Takuma Kazuhiro, Phuagphong Patamawan, Lee Eibai, Enomoto Riyo, Mori Koichi, Baba Akemichi, Matsuda Toshio
Department of Analytical Chemistry, Faculty of Pharmaceutical Sciences and High Technology Research Center, Kobe Gakuin University, Kobe, Japan.
Jpn J Pharmacol. 2002 May;89(1):64-71. doi: 10.1254/jjp.89.64.
We examined the effect of 3-ethyl-3-(ethylaminoethyl)-1-hydroxy-2-oxo-1-triazene (NOC12), a nitric oxide (NO) donor, on apoptosis in cultured astrocytes. Reperfusion after hydrogen peroxide (H2O2) exposure caused a decrease in cell viability, loss of mitochondrial membrane potential, caspase-3 activation, DNA ladder formation, and nuclear condensation. NOC12 at 10-100 microM significantly attenuated these apoptotic changes, while the NO donor at 1 mM caused cell injury and exacerbated the H202-induced cell injury. NOC12 increased intracellular cGMP levels in a dose dependent manner with the maximal effect at 100 microM. The protective effect of NOC12 was mimicked by the NO-independent guanylate cyclase activator 3-(5'-hydroxymethyl-2'-furyl)-1-benzyl indazole, and was attenuated by the guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) and the cGMP-dependent protein kinase inhibitor KT5823. ODQ and KT5823 did not block but rather exacerbated the cytotoxic effect of NOC12 at 1 mM. These findings demonstrate that lower concentrations of NOC12 inhibit the H2O2-induced apoptosis of astrocytes in a cGMP-dependent way, but higher concentrations of NOC12 show a toxic effect on astrocytes in a cGMP-independent way.
我们研究了一氧化氮（NO）供体3-乙基-3-（乙氨基乙基）-1-羟基-2-氧代-1-三氮烯（NOC12）对培养星形胶质细胞凋亡的影响。过氧化氢（H2O2）暴露后的再灌注导致细胞活力下降、线粒体膜电位丧失、半胱天冬酶-3激活、DNA梯形条带形成和核浓缩。10-100微摩尔的NOC12显著减轻了这些凋亡变化，而1毫摩尔的该NO供体则导致细胞损伤并加剧了H2O2诱导的细胞损伤。NOC12以剂量依赖方式增加细胞内cGMP水平，在100微摩尔时达到最大效应。NO非依赖性鸟苷酸环化酶激活剂3-（5'-羟甲基-2'-呋喃基）-1-苄基吲唑模拟了NOC12的保护作用，而鸟苷酸环化酶抑制剂1H-[1,2,4]恶二唑并[4,3-a]喹喔啉-1-酮（ODQ）和cGMP依赖性蛋白激酶抑制剂KT5823则减弱了该保护作用。ODQ和KT5823并未阻断而是加剧了1毫摩尔NOC12的细胞毒性作用。这些发现表明，较低浓度的NOC12以cGMP依赖方式抑制H2O2诱导的星形胶质细胞凋亡，但较高浓度的NOC12以cGMP非依赖方式对星形胶质细胞显示出毒性作用。
