Renolleau Sylvain, Fau Sébastien, Goyenvalle Catherine, Joly Luc-Marie, Chauvier David, Jacotot Etienne, Mariani Jean, Charriaut-Marlangue Christiane
UMR-CNRS, Paris, France.
J Neurochem. 2007 Feb;100(4):1062-71. doi: 10.1111/j.1471-4159.2006.04269.x. Epub 2006 Dec 12.
Hypoxia-ischaemia in the developing brain results in brain injury with prominent features of apoptosis. In the present study, a third generation dipeptidyl broad-spectrum caspase inhibitor, quinoline-Val-Asp(Ome)-CH2-O-phenoxy (Q-VD-OPh), was tested in a model of unilateral focal ischaemia with reperfusion in 7-day-old rats. Q-VD-OPh (1 mg/kg, i.p.) reduced cell death, resulting in significant neuroprotection at 48 h of recovery (infarct volume of 12.6 +/- 2.8 vs. 24.3 +/- 2.2%, p = 0.006). The neuroprotective effects observed at 48 h post-ischaemia hold up at 21 days of survival time and attenuate neurological dysfunction. Analysis by gender revealed that females were strongly protected (6.7 +/- 3.3%, p = 0.006), in contrast to males in which there was no significant effect, when Q-VD-OPh was given after clip removal on the left common carotid artery. Immunoblot analysis demonstrated that Q-VD-OPh inhibits caspase 3 cleavage into its p17 active form and caspase 1 up-regulation and cleavage in vivo. Following ischaemia in P7 rats, males and females displayed different time course and pattern of cytochrome c release and active p17 caspase 3 during the first 24 h of recovery. In contrast, no significant difference was observed for caspase 1 expression between genders. These results indicate that ischaemia activates caspases shortly after reperfusion and that the sex of the animal may strongly influences apoptotic pathways in the pathogenesis of neonatal brain injury. The specificity, effectiveness, and reduced toxicity of Q-VD-OPh may determine the potential use of peptide-derived irreversible caspase inhibitors as promising therapeutics.
发育中的大脑发生缺氧缺血会导致脑损伤，并具有明显的凋亡特征。在本研究中，一种第三代二肽基广谱半胱天冬酶抑制剂喹啉-缬氨酸-天冬氨酸(甲酯)-CH2-O-苯氧基(Q-VD-OPh)在7日龄大鼠单侧局灶性缺血再灌注模型中进行了测试。Q-VD-OPh(1mg/kg，腹腔注射)减少了细胞死亡，在恢复48小时时产生了显著的神经保护作用(梗死体积为12.6±2.8%，而对照组为24.3±2.2%，p=0.006)。缺血后48小时观察到的神经保护作用在存活21天时依然存在，并减轻了神经功能障碍。按性别分析发现，在左侧颈总动脉夹闭去除后给予Q-VD-OPh时，雌性受到强烈保护(6.7±3.3%，p=0.006)，而雄性则无显著效果。免疫印迹分析表明，Q-VD-OPh在体内可抑制半胱天冬酶3切割成其p17活性形式以及半胱天冬酶1的上调和切割。P7大鼠缺血后，雄性和雌性在恢复的前24小时内细胞色素c释放和活性p17半胱天冬酶3的时间进程和模式不同。相比之下，两性之间半胱天冬酶1的表达没有显著差异。这些结果表明，缺血在再灌注后不久就激活了半胱天冬酶，并且动物的性别可能在新生儿脑损伤发病机制中强烈影响凋亡途径。Q-VD-OPh的特异性、有效性和较低的毒性可能决定了肽衍生的不可逆半胱天冬酶抑制剂作为有前景的治疗药物的潜在用途。
