地塞米松对哮喘豚鼠嗜酸性粒细胞凋亡及fas、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嗜酸性粒细胞（Eos）凋亡及fas、bcl-2 mRNA表达的影响, 探讨DM促进哮喘Eos凋亡的机制。 方法： 卵蛋白激发哮喘豚鼠动物模型48 h后行支气管肺泡灌洗, 分离低密度及正常密度Eos（HEos,NEos）。HEos及NEos分别与地塞米松（DM）(10^-10-10^-5 mol/L)共培养24 h，以原位杂交方法检测不同Eos的fas及bcl-2 mRNA表达, 3'末端脱氧核苷转移酶介导的脱氧三磷酸尿苷（d-UTP）缺口末端标记（TUNEL）法检测细胞凋亡。 结果： DM干预24 h后，可见Eos细胞凋亡增加的同时，不同密度Eos的 fas mRNA表达也增加，bcl-2 mRNA表达降低，并与DM浓度呈剂量依赖性。fas表达与Eos凋亡呈正相关（P<0.05），而bcl-2的表达与Eos凋亡呈负相关（P<0.05）。 结论： DM可促进不同密度Eos fas表达，抑制其bcl-2表达，促进Eos凋亡。DM可以通过嗜酸性粒细胞fas表达增加及bcl-2表达减少而调节Eos凋亡。

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.