咪达唑仑对人肺脏液体清除的作用机制研究

Mechanisms of midazolam on human alveolar fluid clearance

目的探讨咪达唑仑对人肺上皮细胞短路电流的影响,并探讨可能的机制。方法应用尤斯灌流室装置测定H441单层细胞的短路电流。由总电流减去阿米洛利可抑制的电流算得阿米洛利敏感性电流,以用药前H441单层细胞的阿米洛利敏感性电流初始值为100%对照。用100μmol/L咪达唑仑处理H441细胞,在0,15,30,60min 4个时间点提取蛋白用于蛋白印迹法,研究咪达唑仑对细胞外调节蛋白酶(ERK)1/2蛋白磷酸化的影响。结果咪达唑仑能够剂量依赖性抑制H441单层细胞的短路电流,此电流可被阿米洛利抑制;蛋白印迹法结果显示咪达唑仑能够促进ERK1/2蛋白磷酸化。结论咪达唑仑通过抑制人肺上皮细胞阿米洛利敏感性电流而降低肺泡上皮离子转运,其机制可能与其促进ERK1/2蛋白磷酸化有关。临床上对伴有肺水肿的患者应用咪达唑仑时应考虑其可能对肺泡上皮液体清除的影响。

Objective To explore the effects of midazolam on the short-circuit currents in human alveolar epithelial monolayers and study the possible mechanisms.Methods Short-circuit currents were recorded by ussing-chamber setup.Amiloride-sensitive currents are defined as the difference between the total current and the amiloride-resistant current.ERK1/2phosphorylation protein levels are analyzed at 0,15,30 and 60min after administration of 100μmol/L midazolam.Results Midazolam can inhibit the short-circuit currents in H441 monolayers dose-dependently,which can be inhibited by amiloride.Western-blotting analysis shows that midazolam can increase the level of ERK1/2phosphorylation.Conclusion These data demonstrate that midazolam can reduce the alveolar ion transport by inhibiting the amiloride-sensitive currents,possibly by the enhancement of ERK1/2phosphorylation.The effects of alveolar fluid clearance following application of midazolam should be considered clinically when the patient is complicated with lung injury.