Relationship between pulmonary airway eosinophil infiltration and apoptosis in allergic guinea pigs

doi:10.3969/j.issn.1001-9448.2001.02.003

Abstract：Objective To investigate the relationship between pulmonary airway eosinophil accumulation and apoptosis in a guinea pig model of asthmatic response to ovalbumin inhalation. Methods We have made a detailed examination of histopathology, cytology and apoptosis in the airways up to 7 days after antigen challenge. Apoptosis of eosinophils was measured by using in situ tailing technique. We also observed the changes of eosinophils apoptosis in lung after treatment with dexamethasone. Results Eosinophil migration in bronchus was obvious from 8 h to 24 h following antigen challenge, then declined. Eosinophilia was demonstrable in bronchoalveolar lavage fluid (BALF) and bronchial tissue at 8 h, peaked during 24h to 72h and persisted for at least 7 days. Eosinophilia was accompanied by epithelial damage and subepithelial edema. The percentage of eosinophils apoptosis in BALF of allergic guinea pigs was (2.1±1.3)%, (3.7±2.3)%, and (4.6±2.7)% respectively at 24,48 and 72 h, significantly lower than that of normal control guinea pigs (P＜0.05). The percentage of eosinophils apoptosis significantly increased ［(34.1±12.2）%, P＜0.01］, accompanied by resolution of lung inflammation following treatment with dexamethasone. Conclusion The apoptosis of eosinophils in asthmatic guinea pigs was inhibited, contributing to persistent eosinophilia.