Pharmacological activation of mitochondrial BKCa channels protects isolated cardiomyocytes against simulated reperfusion-induced injury
Pharmacological activation of mitochondrial BKCa channels protects isolated cardiomyocytes against simulated reperfusion-induced injury
复制标题
DOI：
10.1177/1535370212474596
复制
发表时间：
2013-02-01
影响因子：
3.2
通讯作者：
Kolar, Frantisek
中科院分区：
文献类型：
--
作者：
Borchert, Gudrun H.;Hlavackova, Marketa;Kolar, Frantisek
本研究旨在探讨线粒体大电导钙激活钾通道（BKCa）开放对模拟缺血再灌注损伤心肌细胞的保护作用。本研究还旨在确定保护机制是否涉及活性氧（ROS）和磷脂酰肌醇-3-激酶（PI 3 K）的信号转导。我们使用分离的心室肌细胞，这被认为是不包含功能性BKCa通道的肌膜。从成年雄性Wistar大鼠的左心室中分离细胞，并用NaCN和2-脱氧葡萄糖进行25分钟的代谢抑制，然后进行30分钟的再灌注。新型BKCa通道开放剂NS 11021（0.1 μ mol/L）或重新通电时添加过氧化氢（2 μ mol/L），可增加细胞存活率（棒状细胞数量）并显着减少乳酸脱氢酶（LDH）的释放。这些细胞保护作用的NS 11021被完全废除paxilline，BKCa抑制剂，或tempol，抗氧化剂，但不是渥曼青霉素，PI 3 K的抑制剂。NS 11021轻微但显著地增加了2 '7'-二氯二氢荧光素二乙酸酯（DCF-DA）负载的肌细胞中的荧光信号，表明ROS形成增加。NS 11021诱导的ROS形成被paxilline或tempol消除。NS 13558（0.1 μ mol/L）是NS 11021的无活性结构类似物，既不影响细胞存活/LDH释放，也不影响DCF-DA荧光。这些结果表明，药理学激活线粒体！BKCa通道有效地保护分离的心肌细胞免受与模拟再灌注相关的损伤。这种形式的保护机制需要ROS信号传导，但不需要PI 3 K通路的激活。
The aim of this study was to find out whether opening of mitochondrial large-conductance Ca2+-activated potassium channels (BKCa) protects cardiomyocytes against injury caused by simulated ischemia and reperfusion. This study also aimed to determine whether the protective mechanism involves signaling by reactive oxygen species (ROS) and phosphatidylinositol-3-kinase (PI3K). We used isolated ventricular myocytes, which are believed to contain no functional BKCa channels in the sarcolemma. Cells were isolated from the left ventricles of adult male Wistar rats and subjected to 25-min metabolic inhibition with NaCN and 2-deoxyglucose followed by 30-min re-energization. NS11021 (0.1 mu mol/L), a novel BKCa channel opener, or hydrogen peroxide (2 mu mol/L) added at re-energization, increased cell survival (the number of rod-shaped cells) and markedly reduced the release of lactate dehydrogenase (LDH). These cytoprotective effects of NS11021 were completely abolished by paxilline, a BKCa inhibitor, or tempol, an antioxidant, but not by wortmannin, an inhibitor of PI3K. NS11021 slightly but significantly increased the fluorescence signal in 2'7'-dichlorodihydrofluorescein diacetate (DCF-DA)-loaded myocytes, indicating an increased ROS formation. The NS11021-induced ROS formation was abolished by paxilline or tempol. NS13558 (0.1 mu mol/L), an inactive structural analogue of NS11021, affected neither cell survival/LDH release nor DCF-DA fluorescence. These results suggest that pharmacological activation of mitochondria! BKCa channels effectively protects isolated cardiomyocytes against injury associated with simulated reperfusion. The mechanism for this form of protection requires ROS signaling, but not the activation of the PI3K pathway.