Treatment of allergic rhinitis with CpG oligodeoxynucleotides alleviates the lower airway outcomes of combined allergic rhinitis and asthma syndrome via a mechanism that possibly involves in TSLP

<b>Purpose:</b> Thymic stromal lymphopoietin (TSLP) is a critical regulator of immune responses associated with Th2 cytokine-mediated inflammation. Intranasal administration of oligodeoxynucleotides with CpG motifs (CpG-ODNs) might improve lower airway outcomes of combined allergic rhinitis and asthma syndrome (CARAS), but the inherent mechanisms of CpG-ODNs are not well defined. This study investigated whether CpG-ODNs treated to upper airway could reduce lower airway TSLP expression as well as whether this reduction could contribute to the alleviation of lower allergic inflammation and airway hyper-reactivity (AHR) in CARAS mice. <b>Materials and Methods:</b> Ovalbumin (OVA)-sensitized BALB/c mice were intranasal OVA exposure three times a week for 3 weeks. CpG-ODNs or an anti-TSLP mAb was administered to a subset of these mice 1 hour after intranasal OVA challenge, followed by 5 days of OVA aerosol challenge. The resulting immunological variables, nasal symptoms, and nasal mucosa and lung tissues pathology were evaluated. TSLP production in the lung tissues and bronchoalveolar lavage fluid (BALF) were determined by RT-PCR, western blotting or enzyme-linked immunosorbent assay. <b>Results:</b> The CARAS mice exhibited overexpression of TSLP in the lung tissues and BALF, and also demonstrated significant increases in BALF and splenocyte Th2-associated cytokine production, serum OVA-specific IgE, nose and lung pathologies, and AHR. Intranasal administration of CpG-ODNs restored TSLP in the lower airway, and it significantly reduced the following parameters: Th2-type cytokine production levels; the percentage of eosinophils in the BALF; IL-4 and IL-5 concentrations in the supernatants of cultured splenic lymphocytes; serum OVA-specific IgE; peribronchial inflammation score in the lungs; and nose pathology and nasal symptoms. Similar results were obtained when the CARAS mice were treated with an anti-TSLP mAb to block intranasal TSLP activity. <b>Conclusions:</b> Treatment with intranasal CpG-ODNs improves lower airway immunological variable outcomes in the CARAS model via a mechanism that possibly involves in suppressing pulmonary TSLP-triggered allergic inflammation.

<b>研究目的：</b>胸腺基质淋巴细胞生成素（Thymic stromal lymphopoietin, TSLP）是介导Th2细胞因子相关炎症的免疫应答关键调控因子。经鼻给予含CpG基序的寡脱氧核苷酸（CpG-ODNs）或可改善过敏性鼻炎哮喘综合征（CARAS）的下呼吸道预后，但CpG-ODNs发挥作用的内在机制尚未明确。本研究旨在探讨经鼻给予CpG-ODNs是否可下调下呼吸道TSLP的表达，以及该下调作用是否可缓解CARAS模型小鼠的下呼吸道过敏性炎症与气道高反应性（AHR）。
<b>材料与方法：</b>经卵清蛋白（OVA）致敏的BALB/c小鼠每周经鼻给予OVA刺激3次，持续3周。在经鼻OVA激发1小时后，对部分小鼠给予CpG-ODNs或抗TSLP单克隆抗体干预，随后连续5天给予OVA气溶胶激发。随后对各组小鼠的免疫学指标、鼻部症状、鼻黏膜与肺组织病理特征进行评估。采用逆转录聚合酶链反应、蛋白质印迹法及酶联免疫吸附试验检测肺组织与支气管肺泡灌洗液（BALF）中的TSLP表达水平。
<b>结果：</b>CARAS模型小鼠的肺组织与BALF中可见TSLP过表达，同时BALF与脾细胞分泌的Th2相关细胞因子水平、血清OVA特异性IgE水平、鼻与肺组织病理损伤程度及AHR均显著升高。经鼻给予CpG-ODNs可下调下呼吸道TSLP的表达，并显著降低以下指标：Th2型细胞因子分泌水平、BALF中嗜酸性粒细胞占比、体外培养脾淋巴细胞上清液中IL-4与IL-5的浓度、血清OVA特异性IgE水平、肺部支气管周围炎症评分，以及鼻部病理损伤与鼻部症状。使用抗TSLP单克隆抗体阻断经鼻途径的TSLP活性后，CARAS模型小鼠可获得相似的改善效果。
<b>结论：</b>经鼻给予CpG-ODNs可通过抑制肺部TSLP介导的过敏性炎症这一潜在机制，改善CARAS模型小鼠的下呼吸道免疫学指标预后。