地塞米松对哮喘豚鼠嗜酸细胞凋亡及bcl—2 mRNA表达的影响

目的 观察地塞米松（DM）对哮喘豚鼠体外不同密度的嗜酸性粒细胞（Eos)凋亡及bcl-2表达的影响，并探讨激素促进哮喘Eos凋亡的机制。方法 以卵蛋白激发哮喘豚鼠模型48h后，进行支气管肺泡灌洗，分离灌洗液中不同密度的Eos。加入DM（10^10-10^5mol/L），以原位杂交法检测Eos的bcl-2表达，TUNEL法检测Eos的凋亡。结果 DM干预24h，可见Eos凋亡增加，bcl-2 mRNA表达降低，且呈剂量依赖性。bcl-2 mRNA的表达与Eos凋亡呈负相关。结论 DM可抑制bcl-2的表达，促进Eos凋亡。bcl-2表达的减少可能是DM调节Eos凋亡的机制之一。

The effects of dexamethasone on expression of bcl-2 mRNA and apoptosis in eosinophils of asthmatic guinea pig

Aim To investigate the effect of dexamethasone ( DM) on expression of bcl-2 mRNA and apoptosis of eosinophils( Eos) in bronchoalveolar lavage fluid ( BALF) from asthmatic guinea pig, and mechanism of Eos apoptosis promoted by steroid. Methods After giunea pig were stimulated with ovalbumin (OVA) for 48 hours, hypodense Eos ( HEos) and normodense Eos ( NEos) were i- solated from BALE by gradient centrifugation with percoll. The Eos cultured in RPMI1640 medium. DM ( 10~(-10)~10 ~(-5) was added to the wells. The expression of bcl -2 mRNA in Los and apoptosis of Eos was detected by in situ hybridization and TdT- mediated dUTP nick end labeling( TUNEL), respectively. Results After 24 hours Culture in the presence of DM, apoptotic Los increased and expres- sion of the bc 1 - 2 mRNA decreased in a dose- dependent manner. The expression of bcl -2 mRNA was correlated negatively with Eos apoptosis. Conclusion DM may promote Eos apoptosis and inhibit expression of bc 1-2 in dose - dependent manner in vitro. Inhibition of bc 1-2 expression might be one of the mechanisms of Eos apopto- sis promoted by DM.