流感病毒唾液酸受体在哮喘小鼠气道组织的分布和表达

Expression of influenza virus sialic acid receptors in the airway of asthmatic mice

目的观察对比流感病毒唾液酸a2，3-半乳糖（SAa2，3-gal）和唾液酸a2，6-半乳糖（SAa2，6-gal）受体在哮喘小鼠气道组织中的分布和表达以及地塞米松干预对其表达的影响。方法30只BALB/c小鼠被随机分成正常组（N组）、哮喘组（A组）和地塞米松干预组（D组）。A组小鼠以卵蛋白（OVA）致敏后激发建立哮喘模型，D组激发前腹腔注射地塞米松，余同A组。行BALF细胞计数，ELISA测定BALF中IL-5浓度，HE染色观察肺组织病理学改变及气道炎症评分，AB-PAS染色观察黏液分泌，免疫组化法（IHC）观察肺组织Muc5ac蛋白表达，免疫荧光法观察各组小鼠气道组织中唾液酸受体分布和表达的差异。结果A组小鼠BALF嗜酸性粒细胞数、IL-5浓度、气道炎症评分、气道黏液分泌较N组小鼠均升高，而D组小鼠上述指标较A组降低。SAa2，3-gal和SAa2，6-gal受体在各组气道组织中均有表。SAa2，3-gal受体在哮喘组气道上皮细胞表达的平均阳性率较N组升高，SAa2，3-gal和SAa2，6-gal受体在D组气道上皮细胞分布和表达的平均阳性率均较N组和A组升高（P〈0.05）。结论哮喘组小鼠气道上皮SAa2，3-gal受体的表达增强；地塞米松上调SAa2，3-gal和SAa2，6-gal受体的表达。两者可能是哮喘患者对流感病毒易感性增强的原因之一。

Objective To observe the expression of influenza virus sialic acid receptors （SAa2,3- gal and SAa2,6-gal） and the influence of dexamethasone intervention to its expression in the airway of asthmatic mice. Methods Thirty BALB/c mice were randomly divided into normal group （group N, n = 10） , asthma group （group A, n = 10） and dexamethasone intervention group （group D, n = 10）. Mice of group A were sensitized and challenged by ovalbumin （OVA） to build asthmatic model. Mice in group D were given dexamethasone （2 mg/kg i. p. ） 30 minutes before challenging, other procedures were the same as those of group A. The levels of IL-5 in the brochoalveolar lavage fluid （BALF） of mice in each group were determined by ELISA, the pathological changes of lung tissues were observed by HE staining, the degree of mucus secretion in airways were observed by AB-PAS staining, the expression of MucinSac （MucSac） in lung tissues were observed by immunohistochemical （IHC） staining, the expression of virus sialic acid receptors were observed by immunofluorescence. Results The counts of eosinophiis, the level of IL-5 in BALF, the airway inflammatory pathological scores, the degree of mucus secretion, the expression of Muc5ac protein of group A were higher than those in group N and D （ P 〈 0.05 ）. Receptors of SA a2,3-gal and SA a 2,6-gal were expressed in all groups （ P 〈 0.05 ）. The average positive rate for SA a 2,3-gal receptor in group A were higher than that in group N. The average positive rate for SA a 2,3-gal and SA a 2,6-gal receptor in group D were higher than those of group N and A （P 〈 0.05）. Conclusion All these results indicate that the high expression of influenza virus sialic acid receptors due to asthma and dexamethasone intervention may be the mechanism of the enhanced susceptibility to influenza virus of asthma patients.