To observe the influences of Dexamethasone(DM)on the apoptosis of eosinophils(Eos)with different densities from asthmatic
guinea pigs in vitro and the
expression of IL-5Rα mRNA in order to explore the
mechanisms of action of DM on the promotion of Eos apoptosis, the Eos with low density (HEos) and normal density (NEos) were isolated from bronchioalveolar lavage fluid (BALF) of the guinea pig asthmatic animal mode stimulated 48 hours previously with ovalbumin (OVA). HEos and NEos were co-cultivated with DM at a concentration of 10-10-10-5 mol/L for 24 hours, the expression of IL-5Rα mRNA was assayed with in situ hybridization, and the Eos apoptosis was detected by TdT-mediated dUTP nick end labeling (TUNEL). The results showed that the expressions of IL-5Rα mRNA in Eos with different densities increased in keeping pace with the increase of the cell apoptosis of Eos in a dose dependent manner after the interference of DM for 24 hours. A positive correlation inter-relationship was found between the expression of IL-5Rα and Eos apoptosis. It suggests that the increased expression of IL-5Rα may be one of the mechanisms for the promotion of Eos apoptosis.