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.