班布特罗对哮喘豚鼠气道嗜酸性粒细胞炎症的作用机理研究

Effect of Bambuterol on Eosinophilic Inflammation of Airway in Asthmatic Guinea Pigs and Its Mechanism

卵白蛋白致敏(OA)建立豚鼠哮喘模型,用不同剂量的班布特罗(Bam)灌胃,密度梯度离心法分离支气管肺泡灌洗液(BALF)中低密度嗜酸性粒细胞(HEos)和正常密度嗜酸性粒细胞(NEos),原位末端标记法(TUNEL)检测嗜酸性粒细胞(Eos)凋亡,酶联免疫吸附(ELISA)法测定BALF中嗜酸性粒细胞趋化因子(Eotaxin)水平。结果表明:15、30mg·kg-1Bam可明显降低BALF中Eos数量和Eotaxin水平,但对Eos凋亡无影响。β-受体阻断剂普萘洛尔可阻断其作用,说明一定剂量的Bam可能通过抑制Eotaxin对Eos的选择性趋化作用降低BALF中Eos的数量,从而发挥对气道炎症的拮抗作用。

An asthmatic model of guinea pigs was established by sensisizing with ovalbumin. Different doses of bambuterol were administered to guinea pigs by intragastric gavage (ig). Hypodense eosinophils and normodense eosinophils in bronchoalveolar lavage fluid (BALF) were purified by density gradient centrifugation. Apoptosis of eosinophils was determined by TdT-mediated dUTP nick end labeling (TUNEL). The level of eosinophil chemotaxin (eotaxin) in BALF was measured by enzyme-linked immunosorbent assay (ELISA). The results showed that bambuterol at the dose of 15 and 30 mg·kg^(-1)decreased the number of eosinophils and the level of eotaxin in BALF significantly, while there was no effect on apoptosis of eosinophils. These effects were completely inhibited by pretreatment with propranolol. These results demonstrated that decreasing the number of eosinophils in BALF by inhibiting selective chemotaxis of eotaxin to eosinophils may be one of the mechanisms for bambuterol to antagonize airway inflammation.