钾通道阻滞剂对大鼠支气管平滑肌细胞增殖的影响

目的探讨电压依赖性延迟整流钾通道(K_V)、Ca²⁺激活钾通道(K_Ca)和ATP敏感性钾通道(K_ATP)对大鼠支气管平滑肌细胞(BSMC)增殖的影响。 方法应用免疫细胞化学、MTT微量比色分析法及流式细胞术,观察K_V,K_Ca和K_ATP对培养中大鼠BSMC增殖的影响。结果K_V阻断剂4-氨基吡啶(4-AP)显著促进大鼠BSMC增殖细胞核抗原的表达,提高BSMC吸光度值,使S+G₂M期细胞数显著增多,并显著提高基础状态下BSMC内Ca²⁺浓度,而K_Ca阻断剂四乙铵(TEA)和K_ATP阻断剂格列本脲(Glib)均无此效应。 结论大鼠BSMC K_V活性的抑制,可提高细胞内Ca²⁺浓度,促进细胞的增殖,而K_Ca和K_ATP对BSMC的增殖均无明显影响。

Effects of potassium channel blockers on the proliferation of rat bronchial smooth muscle cells

Aim To investigate the effects of blockers of the three kinds of potassium channels: voltage dependent K + channel(K V), calcium activated K + channel(K Ca ) and ATP sensitive K + channel(K ATP ), on the proliferation of rat bronchial smooth muscle cells (BSMCs). Methods The effects of three kinds of potassium channel blockers on the proliferation of BSMCs were detected by MTT method, immunocytochemistry staining and flow cytometry. Their effects on the dynamic changes of Ca 2+ concentration in BSMCs were investigated by the fluorophotometry of Fura 2/AM. Results The K V blocker 4 aminopyridine (4 AP) was shown to significantly increase the expression of proliferating cell nucleus antigen in cultured rat BSMCs ( P <0 01), but the K Ca blocker tetraethylammonium (TEA) and K ATP blocker glibenclamide(Glib) did not show such effect ( P >0 05). 4 AP was found to significantly increase the optical density value of the cultured BSMCs ( P <0 01) by MTT method and the numbers of S+G 2M BSMCs( P <0 05) by flow cytometry. TEA and Glib did not show such effects. 4 AP significantly increased the Ca 2+ concentration in cultured BSMCs( P <0 01). TEA and Glib did not show such effects. Conclusion This result suggests that inhibition of K V activity can increase intracellular Ca 2+ and proliferation of rat BSMCs, but inhibition of K Ca and K ATP showed no effect.