Goldberg M P, Choi D W
Department of Neurology, Washington University School of Medicine, St. Louis, Missouri 63110.
J Neurosci. 1993 Aug;13(8):3510-24. doi: 10.1523/JNEUROSCI.13-08-03510.1993.
Murine neocortical cell cultures were transiently deprived of both oxygen and glucose, producing widespread neuronal swelling in less than 60 min, followed by neuronal degeneration over the ensuing several hours, despite return to normal medium. Cultured glia (> 95% astrocytes) were irreversibly injured only by oxygen-glucose deprivation exposures exceeding 4-6 hr. Replacing either Na+ or Cl- with impermeant ions blocked acute neuronal swelling but did not prevent delayed neuronal degeneration. While neuronal swelling and death were increased by removing Ca2+ from the exposure medium, combined removal of extracellular Ca2+ together with Na+ or Cl- substitution blocked both acute and delayed injury. If acute swelling was limited by a hyperosmolar medium, then neuronal loss depended on extracellular [Ca2+]. Oxygen-glucose deprivation was associated with a large increase in extracellular glutamate concentration. Both early swelling and later neuronal degeneration were blocked by addition of NMDA receptor antagonists to the exposure medium but not by the AMPA/kainate receptor antagonist 6-cyano-7-dinitroquinoxaline-2,3-dione (CNQX), dihydropyridines nifedipine or nimodipine, or TTX. Oxygen-glucose deprivation induced substantial neuronal uptake of tracer 45Ca2+ from the exposure medium that was reduced by NMDA receptor antagonists and closely paralleled the degree of subsequent neuronal loss. These observations suggest the presence of two distinct components of hypoxic injury, each involving NMDA receptor activation and each capable of leading to neuronal death. Acute swelling is mediated by influx of Na+, Cl-, and water, and is enhanced by removal of extracellular Ca2+. Delayed neuronal degeneration depends on the presence of extracellular Ca2+ and correlates closely with cellular uptake of 45Ca2+.
将小鼠新皮质细胞培养物短暂地剥夺氧气和葡萄糖，在不到60分钟内就会导致广泛的神经元肿胀，随后在接下来的几个小时内神经元发生变性，尽管已恢复到正常培养基中。培养的神经胶质细胞（>95%为星形胶质细胞）只有在氧气-葡萄糖剥夺暴露超过4 - 6小时时才会受到不可逆损伤。用不可渗透离子替代Na⁺或Cl⁻可阻断急性神经元肿胀，但不能防止延迟性神经元变性。虽然从暴露培养基中去除Ca²⁺会增加神经元肿胀和死亡，但同时去除细胞外Ca²⁺以及用Na⁺或Cl⁻替代可阻断急性和延迟性损伤。如果急性肿胀受到高渗培养基的限制，那么神经元损失取决于细胞外[Ca²⁺]。氧气-葡萄糖剥夺与细胞外谷氨酸浓度大幅增加有关。在暴露培养基中添加NMDA受体拮抗剂可阻断早期肿胀和后期神经元变性，但AMPA/海人藻酸受体拮抗剂6-氰基-7-二硝基喹喔啉-2,3-二酮（CNQX）、二氢吡啶类硝苯地平或尼莫地平或TTX则不能。氧气-葡萄糖剥夺诱导神经元从暴露培养基中大量摄取示踪剂⁴⁵Ca²⁺，这被NMDA受体拮抗剂减少，并且与随后神经元损失的程度密切平行。这些观察结果表明存在缺氧损伤的两个不同成分，每个成分都涉及NMDA受体激活，并且每个成分都能够导致神经元死亡。急性肿胀由Na⁺、Cl⁻和水的流入介导，并通过去除细胞外Ca²⁺而增强。延迟性神经元变性取决于细胞外Ca²⁺的存在，并且与⁴⁵Ca²⁺的细胞摄取密切相关。
