Sakaida I, Thomas A P, Farber J L
Department of Pathology and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107.
Am J Physiol. 1992 Sep;263(3 Pt 1):C684-90. doi: 10.1152/ajpcell.1992.263.3.C684.
The killing of cultured hepatocytes by 1 mM sodium cyanide was reduced by 100 microM chlorpromazine or cytochalasin B (25 micrograms/ml) or by lowering the pH of the culture medium to 6.0. In each case, ATP was depleted despite the decreased number of dead cells. The cell killing by cyanide was accompanied by an accelerated release of 3H-labeled arachidonate from phospholipids. Depletion of ATP by oligomycin did not accelerate phospholipid degradation or kill the hepatocytes. Chlorpromazine, cytochalasin B, and extracellular acidosis reduced the rate of phospholipid degradation in control cells as well as the increase that occurred with cyanide. The calcium ionophore A23187 increased phospholipid degradation and killed the hepatocytes. Chlorpromazine and extracellular acidosis, but not cytochalasin B, protected the cells and prevented the increased lipid degradation in response to A23187. After addition of cyanide, cytosolic free calcium ([Ca2+]i) did not change for 71 +/- 8 min, at which time it rose to a plateau of 683 +/- 210 nM within 10 min. A second and larger rise occurred after 84 +/- 8 min and before the death of the cells at 89 +/- 8 min. Treatment with 3.5 mM ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid, as well as removal of extracellular calcium, prevented these late increases in [Ca2+]i without affecting the loss of viability. It is concluded that cyanide kills cultured hepatocytes by a mechanisms that is likely related to an accelerated degradation of phospholipids. This change in lipid metabolism is not mediated by a rise in [Ca2+]i but rather may relate to an alteration in the interaction between the cytoskeleton and the plasma membrane.
1 mM 氰化钠对培养的肝细胞的杀伤作用，可被 100 μM 氯丙嗪或细胞松弛素 B（25 μg/ml）减弱，或者通过将培养基的 pH 降至 6.0 来减弱。在每种情况下，尽管死亡细胞数量减少，但 ATP 仍被耗尽。氰化物对细胞的杀伤伴随着磷脂中 3H 标记的花生四烯酸的加速释放。寡霉素使 ATP 耗尽并不会加速磷脂降解或杀死肝细胞。氯丙嗪、细胞松弛素 B 和细胞外酸中毒降低了对照细胞中磷脂降解的速率以及氰化物作用时发生的磷脂降解增加。钙离子载体 A23187 增加了磷脂降解并杀死了肝细胞。氯丙嗪和细胞外酸中毒，但不是细胞松弛素 B，保护了细胞并阻止了因 A23187 引起的脂质降解增加。加入氰化物后，胞质游离钙（[Ca2+]i）在 71±8 分钟内没有变化，此时它在 10 分钟内升至 683±210 nM 的平台期。在 84±8 分钟后且在细胞在 89±8 分钟死亡之前发生了第二次且更大的升高。用 3.5 mM 乙二醇双（β-氨基乙基醚）-N,N,N',N'-四乙酸处理以及去除细胞外钙，可防止这些 [Ca2+]i 的后期升高，而不影响活力丧失。结论是，氰化物通过一种可能与磷脂加速降解相关的机制杀死培养的肝细胞。脂质代谢的这种变化不是由 [Ca2+]i 的升高介导的，而是可能与细胞骨架和质膜之间相互作用的改变有关。
