Effects of Dexamethasone on expression of Fas mRNA and apoptosis in eosinophils

Objective:To investigate the effects of Dexamethasone(DM) on expression of Fas mRNA and apoptosis in eosinophils(Eos) of bronchoalveolar lavage fluid(BALF) in asthmatic guinea pigs,and to discuss the mechanism of DM promoting Eos apoptosis.Methods: After guinea pigs were stimulated by ovalbumin(OA) for 48 hours,hypodense Eos(HEos) and normodense Eos(NEos) were purified from BALF by gradients of percoll.Purified Eos cells were incubated with different concentration of DM(10-10to 10-5mol/L) in RPMI 1640 medium for 24 hours.The expression of Fas mRNA in Eos was measured by hybridization,and the apoptosis was detected by TUNEL assay.Results:After Eos cells were cultured under the condition of DM administration in vitro,apoptotic Eos increased and the expression of Fas mRNA increased in a dose-dependent manner.The expression of Fas mRNA was correlated with Eos apoptosis.Conclusion: DM can promote Eos apoptosis and the expression of Fas mRNA in dose-dependent manner in vitro.Overexpression of Fas might be one of the mechanisms that DM promotes apoptosis of Eos.