沙丁胺醇对大鼠支气管平滑肌细胞容量性钙内流的影响

目的:观察沙丁胺醇对正常和IL-13刺激的大鼠支气管平滑肌细胞(rBSMC)胞质Ca2+信号的影响,探讨沙丁胺醇治疗哮喘的作用机制。方法:体外培养大鼠支气管平滑肌细胞,利用共聚焦显微镜测定胞质Ca2+水平,观察沙丁胺醇作用后正常和IL-13刺激后的rBSMC的钙池Ca2+释放和容量性Ca2+内流(CCE)的变化。结果:IL-13 10μg/L处理24 h后,rASMC的Ca2+释放和Ca2+内流均高于正常对照组;10μmol/L沙丁胺醇不影响正常rASMC的Ca2+释放,但是显著抑制CCE;10μmol/L沙丁胺醇对IL-13刺激后的Ca2+释放和CCE的上升均有抑制作用。结论:沙丁胺醇可以抑制Th2细胞因子刺激后的气道平滑肌细胞的容量性Ca2+内流,从而降低胞质Ca2+水平。提示容量性CCE在气道高反应性的发生以及beta 2受体激动剂的治疗效应中具有重要作用。

Effects of Saibutamol on Capacitative Calcium Entry of Rat Bronchial Smooth Muscle Cells

Objective:To investigate the effects of beta 2 receptor agonist salbutamol on cytoplasmic Ca2+ levels of rat bronchial smooth muscle cells(rBSMCs) stimulated with Th2 cytokine IL-13.Methods:The cytoplasmic Ca2+ levels of in vitro cultured rBSMCs were measured with Fluo-3-AM by confocal microscopy system.The changes of Ca2+ release and capacitative Ca2+ entry(CCE) of control and IL-13 groups treated with salbutamol were observed.Results:Ca2+ release and CCE in IL-13 pretreated cells were significantly higher than those of untreated control cells;Salbutamol at 10 μmol/L significantly inhibited CCE both in control and in IL-13 pretreated cells;Salbutamol also decreased Ca2+ release in IL-13 pretreated cells but not in control cells.Conclusion:Salbutamol can reverse the enhanced CCE stimulated by IL-13 via inhibiting capacitative calcium entry.CCE might be an important therapeutic target of airway hyperreactivity in asthma.