紫檀芪激活血红素加氧酶-1减轻小鼠脑缺血再灌注后线粒体氧化损伤

Pterostilbene relieves mitochondrial oxidative damage in mice cerebral ischemia reperfusion model by activing heme oxygenase-1

目的:探索紫檀芪(pterostilbene,PTE)对小鼠脑缺血再灌注(IR)后线粒体氧化损伤的作用及可能机制。方法:通过双侧颈总动脉阻断法建立小鼠脑IR模型,腹腔注射PTE或Zn PP(血红素加氧酶-1抑制剂),动物随机均分为IR组、PTE+IR组、PTE+Zn PP+IR组、Zn PP+IR组,并且PTE有2.5 mg/kg、5 mg/kg、10 mg/kg三个剂量组。然后,进行神经功能评分;通过干湿比重法测定脑水肿;火焰光度法测定Na^+含量;Neu N和TUNEL法测定细胞存活和凋亡;通过线粒体膜电位(MMP)、线粒体活性氧(ROS)产物和线粒体复合物I和IV活性测定来检测线粒体的氧化应激损伤;通过Western Blot检测血红素加氧酶-1(HO-1)、NADPH醌氧化还原酶-1(NQO1)、谷胱甘肽S-转移酶(GST)、线粒体和胞浆细胞色素c蛋白的表达。结果:PTE可以提高小鼠的神经功能评分、减轻脑水肿和降低脑Na^+含量。PTE上调HO-1、NQO1和GST的表达,提高MMP、线粒体复合体I/IV活性和线粒体细胞色素c水平,减少线粒体ROS产物和降低胞浆细胞色素c水平,并且有一定的剂量依赖性。但是,PTE的这些作用可以被HO-1的抑制剂Zn PP逆转。结论:在脑IR模型小鼠,PTE通过激活HO-1信号减轻线粒体氧化应激损伤和细胞死亡,从而发挥脑保护作用。

Objective： To explore the effects of pterostilbene （PTE） on mitochondrial oxidative damage in mice cerebral ischemia reperfusion （IR） model and the possible mechanisms. Methods： IR injury was induced by bilateral common carotid arteries occlusion in mice using non-traumatic aneurysm clips. The mice received PTE or ZnPP, the inhibitor of heme oxygenase-1 （HO-1） by intraperitoneal injection. The mice were randomly divided into four groups： IR; PTE ＋ IR; PTE ＋ZnPP ＋ IR; ZnPP ＋ IR. The dose of PTE used was 2.5 mg/kg, 5 mg/kg and 10 mg/kg. The neurological scores were assessed and the brain edema was detected by wet-dried weight method. The sodium ion level in the brain was measured by flame photometry. The neuronal survival and the apoptotic ratio in IR-injured brains were detected by NeuN and TUNEL assay. The mitochondrial oxidative stress injury was evaluated through the measurements of mitochondrial membrane potential （MMP）, reactive oxygen species （ROS） production, mitochondrial complex I and IV activity. The protein expressions of HO-1, NADPH quinone oxidoreductase 1 （ NQO1 ）, glutathione s-transferases （ GST）, mitochon- drial and cytosolic cytochrome c was detected by Western Blot. Results ： PTE improved neurological scores of mice, lowered brain edema and decreased the sodium ion content of brain. It up-regulated HO-1, NQO1 and GST expression. Moreover, PTE resulted in a well-preserved mitochondrial MMP, mitochondria complex I/IV activity, mitochondrial cyto- chrome c level while it reduced mitocbondrial ROS production and cytosolic cytochrome c level. However, the dose- dependent PTE-elevated mitochondrial function was reversed by ZnPP. Conclusion： In mice cerebral IR model, PTE plays a role in the brain protection by reducing mitochondrial oxidative damage and cell death through the activation of HO-1 signal.