摘要
目的:探讨血管紧张素Ⅱ(AngⅡ)诱导的高血压大鼠肠系膜动脉中蛋白磷酸酶2A(PP2A)被激活的可能机制。方法:选用雄性Sprague-Dawley(SD)大鼠,采用皮下埋置微量渗透泵持续灌注AngⅡ(500 ng·kg^-1·min^-1,14 d)的方法复制高血压模型。40只大鼠被随机分为4组,即对照(control)组(n=10)、AngⅡ组(n=10)、坎地沙坦(CAN;AngⅡ1型受体阻滞剂)+AngⅡ组(n=10)和CAN组(n=10)。CAN+AngⅡ组和CAN组均于埋置微量渗透泵后第1天开始予以坎地沙坦酯(10 mg·kg^-1·d^-1)灌胃。术后第15天处死大鼠,留取血清和肠系膜动脉。用无创大鼠血压测量仪检测大鼠尾动脉收缩压,采用生物素双抗体夹心酶联免疫吸附(ELISA)法测定血清AngⅡ含量,采用Western blot方法检测肠系膜动脉中内皮型一氧化氮合酶(eNOS)蛋白表达、eNOS Ser1177磷酸化水平、PP2A催化亚基(PP2Ac)蛋白表达、PP2Ac Tyr307磷酸化水平及PP2A内源性抑制蛋白I PP2A 2表达水平,采用PP2A活性检测试剂盒测定肠系膜动脉PP2A活性变化。结果:(1)与control组相比,AngⅡ组大鼠收缩压显著升高(P<0.05);与AngⅡ组相比,CAN+AngⅡ组和CAN组收缩压显著降低(P<0.05)。(2)与control组相比,AngⅡ组和CAN+AngⅡ组大鼠血清AngⅡ含量显著升高(P<0.05)。(3)与control组相比,AngⅡ组肠系膜动脉eNOS Ser1177磷酸化水平显著降低(P<0.05),PP2A活性显著增高(P<0.05),且二者变化呈负相关(r=-0.842,P<0.05);与AngⅡ组相比,CAN+AngⅡ组eNOS Ser1177磷酸化水平显著上调(P<0.05),PP2A活性显著降低(P<0.05)。(4)与control组相比,AngⅡ组PP2Ac Tyr307磷酸化水平和I PP2A 2蛋白表达均显著降低(P<0.05);与AngⅡ组相比,CAN+AngⅡ组PP2Ac Tyr307磷酸化水平和I PP2A 2蛋白表达显著增高(P<0.05)。(5)CAN组各项指标差异无统计学意义,各组间eNOS及PP2Ac蛋白表达差异亦均无统计学意义。结论:在AngⅡ诱导的高血压大鼠肠系膜动脉中,AngⅡ通过其1型受体介导,降低PP2Ac Tyr307磷酸化水平�
AIM:To investigate the mechanism of protein phosphatase 2A(PP2A)activation in mesenteric arteries of angiotensinⅡ(AngⅡ)-induced hypertensive rats.METHODS:Adult male Sprague-Dawley(SD)rats were subjected to AngⅡinfusion(500 ng·kg^-1·min^-1)using osmotic minipump up to 14 d to established the hypertension model.The rats(n=40)were randomly divided into 4 groups:control group(n=10),AngⅡgroup(n=10),candesartan(CAN;AngⅡtype 1 receptor blocker)+AngⅡgroup(n=10)and CAN group(n=10).The rats in CAN+AngⅡgroup and CAN group were administered with candesartan ester at the dose of 10 mg·kg^-1·d^-1 by gavage on the first day after implantation of osmotic minipump.The rats were sacrificed on the 15th day after minipump implantation.Serum and mesenteric arteries were collected.Systolic blood pressure was measured by tail-cuff method.The serum levels of AngⅡwere measured by ELISA.The protein levels of endothelial nitric oxide synthase(eNOS),phosphorylated eNOS(Ser1177),PP2A catalytic subunit(PP2Ac),phosphorylated PP2Ac(Tyr307)and PP2A inhibitor 2(I PP2A 2)in the mesenteric arteries were determined by Western blot.The activity of PP2A in the arteries was detected using PP2A activity assay kit.RESULTS:Compared with control group,the systolic blood pressure in AngⅡgroup was significantly increased(P<0.05),while those in CAN+AngⅡgroup and CAN group were significantly decreased(P<0.05).The serum levels of AngⅡin AngⅡgroup and CAN+AngⅡgroup were significantly higher than that in control group(P<0.05).Compared with control group,the phosphorylation levels of eNOS Ser1177 were decreased in AngⅡgroup(P<0.05),but the activity of PP2A was significantly increased(P<0.05),and Pearson correlation analyses showed a negative correlation between PP2A activity and eNOS S1177 phosphorylation(r=-0.842,P<0.05).Compared with AngⅡgroup,the phosphorylation levels of eNOS Ser1177 in CAN+AngⅡgroup were significantly increased(P<0.05),but the activity of PP2A was reduced(P<0.05).Compared with control group,the protein leve
作者
于敏
姜君财
骆妍蓓
张倩
丁菁
陆德琴
YU Min;JIANG Jun-cai;LUO Yan-bei;ZHANG Qian;DING Jing;LU De-qin(Department of Pathophysiology,Guizhou Provincial Key Laboratory of Pathogenesis & Drug Research on Common Chronic Diseases,Guizhou Medical University,Guiyang 550025,China)
出处
《中国病理生理杂志》
CAS
CSCD
北大核心
2019年第10期1729-1735,共7页
Chinese Journal of Pathophysiology
基金
国家自然科学基金资助项目(No.31460267)
贵州省科学基金资助项目(黔科合LH字[2014]7088)
