-4 (IL-4). Results ①The lymphocytes of the AD model stimulated by ConA in vitro expressed NGF mRNA in a time-dependent manner. After the lymphocytes had been cultured with IL-4 for 12 h, 24 h, 36 h, and 48 h, 50μg/L IL-4 upregulated the expressions of NGF mRNA in a time-dependent manner and all the NGF mRNA expressions were significantly higher than the basal values at the same time (P all<0.01), however,25μg /L IFN-γ downregulated the expressions of NGF mRNA in a time-dependent manner and all the NGF mRNA expressions were significantly lower than the basal values at the same time (P all<0.01).②The lymphocytes of the AD model stimulated by ConA in vitro also expressed NGF mRNA in a dose-dependent manner.After 0,10, 25,50, and 100 μg /L IL-4 had been added for 24 h, IL-4 upregulated the expressions of NGF mRNA in a dose-dependent manner and the NGF mRNA expressions were all significantly higher than the values of the lower dose IL -4 (P all <0.01), however,after 0, 1, 10, 25,and 50μg /L IFN-γ had been added for 24 h, IFN-γ downregulated the expressions of NGFmRNA in a dose-dependent mannerand all the NGF mRNA expressions were significantly lower than the values of the lower IFN-γ dose (P all<0.01).Conclusions In the splenic lymphocytes of atopic dermatitis mice, IL -4, one of the Th2 cytokines, can upregulate the expressions of NGF, IFN-γ, one of the Th1 cytokines, can downregulate the expressions of NGF both in a time-dependent manner and in a dose-dependent manner. Th1 /Th2 cytokine immune imbalance may indirectly induce the skin neurogenic inflammation by regulating the NGF mRNA expression.