目的研究屋尘螨(HDM)对于气道上皮Toll样受体4(TLR4)表达及T淋巴细胞分化的影响,以进一步探讨其在哮喘小鼠气道炎症中作用。方法雌性BALB/c小鼠30只随机分为OVA哮喘模型组(OVA组)、HDM组和生理盐水对照组(对照组)。OVA组用卵白蛋白(OVA)致敏与激发建立小鼠哮喘模型,HDM组给予HDM提取液替代OVA致敏与激发,对照组用生理盐水替代OVA。观察小鼠气道及肺组织病理炎症浸润情况,支气管肺泡灌洗液(BALF)中细胞总数及细胞分类计数。ELISA检测小鼠BALF上清中IL-4、IL-5、IL-13、IFN-γ和IL-17的含量。实时荧光定量PCR法测定气道上皮TLR4 mRNA的表达,免疫印迹法测定气道上皮TLR4蛋白的表达。流式细胞技术检测小鼠外周血Th1、Th2及Th17淋巴细胞占CD4+T淋巴细胞百分率情况。结果 OVA组支气管黏膜下水肿,黏液腺增生,以嗜酸粒细胞为主的炎症细胞浸润;HDM组出现肺泡腔及间质充血,中性粒细胞等炎症细胞浸润;对照组小鼠气道上皮无增厚,无炎症细胞浸润,肺泡壁完整。与OVA组比较,HDM组BALF细胞总数及分类计数除嗜酸粒细胞无显著差异外(P>0.05),其余均显著升高(P<0.05);HDM组BALF上清中IL-4、IL-5、IL-13及IL-17水平较OVA组明显增高(P<0.05),IFN-γ的表达无显著差异(P>0.05);HDM组气道上皮TLR4 mRNA及TLR4蛋白的表达明显增高(P<0.05),OVA组与对照组差异无统计学意义(P>0.05)。与OVA组比较,HDM组外周血Th2、Th17细胞显著增高(P<0.05),而Th1细胞无明显变化(P>0.05)。结论 HDM诱导气道上皮TLR4表达增高,使Th2与Th17淋巴细胞活化,气道内炎症细胞浸润,可能在哮喘气道炎症中起重要作用。 Objective To study the effects of house dust mite (HDM) on Toll-like receptor 4 (TLR4) expression and T lymphocyte differentiation in airway epithelium to further explore its role in airway inflammation in asthmatic mice. Methods Thirty female BALB / c mice were randomly divided into OVA asthma model group (OVA group), HDM group and saline control group (control group). The OVA group was sensitized and challenged with ovalbumin (OVA) to establish a mouse asthma model. The HDM group was given HDM extract instead of the OVA sensitization and challenge, while the control group was replaced by OVA. The pathological inflammatory infiltration of airway and lung tissue were observed in mice, and the total number of cells and the number of cells in bronchoalveolar lavage fluid (BALF) were counted. The contents of IL-4, IL-5, IL-13, IFN-γ and IL-17 in BALF supernatant of mice were detected by ELISA. The expression of TLR4 mRNA in airway epithelium was detected by real - time fluorescence quantitative PCR and the expression of TLR4 protein in airway epithelium was detected by immunoblotting. Flow cytometry was used to detect the percentage of Th1, Th2 and Th17 lymphocytes in CD4 + T lymphocytes in peripheral blood of mice. Results The bronchial submucosal edema, mucinous gland hyperplasia and inflammatory cell infiltration in eosinophils of OVA group were infiltrated. The infiltration of inflammatory cells such as alveolar space and interstitial hyperemia and neutrophil appeared in HDM group. In control group, No thickening, no inflammatory cell infiltration, alveolar wall integrity. Compared with the OVA group, the total number of BALF cells in the HDM group and the number of the classification group were significantly higher than those in the eosinophils group (P <0.05), and the others were significantly increased (P <0.05) (P <0.05). The expression of TLR4 mRNA and TLR4 protein in airway epithelium of HDM group were significantly higher than those in OVA group (P <0.05) (P <0.05). There was no significant difference between OVA group and control group (P> 0.05). Compared with OVA group, the levels of Th2 and Th17 in peripheral blood of HDM group were significantly increased (P <0.05), while there was no significant change in Th1 cells (P> 0.05). Conclusion HDM induces the up-regulation of TLR4 in airway epithelium, activates Th2 and Th17 lymphocytes, and inflammatory cell infiltration in the airway may play an important role in the airway inflammation of asthma.