Steigen T K, Myrmel T, Forsdahl K, Larsen T S
Department of Medical Physiology, University of Tromsø, Norway.
Mol Cell Biochem. 1992 Oct 21;116(1-2):47-52. doi: 10.1007/BF01270568.
Myocardial cell vulnerability to phospholipase C (PC-PLC) attack was investigated in three different preparations of rat myocardial cells: triacylglycerol (TG)-loaded, hypothermic/rewarmed and energy depleted myocytes. The attack by PC-PLC was evaluated as PC-PLC induced glycerol output due to the combined action of phospholipase C and intracellular lipases. PC-PLC induced glycerol output was significantly higher (p < 0.05) in all three myocyte preparations, compared to their respective controls. Cell morphology (% rod shaped myocytes) of TG-loaded or hypothermic/rewarmed myocytes was not different from their controls, whereas energy depleted myocytes almost exclusively were rounded up, due to hypercontraction of the myofilaments. Hypothermic/rewarmed and energy depleted myocytes showed a significantly higher release of lactate dehydrogenase (LDH), compared to their controls although the difference was much more pronounced in the latter. Finally, the cellular contents of ATP were maintained both in TG-loaded and hypothermic rewarmed myocytes, while energy depleted myocytes contained only about 25% of the normal ATP level. These results demonstrate that attack from exogenously added phospholipases can occur, not only in seriously damaged cardiac myocytes, but in myocytes with a more subtle damage as well.
在大鼠心肌细胞的三种不同制剂中研究了心肌细胞对磷脂酶C（PC-PLC）攻击的易损性：负载三酰甘油（TG）的、低温/复温的和能量耗尽的心肌细胞。由于磷脂酶C和细胞内脂肪酶的联合作用，PC-PLC的攻击被评估为PC-PLC诱导的甘油输出。与各自的对照相比，在所有三种心肌细胞制剂中，PC-PLC诱导的甘油输出均显著更高（p<0.05）。负载TG或低温/复温的心肌细胞的细胞形态（杆状心肌细胞的百分比）与对照无差异，而能量耗尽的心肌细胞几乎完全呈圆形，这是由于肌丝过度收缩所致。与对照相比，低温/复温的和能量耗尽的心肌细胞显示出乳酸脱氢酶（LDH）的释放显著更高，尽管后者的差异更为明显。最后，负载TG的和低温复温的心肌细胞中的ATP细胞含量均得以维持，而能量耗尽的心肌细胞仅含有正常ATP水平的约25%。这些结果表明，外源性添加的磷脂酶的攻击不仅可以发生在严重受损的心肌细胞中，也可以发生在损伤更细微的心肌细胞中。
