[Correlation of eosinophil apoptosis with interleukin 5 mRNA expression in lung tissues of asthmatic guinea pigs].

OBJECTIVE: To explore the correlation of interleukin 5 mRNA expression with eosinophil apoptosis in lung tissues of asthmatic guinea pigs. METHODS: Guinea pigs were divided into asthma, asthma pretreated with dexamethasone and control groups. Guinea pigs were sensitized by exposure to aerosolized ovalbumin. Twenty four hours after the animals were challenged by aerosolized ovalbumin, the apoptosis percentages of hypodense eosinophils(HEo) and normodense eosinophils(NEo) in bronchoalveolar lavage fluid (BALF), and IL-5 mRNA expression in lung tissues were detected with terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) technique and in situ hybridization. RESULTS: (1) In the asthmatic group, the percentages of HEo and NEo apoptosis were significantly decreased (P < 0.05), and IL-5 mRNA expression was significantly increased as compared with the control (P < 0.01). (2) In the group pretreated with dexamethasone, the apoptosis percentages of HEo and NEo were significantly increased (P < 0.01), and IL-5 mRNA expression was reduced as compared with the asthmatic group (P < 0.01). (3) IL-5 mRNA expression was negatively correlated with apoptosis percentage of HEo (r = -0.491, P < 0.05) and NEo (r = -0.492, P < 0.05). CONCLUSIONS: IL-5 mRNA expression in lung tissues closely correlated with apoptosis percentage of Eos in BALF. Inhibiting the expression of IL-5 mRNA and promoting the apoptosis of Eos in lung tissues may be one of the important mechanisms of glucocorticoids to reduce infiltration of Eos in lung tissues and their therapeutic effect in asthma.