急性缺氧对环匹阿尼酸诱导的大鼠远端肺静脉平滑肌细胞内钙浓度升高的影响

Effect of Acute Hypoxia on Cyclopiazonic Acid Induced Intracellular Calcium Cation Enhancement in Rat Distal Pulmonary Venous Smooth Muscle Cells

目的：研究急性缺氧对Ca2＋-ATPase抑制剂——环匹阿尼酸（CPA）诱导的大鼠远端肺静脉平滑肌细胞（PVSMC）内钙浓度（[Ca2＋]i）升高的影响及机制。方法：选用6只雄性SD大鼠（体重200~250 g）,培养大鼠PVSMC,运用荧光显微镜和细胞内钙浓度检测系统观测CPA及急性缺氧（4%O2）对PVSMC的[Ca2＋]i影响及钙池操纵性钙通道（SOCC）阻断剂氯化镍（Ni Cl2）和SKF96365的干预作用。结果：含5μmol/L硝苯地平（电压依赖钙通道阻断剂）的无钙Krebs溶液孵育PVSMC,10μmol/L CPA使PVSMC的[Ca2＋]i小幅度升高,急性缺氧能使[Ca2＋]i升高幅度增加;恢复细胞外Ca2＋至2.5 mmol/L后,10μmol/L CPA使[Ca2＋]i显著升高,急性缺氧可导致CPA诱导的[Ca2＋]i升高显著增强;SOCC阻断剂Ni Cl2（500μmol/L）和SKF96365（50μmol/L）均能明显抑制急性缺氧条件下CPA诱导的[Ca2＋]i升高,但对高钾（60 mmol/L KCl）Krebs溶液引起的[Ca2＋]i反应无影响。结论：急性缺氧能够使CPA诱导的大鼠远端PVSMC的[Ca2＋]i升高增强,[Ca2＋]i升高可被SOCC阻断剂阻断,提示急性缺氧能够增强SOCC活性,使细胞外Ca2＋通过SOCC内流增强,从而导致大鼠远端PVSMC的[Ca2＋]i升高。

Objective： To study the effect and the mechanism of acute hypoxia on CaZ＋-ATPase inhibitor, cyclopiazonic acid （CPA） induced intracellular calcium cation enhancement in rat distal pulmonary venous smooth muscle cells （PVSMC）. Methods： The PVSMC were isolated from 6 male SD rats and the cells were cultured for further experiment. Enhancing effects of CPA, acute hypoxia （4% O2） on [Ca^2＋]i in distal PVSMC and the interventional effects of 2 store-operated Ca^2＋ channels （SOCC） inhibitors, NiCl2 and SKF96365 on [Ca^2＋]i in distal PVSMC were tested by fluorescence microscope and intraeellular [Ca2＋] examining system. Results： When PVSMC were perfused with Ca^2＋-free Krebs solution containing 5 μmol/L nifedipine, 10 μmol/L CPA caused a slight elevation of [Ca2＋]i, and acute hypoxia obviously enhanced the [Ca2＋]i in PVSMC. When restoration of extracellular [Ca2＋] to 2.5 mmol/L, 10 μmol/L CPA caused significant elevation of [Ca2＋]i, and acute hypoxia obviously enhanced [Ca2^＋]i induced by CPA in PVSMC. The SOCC inhibitors, NiCI2 （500 μmol/L） and SKF96365 （50 μmol/L） distinctively attenuated the elevation of [Ca^2＋]iby hypoxia and CPA. However, NiCl2 and SKF96365 had no effect on highpotassium （60 mmol/L KCl Krebs solution） induced elevation of [Ca^2＋]i in distal PVSMC. Conclusion： Acute hypoxia enhanced the elevation of [Ca^2＋]i induced by CPA; such effect could be selectively blocked by SOCC inhibitor which indicated that acute hypoxia could enhance the activity of SOCC in rat distal PVSMC.