Steenbergen C, Hill M L, Jennings R B
Circ Res. 1985 Dec;57(6):864-75. doi: 10.1161/01.res.57.6.864.
The relationship between cell swelling and plasma membrane disruption has been evaluated in thin myocardial slices incubated in oxygenated or anoxic Krebs-Ringer phosphate media. Electron microscopy and measurements of inulin-diffusible space were used to monitor plasma membrane integrity. Inulin is excluded from the intracellular space of intact cells; therefore, an increase in tissue inulin content is an excellent marker of loss of plasma membrane integrity. Cell volume was increased during exposure of aerobic slices to hypotonic media, but the inulin-diffusible space was not increased and electron micrographs showed no detectable plasma membrane alterations. Likewise, during prolonged anoxic isotonic incubation, no evidence of plasma membrane damage was observed. Incubation in anoxic hypotonic media for 60 minutes resulted in a larger increase in cell volume than under aerobic conditions, but plasma membrane integrity was maintained. Extended anoxic hypotonic incubation (300 minutes) produced no further change in tissue water, but the inulin-diffusible space was increased and electron micrographs revealed breaks in the plasma membranes primarily in association with large subsarcolemmal blebs. Likewise, myocardial slices incubated in isotonic anoxic media for 240 minutes and hypotonic anoxic media for 60 minutes had an increased inulin-diffusible space and the ultrastructural appearance was similar. This ultrastructural appearance is indistinguishable from that observed in myocytes lethally injured by ischemia. Measurements of tissue osmolarity during total ischemia showed that osmotically induced cell swelling could occur in ischemic myocardium prior to the onset of plasma membrane disruption. Our results indicate that cell swelling per se is incapable of rupturing plasma membranes; however, after prolonged periods of energy deficiency, the plasma membrane or its cytoskeletal scaffold become injured, which allows the membrane to rupture if the cell is swollen, as might occur during ischemia or reperfusion.
在含氧或缺氧的 Krebs-Ringer 磷酸盐培养基中孵育的薄心肌切片中，已对细胞肿胀与质膜破坏之间的关系进行了评估。使用电子显微镜和菊粉可扩散空间的测量来监测质膜完整性。完整细胞的细胞内空间会排除菊粉；因此，组织菊粉含量的增加是质膜完整性丧失的一个极好标志。需氧切片暴露于低渗培养基期间细胞体积增加，但菊粉可扩散空间未增加，电子显微镜照片显示未检测到质膜改变。同样，在长时间缺氧等渗孵育期间，未观察到质膜损伤的证据。在缺氧低渗培养基中孵育 60 分钟导致细胞体积的增加比有氧条件下更大，但质膜完整性得以维持。延长的缺氧低渗孵育（300 分钟）未使组织水分进一步变化，但菊粉可扩散空间增加，电子显微镜照片显示质膜破裂主要与大的肌膜下泡相关。同样，在等渗缺氧培养基中孵育 240 分钟和在低渗缺氧培养基中孵育 60 分钟的心肌切片菊粉可扩散空间增加，超微结构外观相似。这种超微结构外观与缺血致死性损伤的心肌细胞中观察到的无法区分。完全缺血期间组织渗透压的测量表明，在质膜破坏开始之前，缺血心肌中可能发生渗透诱导的细胞肿胀。我们的结果表明，细胞肿胀本身无法使质膜破裂；然而，在长时间能量缺乏后，质膜或其细胞骨架支架会受损，如果细胞肿胀，如在缺血或再灌注期间可能发生的情况，这会使膜破裂。
