地塞米松对变应性鼻炎小鼠调节性T细胞表达的作用研究

Effect of dexamethasone on the expression of Tregs in allergic rhinitis mice

目的:研究变应性鼻炎(AR)小鼠体内调节性T细胞(Tregs)变化及地塞米松(DEX)对AR小鼠Tregs表达的影响,初步探讨糖皮质激素治疗AR的作用机制。方法:采用卵清蛋白(OVA)致敏和激发建立AR小鼠模型,腹腔注射DEX进行干预治疗。通过行为学观察了解DEX改善AR症状的作用。取鼻腔组织行苏木精-伊红染色,观察其形态学特点;取脾组织研磨后获得单个核细胞,提取总RNA行RT-PCR检测Foxp3mRNA表达情况;通过流式细胞仪检测脾细胞中CD4+Foxp3+T细胞含量变化。结果:AR组10min内喷嚏和搔鼻频率[分别为(44.50±5.61)次和(72.94±8.76)次]明显高于正常对照组[分别为(12.68±1.87)次和(26.76±2.89)次],两组比较差异有统计学意义(P<0.01);经DEX治疗后,喷嚏和搔鼻频率[分别为(26.04±3.93)次和(56.79±5.64)次]显著下降,与AR组相比差异有统计学意义(P<0.01)。AR组小鼠鼻黏膜纤毛柱状上皮连续性破坏,黏膜下大量炎症细胞浸润;DEX治疗后鼻黏膜炎症细胞浸润明显减少,鼻黏膜上皮完整性修复良好。DEX组小鼠脾脏单个核细胞的Foxp3mRNA表达均高于AR组和正常对照组(P<0.05)。AR组CD4+Foxp3+T细胞含量为(3.89±0.39)%,较正常对照组(4.63±0.15)%降低(P<0.05);DEX治疗后CD4+Foxp3+T细胞含量为(6.89±0.49)%,与AR组相比差异有统计学意义(P<0.05)。结论:DEX可有效改善上气道变应性炎症,可能与上调Foxp3表达、扩增体内Tregs有关。

Objective：To investigate the effect of dxamethasone（DEX）on the expression of Tregs in allergic rhinitis（AR）mice,and explore the mechanism of glucocorticoid in the treatment of AR.Method：AR murine model was established by sensitization and challenge with OVA,besides intervention treatment with DEX was carried out in AR model.The behavior observation was used to evaluate the improvement effect of DEX on AR symptoms.The morphological characteristics of nasal tissues were observed by HE staining after fixation and decalcification.The mononuclear cells were obtained by grinding spleens,and the total RNA was extracted for reverse transcriptase polymerase chain reaction to investigate the level of mRNA expression of Foxp3.The changes of CD4＋Foxp3＋Tcells in spleen of mice were analyzed by flow cytometry.Result：BALB/c mice received OVA sensitization followed by OVA intranasal challenge,the frequencies of sneezing and nose-scratching increased significantly in AR group（44.50±5.61 and 72.94±8.76）compared with control group（12.68±1.87 and 26.76±2.89）,P〈0.01;The frequencies decreased significantly in DEX group（26.04±3.93 and 56.79±5.64）,P〈0.05 compared with AR group.The continuity of nasal mucosa ciliated columnar epithelium in AR group was destroyed and appeared to be repaired in DEX group.Inflammatory cells infiltration was also markedly decreased by DEX treatment.The proportion of CD4＋Foxp3＋T cells in AR group（3.89±0.39）% decreased,P〈0.01 vs control group（4.63±0.15）%.DEX treatment induced production of Tregs（6.89±0.49）%,P〈0.05 vs control group.DEX significantly increased the expression of Foxp3mRNA（P〈0.05）compared with AR and control group.Conclusion：DEX reduce upper airway allergic inflammation effectively,which may be mediated by promoting the expression of Foxp3 and inducing the amplification of Tregs in vivo.