菠萝蛋白酶诱导小鼠急性过敏性气道炎症的作用研究

Group 2 innate lymphoid cells are responsible for bromelain-induced allergic airway inflammation in mice

探讨菠萝蛋白酶诱导小鼠急性过敏性气道炎症中2型固有淋巴细胞(group 2innate lymphoid cell,ILC2)及相关细胞因子的变化及意义。对未致敏BALB/c雌性小鼠在第1天和第3天给予菠萝蛋白酶滴鼻,ELISA检测12h内小鼠肺组织匀浆上清中IL-33变化,5d后处死小鼠,肺组织切片病理观察,瑞氏染色计数BALF中嗜酸性粒细胞含量,流式检测肺组织中ILC2数量变化,ELISA检测BALF中IL-5、IL-13水平。结果显示,菠萝蛋白酶诱导气道上皮细胞产生IL-33,3h时开始,6h时达高峰;菠萝蛋白酶滴鼻小鼠肺组织切片显示大量炎性细胞浸润和杯状细胞黏液分泌增加,BALF中嗜酸性粒细胞比例增加,IL-5和IL-13含量增加,流式检测肺组织中ILC2数量增多。研究表明,菠萝蛋白酶刺激小鼠气道上皮细胞释放IL-33,引起小鼠肺ILC2活化增殖并分泌大量Th2型细胞因子,引起嗜酸性粒细胞浸润等急性过敏性气道炎症表现,提示ILC2促进早期急性过敏性气道炎症的发生。

We aimed to explore the effect of ILC2s in acute allergic airway inflammation induced by bromelain in mice. Naive BALB/c mice were intranasally exposed to bromelain（10 /1g/dose） on day 1 and 3. Kinetic changes in IL-33 level in lung ho- mogenates were analyzed by ELISA after the first challenge. On day 5, BALF and lung tissues were collected. Histological staining of lung tissue sections was used to assess mucus secretion and inflammation. Flow cytometry was employed to count the number of ILC2s in lung tissues. The number of eosinophils in BALF was determined in cytospin preparations stained with Wright-Giemsa. The levels of IL-5 and IL-13 in BALF were analyzed by ELISA. Upon exposure to bromelain, the lung level of IL-33 quickly increased within 3 h, peaking at 6 h. There were marked airway eosinophilia, infiltrating inflammatory cells and mucus hypersecretion in the bromelain group. The content of ILC2s in lung tissue was increased, and the levels of IL-5 and IL- l3 in BALF were highly raised. In conclusion, intranasal administration of bromelain has been shown to induce the proliferation of ILC2s, resulting in lung eosinophilia and mucus hypersecretion, indicating the critical role of ILC2s in the development of a- cute allergic airway inflammation.