匹诺塞林通过可溶性环氧化物水解酶和环氧二十碳三烯酸对脑缺血大鼠发挥保护作用(英文)

Pinocembrin protects rats against cerebral ischemic damage through soluble epoxide hydrolase and epoxyeicosatrienoic acids

目的:探讨匹诺塞林的脑保护作用与环氧二十碳三烯酸(EETs)及其代谢关键酶可溶性环氧化物水解酶(sEH)之间的关系。方法:大鼠进行大脑中动脉闭塞(MCAO)制备永久性局灶性脑缺血,术后10min,4h,8h和23h经尾静脉注射给予匹诺塞林。手术24h后,大鼠重新麻醉,收集血液和脑等样本进行检测。结果:研究表明匹诺塞林对脑缺血大鼠具有明显的保护作用,可以减轻神经功能障碍及降低梗死面积。重要的是,给予EETs的选择性拮抗剂14,15-EEZE(0.2mg·kg–1)可以减弱匹诺塞林的保护作用。手术24h后,匹诺塞林能明显升高脑缺血大鼠血液和脑组织中14,15-EET水平。匹诺塞林能显著降低缺血大鼠脑中sEH活性并能浓度依赖地抑制重组人sEH活性(IC50,2.58μmol·L–1)。此外,免疫印迹和免疫组化结果表明,10和30mg·kg–1匹诺塞林显著下调sEH蛋白在缺血大鼠大脑,尤其是在海马CA1区的表达。结论:抑制sEH而提高EETs水平可能是匹诺塞林发挥脑保护作用的机制之一。

AIM： To investigate the relationship between cerebroprotection of pinocembrin and epoxyeicosatrienoic acids （EETs） and their regulating enzyme soluble epoxide hydrolase （sEH）. METHODS： Rats underwent middle cerebral artery occlusion （MCAO） to mimic permanent focal ischemia, and pinocembrin was administrated via tail vein injection at 10 min, 4 h, 8 h and 23 h after MCAO. After 24 MCAO, rats were re-anesthetized, and the blood and brain were harvested and analyzed. RESULTS： Pinocembrin displayed significant protective effects on MCAO rats indicated by reduced neurological deficits and infarct volume. Importantly, co-administration of 0.2 mg.kg-I 14, 15-EEZE, a putative selective EET antagonist, weakened the beneficial effects of pinocembrin. 14, 15-EET levels in the blood and brain of rats after 24 h MCAO were elevated in the presence of pinocembrin. In an assay for hy- drolase activity, pinocembrin significantly lowered brain sEH activity of MCAO rats and inhibited recombinant human sEH activity in a concentration-dependent manner （ICs0, 2.58 gmol.L-1）. In addition, Western blot and immunohistochemistry analysis showed that pinocembrin at doses of 10 mg.kg-I and 30 mg-kg-1 significantly down-regulated sEH protein in rat brain, especially the hippocampus CA1 region of MCAO rats. CONCLUSION： Inhibiting sEH and then increasing the potency of EETs may be one of the mechanisms through which pinocembrin provides cerebral protection.