Mont Meghan R, Carlson C George, Geisbuhler Timothy P
Department of Physiology, A.T. Still University of Health Sciences, 800 West Jefferson Street, Kirksville College of Osteopathic Medicine, Kirksville, MO 63501, USA.
Can J Physiol Pharmacol. 2009 May;87(5):360-70. doi: 10.1139/y09-020.
Calcium has been proposed as a primary influence on cell death during ischemic episodes in myocardial cells. One component of calcium entry into a cell is resting calcium influx. This basal movement of calcium is blocked by 100 micromol/L gadolinium chloride (GdCl3) in cardiac myocytes. Therefore, GdCl3 should be cardioprotective under anoxic conditions. To test this, cardiac myocytes isolated from adult male rats were subjected to anoxia (100% N2) in the presence or absence of 100 micromol/L GdCl3 in one of 2 ways. In the first method, cells were suspended in media and rendered anoxic for 0, 30, and 60 min, after which cell morphology and viability were scored. After 60 min of anoxia, rod-shaped cells accounted for 46% +/- 4% of total cells (viability 81%); 10 min of reoxygenation markedly reduced rod-shaped cells to 27% (viability 72%). GdCl3 in the medium did not protect the cells (anoxic rods 49%, reoxygenated rods 30%, viability 77%). In the second method, cells were attached to a laminin substrate, rendered anoxic, and then videotaped for up to 6 h. In this system, cells maintained their shape for some time after the onset of anoxia, and then began to 'die' (i.e., to take on either a rigor form or hypercontracted form) at a measurable rate. Time to onset of 'death' (t0), time to 50% and 100% 'death' (t50 and t100), and rate of 'death' were used to measure anoxic damage. Without GdCl3, cells on average began to die 115 +/- 32 min after the onset of anoxia (t0); they died at an average rate of 0.046 cells/min. t50 was achieved in 149 +/- 42 min, t100 in 183 +/- 54 min. Addition of 100 micromol/L GdCl3 did not affect any of these parameters. We concluded that GdCl3 was not cardioprotective for anoxic myocytes and that cell damage generated by anoxia could not be attributed to resting calcium influx.
钙被认为是心肌细胞缺血发作期间细胞死亡的主要影响因素。钙进入细胞的一个组成部分是静息钙内流。心肌细胞中钙的这种基础运动可被100微摩尔/升的氯化钆（GdCl3）阻断。因此，GdCl3在缺氧条件下应具有心脏保护作用。为了验证这一点，以两种方式之一，将从成年雄性大鼠分离的心肌细胞在有或无100微摩尔/升GdCl3的情况下置于缺氧环境（100%氮气）中。在第一种方法中，将细胞悬浮在培养基中，使其缺氧0、30和60分钟，之后对细胞形态和活力进行评分。缺氧60分钟后，杆状细胞占总细胞的46%±4%（活力81%）；复氧10分钟后，杆状细胞明显减少至27%（活力72%）。培养基中的GdCl3并未保护细胞（缺氧后杆状细胞49%，复氧后杆状细胞30%，活力77%）。在第二种方法中，将细胞附着在层粘连蛋白底物上，使其缺氧，然后录像长达6小时。在这个系统中，细胞在缺氧开始后一段时间内保持其形状，然后开始以可测量的速率“死亡”（即呈现僵硬形式或过度收缩形式）。“死亡”开始时间（t0）、50%和100%“死亡”时间（t50和t100）以及“死亡”速率用于衡量缺氧损伤。在没有GdCl3的情况下，细胞在缺氧开始后平均115±32分钟开始死亡（t0）；它们的平均死亡速率为0.046个细胞/分钟。t50在149±42分钟达到，t100在183±54分钟达到。添加100微摩尔/升GdCl3对这些参数均无影响。我们得出结论，GdCl3对缺氧心肌细胞没有心脏保护作用，并且缺氧产生的细胞损伤不能归因于静息钙内流。
