Ivanova S, Botchkina G I, Al-Abed Y, Meistrell M, Batliwalla F, Dubinsky J M, Iadecola C, Wang H, Gregersen P K, Eaton J W, Tracey K J
Laboratory of Biomedical Science, The Picower Institute for Medical Research, Manhasset, New York 11030, USA.
J Exp Med. 1998 Jul 20;188(2):327-40. doi: 10.1084/jem.188.2.327.
To elucidate endogenous mechanisms underlying cerebral damage during ischemia, brain polyamine oxidase activity was measured in rats subjected to permanent occlusion of the middle cerebral artery. Brain polyamine oxidase activity was increased significantly within 2 h after the onset of ischemia in brain homogenates (15.8 +/- 0.9 nmol/h/mg protein) as compared with homogenates prepared from the normally perfused contralateral side (7.4 +/- 0.5 nmol/h/mg protein) (P <0.05). The major catabolic products of polyamine oxidase are putrescine and 3-aminopropanal. Although 3-aminopropanal is a potent cytotoxin, essential information was previously lacking on whether 3-aminopropanal is produced during cerebral ischemia. We now report that 3-aminopropanal accumulates in the ischemic brain within 2 h after permanent forebrain ischemia in rats. Cytotoxic levels of 3-aminopropanal are achieved before the onset of significant cerebral cell damage, and increase in a time-dependent manner with spreading neuronal and glial cell death. Glial cell cultures exposed to 3-aminopropanal undergo apoptosis (LD50 = 160 microM), whereas neurons are killed by necrotic mechanisms (LD50 = 90 microM). The tetrapeptide caspase 1 inhibitor (Ac-YVAD-CMK) prevents 3-aminopropanal-mediated apoptosis in glial cells. Finally, treatment of rats with two structurally distinct inhibitors of polyamine oxidase (aminoguanidine and chloroquine) attenuates brain polyamine oxidase activity, prevents the production of 3-aminopropanal, and significantly protects against the development of ischemic brain damage in vivo. Considered together, these results indicate that polyamine oxidase-derived 3-aminopropanal is a mediator of the brain damaging sequelae of cerebral ischemia, which can be therapeutically modulated.
为阐明缺血期间脑损伤的内源性机制，我们检测了大脑中动脉永久性闭塞大鼠的脑多胺氧化酶活性。与正常灌注的对侧脑匀浆（7.4±0.5 nmol/h/mg蛋白）相比，脑缺血开始后2小时内，脑匀浆中的脑多胺氧化酶活性显著增加（15.8±0.9 nmol/h/mg蛋白）（P<0.05）。多胺氧化酶的主要分解产物是腐胺和3-氨基丙醛。尽管3-氨基丙醛是一种强效细胞毒素，但此前缺乏关于脑缺血期间是否产生3-氨基丙醛的重要信息。我们现在报告，大鼠永久性前脑缺血后2小时内，3-氨基丙醛在缺血脑中蓄积。在显著的脑细胞损伤开始之前，3-氨基丙醛就达到了细胞毒性水平，并随着神经元和胶质细胞的广泛死亡而呈时间依赖性增加。暴露于3-氨基丙醛的胶质细胞培养物会发生凋亡（半数致死剂量=160μM），而神经元则通过坏死机制死亡（半数致死剂量=90μM）。四肽半胱天冬酶1抑制剂（Ac-YVAD-CMK）可防止3-氨基丙醛介导的胶质细胞凋亡。最后，用两种结构不同的多胺氧化酶抑制剂（氨基胍和氯喹）治疗大鼠，可减弱脑多胺氧化酶活性，防止3-氨基丙醛的产生，并显著保护大鼠免受体内缺血性脑损伤的发展。综合考虑，这些结果表明，多胺氧化酶衍生的3-氨基丙醛是脑缺血脑损伤后遗症的介质，可通过治疗进行调节。
