罗布麻叶提取物的抗高血压作用及其机制研究

Anti-hypertensive Effects of Extracts from Leaves of Apocynum venetum through Activating PI3K/Akt Pathway on Human Endothelial Cells

目的:研究罗布麻叶提取物(extracts from leaves of Apocynum venetum,ELA)的抗高血压作用及其激活磷脂酰肌醇3激酶(PI3K)和(或)蛋白激酶B(Akt)信号转导通路促进一氧化氮释放的作用。方法:采用双肾双夹法建立Beagle犬高血压模型,随后按血压值将Beagle犬随机分为模型组(ig,生理盐水)、马来酸依那普利组(ig,1.66 mg.kg-1)、ELA低剂量组(ig 23mg.kg-1)、高剂量组(ig ELA 46 mg.kg-1)。受试动物在单次给予上述药物后,每隔1 h记录1次动物血压,连续8 h,观察ELA的降压作用;采用细胞培养法,观察ELA对内皮细胞(EAhy 926)一氧化氮(NO)产量和内皮型一氧化氮合酶(eNOS)活性的影响;采用Western blot法,观察ELA对eNOS,磷酸化内皮型一氧化氮合酶(p-eNOS)、磷酸化磷脂酰肌醇3激酶(p-PI3K)以及磷酸化蛋白激酶B(p-Akt)表达量的影响。结果:给药后,ELA高、低剂量组Beagle犬收缩压分别为(140.4±7.5),(136.2±6.8)mmHg;舒张压分别为(63.5±3.3),(72.2±4.4)mmHg;平均血压分别为(88.9±4.7),(93.3±5.2)mmHg,与给药前相比均显著降低(P<0.01);ELA可显著增加EA Hy926细胞NO的释放量(P<0.01),提高eNOS活性(P<0.01);Western blot结果表明,ELA可显著增加p-eNOS,p-PI3K以及p-Akt的表达量,与对照组相比,具有显著差异(P<0.01)。结论:ELA具有明显的降压作用。激活血管内皮细胞内PI3K/Akt信号转导途径,从而促进eNOS磷酸化,提高eNOS活性、增加NO可能是ELA降压作用的机制之一。

Objective： To investigate the anti-hypertensive effects of extracts from leaves of Apocynum venetum L. （ELA） and its mechanisms. Method： Twelve Beagle dogs were used to establish hypertensive mode by two-kidney two-clip method; endothelial cells were cultured to determine effects of ELA on nitric oxide （NO） output and endothelial nitric oxide synthase （eNOS） activities; then Western blot method was involved in current study to detect effects of ELA on eNOS, phospho-endothelial NOS （p-eNOS）, phosph-phosphponositide-3 kinase （p-PI3K） and phosph-protein kinase B （p-Akt） expression. Result： Contractive and diastolic pressure of Beagle dogs showed degression in dose-dependent manner after ELA was administrated （P 〈 0.01 ）. Moreover, NO yield and eNOS activities of EA hy 926 ceils were increased significantly when these ceils incubated with ELA （P 〈 0.01）. It was also showed that ELA enhanced expression of eNOS, p-eNOS, p-PI3K and p-Akt in endothelial cells. Conclusion： ELA shows significant anti-hypertensive properties. The mechanisms may be associated with activation of PI3K/Akt pathway in endothelium.