囊性纤维化跨膜传导调节体氯离子通道对大鼠肺泡液体清除率的影响

The Effects of Cystic Fibrosis Transmembrance Conductance Regulator Inhibitors on Rat Alveolar Fluid Clearance

目的探讨囊性纤维化跨膜传导调节体(Cystic fibrosis transmembrance conductance regulator,CFTR)氯离子通道在肺泡液体清除过程中的作用及其影响机制。方法5%清蛋白等渗氯化钠溶液和不同药物混合后灌注到离体大鼠的肺泡腔内,根据灌注前及其孵育1 h后清蛋白浓度的变化来计算大鼠肺泡液体清除率(AFC)。结果对照组大鼠基础AFC为(8.16%±1.50%),β1-肾上腺素受体激动剂地诺帕明显著提高AFC,差异有统计学意义(P<0.001)。阿替洛尔(选择性β1-肾上腺素受体阻滞剂)可以完全抑制地诺帕明提高AFC的作用,AFC为(7.78%±2.26%)。两种CFTR的抑制剂格列苯脲和CFTRinh-172可以部分抑制地诺帕明引起的AFC的提高,AFC分别为(10.71%±0.95%)和(12.96%±1.08%),与地诺帕明组比较差异均有统计学意义(P<0.05)。CFTR氯离子通道的开放剂NS004可以提高AFC,与对照组比较差异有统计学意义(P<0.05),钠离子通道的抑制剂氨氯吡咪和格列苯脲及CFTRinh-172可以完全抑制NS004提高AFC的作用,AFC分别为(7.48%±1.16%)、(7.98%±2.13%)和(7.56%±1.02%),与NS004组比较差异有统计学意义(P<0.001)。同时氨氯吡咪可以完全阻断地诺帕明提高AFC的作用,AFC为(8.04%±1.85%),与地诺帕明组比较差异有统计学意义(P<0.001)。结论地诺帕明和NS004可以提高离体大鼠的AFC。两种CFTR的抑制剂格列苯脲和CFTRinh-172可以部分抑制地诺帕明对AFC的提高作用、完全抑制NS004对于AFC的提高作用。氨氯吡咪可以完全阻断地诺帕明对AFC的提高作用。地诺帕明对AFC的提高作用部分是通过CFTR氯离子通道调节的,CFTR氯通道的开放剂NS004对于AFC的调节作用是通过钠离子通道完成的。

Objective To determine the effects of cystic fibrosis transmembrance conductance regulator(CFTR) on alveolar fluid clearance(AFC) and its mechanisms,to find out whether both CFTR inhibitors,glibenclamide and CFTRinh-172,would block the effects of denopamine(a β1-adrenergic agonist) on AFC in isolated rat lungs.Methods Isotonic 5% albumin solutions with different pharmacological agents were instilled into the distal airways in the isolated rat lungs.The lungs were inflated with 100% oxygen at 7 cm H2O and placed in a humid incubator at 37 ℃.AFC was estimated by the progressive increases in the albumin concentration over 1 h.Results Basal AFC was(8.16%±1.50%).Denopamine increased AFC significantly,which was(17.65%±3.71%),2.16 times of basal AFC.There was significant difference between two groups(P<0.001).Atenolol(a β1-adrenergic antagonist) inhibited completely the effects of denopamine,AFC was(7.78%±2.26%).Both CFTR inhibitors,glibenclamide and CFTRinh-172,inhibited partly the effects of denopamine,AFC were(10.71%±0.95%) and(12.96%±1.08%) respectively(P<0.05).NS004,an opener of CFTR,increased AFC significantly,AFC was(13.82%±1.20%)(P<0.05).Amiloride,an inhibitor of Na+ channel,and glibenclamide or CFTRinh-172,CFTR inhibitors,prevented NS004 completely from increasing AFC,AFC were(7.48%±1.16%),(7.98%±2.13%) and(7.56%±1.02%) respectively.And there was significant difference between it and NS004 group(P<0.05).Amiloride was also destructive to the effects of denopamine,AFC was(8.04%±1.85%)(P<0.001).There was significant difference between it and denopamine group(P<0.001).Conclusion Both denopamine and NS004 are potent stimulators on AFC in the rat lungs.Both glibenclamide and CFTRinh-172,CFTR inhibitors,inhibit partly the effects of denopamine and completely the effects of NS004.Amiloride can abolish the effects of denopamine.The effects of denopamine may be partly mediated by CFTR and the effects of NS004 by Na^+ channel.