慢性吸烟大鼠肺动脉平滑肌细胞钾通道Kv1.5、BKCa表达的变化

目的：观察吸烟对大鼠肺动脉平滑肌大电导的钙激活的钾通道（BK_Ca）和电压依赖性延迟整流钾通道Kv1.5蛋白和mRNA表达的影响，以阐明吸烟引起的肺血管反应性改变中钾通道表达的变化。方法：复制大鼠的慢性吸烟模型，采用HE染色、免疫组织化学染色、原位杂交等方法。结果：（1）慢性吸烟可降低大鼠肺动脉平滑肌 BK_Ca 蛋白和mRNA表达；（2）慢性吸烟可降低大鼠肺动脉平滑肌Kv1.5蛋白和mRNA表达；（3）大动脉 BK_Ca的降低程度大于Kv1.5，小动脉 BK_Ca和Kv1.5的降低程度无明显差异。结论：慢性吸烟可下调大鼠肺动脉平滑肌钾通道 BK_Ca和Kv1.5的表达水平，是导致肺血管反应性增高的机制之一。

Effect of chronic cigarette smoking on BKCa and Kv1.5 expression in rat pulmonary arterial smooth muscle cells

AIM:To investigate the role of potassium channel expression alteration in chronic cigarette smoking-induced increase in pulmonary vascular responsiveness,the effect of chronic cigarette smoking on large-conductance calcium-activated potassium channel(BKCa) and voltage-dependent delayed rectifier potassium channel(Kv1.5) expression in rat pulmonary smooth muscle cells were investigated in vivo.METHODS: HE staining,immuno-histochemistry and in situ hybridization techniques were used.RESULTS:(1) Chronic cigarette smoking downregulates the protein and mRNA expression of BKCa in pulmonary arterial smooth muscles.(2) Chronic cigarette smoking downregulated the protein and mRNA expression of Kv1.5 in pulmonary arterial smooth muscles.(3) In big artery,BKCa decreased more makedly than Kv1.5,but in small artery,both of them decreased equally.CONCLUSION: Chronic cigarette smoking downregulates the levels of BKCa and Kv1.5 in rat pulmonary arterial smooth muscle cells in vivo,which maybe contribute to the mechanism of cigarette smoking-induced increase in pulmonary vascular responsiveness.