毛大丁草抗卵清蛋白诱导的小鼠支气管哮喘作用的活性部位筛选

Screening the Effective Fraction of Gerbera Piloselloides (Linn.) Cass Against Bronchial Asthma Induced by Ovalbumin in Mice

关键词:  毛大丁草  支气管哮喘  卵清蛋白  肺泡灌洗液  活性部位

Key words:  Gerbera piloselloides  bronchial asthma  ovalbumin  bronchoalveolar lavage fluid  effective fraction

摘要:

目的 通过卵清蛋白(ovalbumin，OVA)诱导的支气管哮喘小鼠模型，筛选毛大丁草抗哮喘的活性部位。方法 采用D101大孔吸附树脂法对毛大丁草50%乙醇提取物进行分段富集，依次洗脱得到水、60%乙醇、95%乙醇3个洗脱部位。小鼠通过腹腔注射OVA致敏、雾化吸入OVA激发来复制哮喘动物模型，在激发阶段连续6 d进行灌胃给药治疗。采用行为学评分考察不同部位对哮喘行为学的影响，利用酶联免疫吸附法测定血清、肺泡灌洗液(bronchoalveolar lavage fluid，BALF)中IL-5的浓度和血清免疫球蛋白IgE的浓度，采用HE染色对肺组织进行组织病理学评价。结果 模型组小鼠哮喘症状评分升高，血清中IgE和IL-5的水平显著升高，BALF中IL-5的水平显著升高；与模型组比较，60%乙醇段高剂量组小鼠哮喘症状明显改善，血清中IL-5的水平显著降低，BALF中IL-5的水平也显著降低。结合病理学切片观察，60%乙醇段治疗的小鼠较之模型组小鼠肺泡间隔增厚程度降低，血管周围和支气管周围炎症细胞浸润显著减少。结论 毛大丁草50%乙醇提取物的60%乙醇洗脱部位为其抗哮喘的活性部位，其化学成分主要是酚酸类、黄酮类和香豆素类。

Abstract:

OBJECTIVE To establish an ovalbumin(OVA)-induced bronchial asthma mouse model and screen the effective fraction of Gerbera piloselloides (Linn.) Cass extract against asthma. METHODS The 50% ethanol extract of G. piloselloides was segmented and enriched by D101 macroporous adsorption resin, obtaining three elution fractions regarding water fraction, 60% ethanol fraction and 95% ethanol fraction. The asthma model was established, after the mice being sensitized with OVA solution by intraperitoneal injections, and the mice being challenged through aerosol inhalation of OVA. Mice were treated with corresponding drugs for 6 consecutive days during the OVA excitation phase. The effect of different fractions on behaviors about asthma symptoms was assessed through recording and calculating behavior score, and the concentration of cytokines IL-5 in serum and bronchoalveolar lavage fluid(BALF) and serum immunoglobulin IgE was measured by enzyme linked immunosorbent assay(ELISA). Additionally, histopathological changes of lung tissue were evaluated with HE staining. RESULTS The behavior scores of asthma symptoms and the levels of IgE and IL-5 in serum were significantly raised, and the concentration of IL-5 in BALF was also significantly increased in model group. Compared with model group, the asthma symptoms were significantly improved, and the levels of IgE, IL-5 in serum or BALF were significantly decreased in the mice of 60% ethanol fraction with high-dose group. For histopathological examination, the results showed that the extent of alveolar septal thickening was reduced and the infiltration of inflammatory cells around blood vessels and bronchi was significantly cut down in mice treated with 60% ethanol part relative to mice in the model group. CONCLUSION The 60% ethanol fraction of the 50% ethanol extract from G. piloselloides is the active fraction on treating asthma, in which the major chemical compounds are phenolic acids, flavonoids and coumarins.