辛夷對於卵白蛋白敏感化Brown Norway大鼠之抗氣喘作用

Anti-asthmatic Effects of Magnoliae Flos in Ovalbumin-sensitized Brown Norway Rats

氣喘是一種慢性呼吸道發炎反應，也是世界上常見的慢性健康問題。本研究藉由氣喘之動物模式評估辛夷的抗氣喘作用。本實驗採以卵白蛋白敏感化之Brown Norway大鼠為氣喘動物模式，並與生理食鹽水處理之Brown Norway大鼠做為對照組。卵白蛋白敏感化的Brown Norway大鼠再隨機分成三組，分別連續五天給予餵食低劑量（3 g/kg）辛夷、高劑量（10 g/kg）辛夷或蒸餾水。為了評估呼吸道過度反應，以靜脈注射支氣管平滑肌收縮劑methacholine（3，10，30 μg/kg），測量動物的總肺阻力與動態肺順應性。另外亦評估呼吸道發炎狀況，藉由測量支氣管肺泡沖洗液的發炎細胞、細胞激素（IL-6，IL-13）濃度與血漿IgE濃度。實驗顯示以卵白蛋白敏感化之Brown Norway大鼠可引發呼吸道過度反應與呼吸道發炎細胞浸潤作用（包括：嗜酸白血球、嗜中白血球、嗜鹼白血球、淋巴球與巨噬細胞數目增加）。相反地，卵白蛋白敏感化之大鼠其支氣管肺泡沖洗液中細胞激素IL-6，IL-13濃度與血漿IgE濃度與對照組相比較並無明顯差異。再者，餵食辛夷後可降低卵白蛋白敏感化引起之呼吸道過度反應，而且具有抑制嗜酸白血球與淋巴球發炎細胞浸潤作用，上述之抑制作用具有劑量—反應間之關係。實驗結顯示辛夷對卵白蛋白敏感化的氣喘模式動物具有潛在性的治療作用。

Asthma is a chronic respiratory inflammatory disease that is common public health problem in the world. To date, long-term administration of steroid has been developed for the treatment of asthma although their use is limited by numerous adverse side effects. Magnoliae flos is used in traditional Chinese medicine for treatment of various allergic diseases, including nasal congestion, sinusitis, and allergic rhinitis. Previous study demonstrated magnoliae flos attenuates immediate-type allergic reactions by inhibition of mast cell degranulation both in vivo and in vitro. However, its effect in experiment asthmatic models remains to be investigated. In this study, we evaluated the anti-asthmatic effects of magnoliae flos in ovalbumin (OVA)-sensitized Brown Norway (BN) rats. To accomplish this objective, we used male adult BN rats sensitized with OVA and matching control animals (receiving saline vehicle). Furthermore, the OVA-sensitized rats were randomized into three groups and treated with 3 g/kg magnoliae flos, 10 g/kg magnoliae flos, and vehicle by oral administration for 5 consecutive days. To evaluate airway hyperresponsiveness (e.g. total lung resistance and dynamic lung compliance) to bolus intravenous injection of methacholine (3, 10, 30 μg/kg) were measured in each animal. In addition, to examine airway inflammation, the levels of various inflammatory cells in bronchoalveolar lavage fluid (BALF), serum IgE, and levels of cytokine (e.g. IL-6 and IL-13) in BALF were assessed. Our data showed that OVA sensitization induced airway hyperresponsiveness and infiltration of inflammatory cells (e.g. eosinophil, neutrophil, basophil, lymphocyte, macrophage) in rats. In contrast, OVA sensitization did not significantly increase the levels of IL-6 and IL-13 in BALF and serum IgE. Oral administration of magnoliae flos dose-dependently decreased airway hyperresponsiveness as well as infiltration of eosinophil and lymphocyte in OVA-sensitized rats. Taken together, these data indicated that magnoliae flos may have potential therapeutic value on an OVA-sensitized animal model of allergic asthma.