In this study, we treated PC12 cells with 0-20 μM amyloid-β peptide （25-35） for 24 hours to induce cytotoxicity, and found that 5-20 μM amyloid-β peptide （25-35） decreased PC12 cell viability, but adenosine tr...In this study, we treated PC12 cells with 0-20 μM amyloid-β peptide （25-35） for 24 hours to induce cytotoxicity, and found that 5-20 μM amyloid-β peptide （25-35） decreased PC12 cell viability, but adenosine triphosphate-sensitive potassium channel activator diazoxide suppressed the decrease in PC12 cell viability induced by amyloid-β peptide （25-35）. Diazoxide protected PC12 cells against amyloid-β peptide （25-35）-induced increases in mitochondrial membrane potential and intracellular reactive oxygen species levels. These protective effects were reversed by the selective mitochondrial adenosine triphosphate-sensitive potassium channel blocker 5-hydroxydecanoate. An inducible nitric oxide synthase inhibitor, Nw-nitro-L-arginine, also protected PC12 cells from amyloid-β peptide （25-35）-induced increases in both mitochondrial membrane potential and intracellular reactive oxygen species levels. However, the H202-degrading enzyme catalase could not reverse the amyloid-β peptide （25-35）-induced increase in intracellular reactive oxygen species. A 24-hour exposure to amyloid-13 peptide （25-35） did not result in apoptosis or necrosis, suggesting that the increases in both mitochondrial membrane potential and reactive oxygen species levels preceded cell death. The data suggest that amyloid-β peptide （25-35） cytotoxicity is associated with adenosine triphosphate-sensitive potassium channels and nitric oxide. Regulation of adenosine triphosphate-sensitive potassium channels suppresses PC12 cell cytotoxicity induced by amyloid-β peptide （25-35）.展开更多
基金supported by the Project Sponsored by Yantai Science and Technology Bureau,China,No.2010232
文摘In this study, we treated PC12 cells with 0-20 μM amyloid-β peptide （25-35） for 24 hours to induce cytotoxicity, and found that 5-20 μM amyloid-β peptide （25-35） decreased PC12 cell viability, but adenosine triphosphate-sensitive potassium channel activator diazoxide suppressed the decrease in PC12 cell viability induced by amyloid-β peptide （25-35）. Diazoxide protected PC12 cells against amyloid-β peptide （25-35）-induced increases in mitochondrial membrane potential and intracellular reactive oxygen species levels. These protective effects were reversed by the selective mitochondrial adenosine triphosphate-sensitive potassium channel blocker 5-hydroxydecanoate. An inducible nitric oxide synthase inhibitor, Nw-nitro-L-arginine, also protected PC12 cells from amyloid-β peptide （25-35）-induced increases in both mitochondrial membrane potential and intracellular reactive oxygen species levels. However, the H202-degrading enzyme catalase could not reverse the amyloid-β peptide （25-35）-induced increase in intracellular reactive oxygen species. A 24-hour exposure to amyloid-13 peptide （25-35） did not result in apoptosis or necrosis, suggesting that the increases in both mitochondrial membrane potential and reactive oxygen species levels preceded cell death. The data suggest that amyloid-β peptide （25-35） cytotoxicity is associated with adenosine triphosphate-sensitive potassium channels and nitric oxide. Regulation of adenosine triphosphate-sensitive potassium channels suppresses PC12 cell cytotoxicity induced by amyloid-β peptide （25-35）.
基金This work was supported by the Natural Science Foundation of Jiangsu Province(No.BK2002138).
文摘利用离体海马脑片缺氧无糖(oxygen-glucose deprivation,OGD)损伤模型,探讨七氟醚预处理对神经细胞的保护作用及陔作用与线粒体内膜ATP敏感钾通道(mitochondrial ATP-sensitive potassium channels,mitoK_(ATP)channels)的关系,随机将脑片用2%、4%、6%七氟醚,以及6%七氟醚复合mitoK_(ATP)通道阻滞剂5-羟基奎酸盐(5-hydroxydecanoic acid,5-HD)预处理30min,观察OGD损伤14min复氧1h期间顺向群峰电位(orthodromic population spike,OPS)的变化,并应用透射电镜观察细胞超微结构的改变。结果表明,与单纯OGD组相比,七氟醚预处理可使海马脑片OPS消失时间明显延长(P＜0．01),使OPS明显恢复,其中4%、6%七氟醚组的恢复率均为71．4%(P＜0．05 vs OGD),相应恢复程度为(61．0±42．3)%和(78．7±21．1)%(P＜0．01),而且6%七氟醚的保护作用可被5-HD取消。OGD组的海马CA1区锥体细胞明显水肿,核膜皱缩、破裂,染色质聚集,线粒体肿胀畸形,嵴断裂或消失,而4%和6%七氟醚组仅见海马CA1区锥体细胞轻度水肿,核膜皱缩不明显,染色质均匀,线粒体轻度肿胀。结果提示,七氟醚预处理对大鼠海马脑片OGD损伤有一定的保护作用,且七氟醚对神经细胞的保护作用与激活mitoK_(ATP)通道有关。
