Influences of dexamethasone on expression of fas, bcl-2 mRNA and apoptosis in eosinophils in vitro

AIM: To investigate the effects of dexamethasone (DM) on expression of fas and bcl-2 mRNA and apoptosis in eosinophils (Eos) of bronchoalveolar lavage fluid (BALF) in asthmatic guinea pig. METHODS: The guineas pigs were stimulated with ovalbumin (OVA) for 48 hours. Hypodense Eos (HEos) and normodense Eos (NEos) were purified from BALF by gradients of Percoll. Eos was cultured in PRMI-1640 medium and DM (10 -10-10 -5 mol/L) was added. The mRNA of fas and bcl-2 in Eos was measured by hybridization. Apoptosis was detected by TdT-mediated dUTP nick end labeling (TUNEL). RESULTS: Eos was cultured under the condition of DM administration in vitro. Apoptotic Eos increased, fas mRNA expression increased and the bcl-2 mRNA expression decreased in a dose-dependent manner. There was significant correlation between Eos apoptosis and fas mRNA expression. The expression of bcl-2 mRNA was inversely correlated with Eos apoptosis. CONCLUSION: DM promoted Eos apoptosis, increased expression of fas and inhibited expression of bcl-2 in a dose-dependent manner in vitro. fas and bcl-2 might be one of mechanisms of DM promoting apoptosis in Eos.