Nrf2激活剂缓解低氧性肺动脉高压大鼠肺血管重构

Nrf2 activator relieves pulmonary vascular remodeling in rats with hypoxic pulmonary arterial hypertension

目的探讨核因子E2相关因子2(Nrf2)激活对低氧性肺动脉高压(PAH)大鼠血管重构的影响,并初步探讨其机制。方法将大鼠分为:对照组、低氧组(低氧处理大鼠)、Nrf2激活组(低氧处理前1周每天灌胃5 mg/kg Nrf2激动剂莱菔硫烷,连续4周),每组8只。检测心肺血流动力学和右心室肥大指标平均肺动脉压(mPAP),并计算右心室肥厚指数=右心室(RV)/(左心室+室间隔)(LV+S);HE染色测定肺血管重构相关指标并计算肺小动脉血管壁面积(WA)/血管总面积(TA),血管中膜厚度(MT)/血管动脉外径(ED);硫代巴比妥酸法、氮蓝四唑法分别检测氧化应激指标丙二醛(MDA)、超氧化物岐化酶(SOD)活性;qRT-PCR检测肺动脉中基质金属蛋白酶(MMP)-2、MMP-9 mRNA水平;Western blot检测肺动脉组织中Nrf2、抗氧化反应元件(ARE)、磷酸酰胺腺嘌呤二核苷酸醌氧化还原酶-1(NQO-1)、血红素氧合酶1(HO1)蛋白水平。结果与对照组相比,低氧组mPAP、RV/(LV+S),WA/TA、MT/ED水平,肺动脉组织中MDA水平,MMP-2、MMP-9 mRNA水平,胞核Nrf2、ARE、NQO1、HO1蛋白水平升高(P<0.05);肺动脉组织中SOD活性,胞质Nrf2蛋白水平降低(P<0.05)。与低氧组相比,Nrf2激活组mPAP、RV/(LV+S)水平,WA/TA、MT/ED水平,肺动脉组织中MDA水平,MMP-2、MMP-9 mRNA水平,胞质Nrf2蛋白水平降低(P<0.05);肺动脉组织中SOD活性,胞核Nrf2、ARE、NQO1、HO1蛋白水平升高(P<0.05)。结论Nrf2激活可延缓PAH造成的血管重构,该作用可能是通过激活Nrf2/ARE通路实现的。

Objective To investigate the effect of activation of nuclear factor E2-related factor 2(Nrf2)on vascular remodeling in hypoxic-induced pulmonary hypertension(PAH)rats and its mechanism.Methods The rats were divided into four groups with eight in each:control group,hypoxic group(hypoxic treatment of rats),Nrf2 activated group(gavage 5 mg/kg Nrf2 agonist sulforaphane every day for 4 weeks before hypoxic treatment).The cardiopulmonary hemodynamics and right ventricular hypertrophy index mean pulmonary artery pressure(mPAP)were measured,the right ventricular hypertrophy index=right ventricle(RV)/(left ventricle+interventricular septum)(LV+S)were calculated;the related indexes of pulmonary vascular remodeling were measured and the wall area(WA)/total area(TA)of pulmonary arterioles and the thickness of vascular mesothelium(MT)/external diameter(ED)of pulmonary arterioles were calculated;malondialdehyde(MDA)and superoxide dismutase(SOD)were measured by thiobarbituric acid method and nitrogen blue tetrazole method;the mRNA of matrix metalloproteinase(MMP)and MMP-9 in pulmonary artery were detected by qRT-PCR;and the protein level of Nrf2,antioxidant response element(ARE),NADPH quinineoxidoreductase-1(NQO-1)and heme oxygenase1(HO1)were measured by Western blot.Results Compared with the control group,the level of mPAP,RV/(LV+S),WA/TA and MT/ED,MDA and mRNA level of MMP-2 and MMP-9 in pulmonary artery tissue,the level of Nrf2,ARE,NQO1 and HO1 proteins in the nucleus of the hypoxic group were all increased(P<0.05);and SOD activity in pulmonary artery tissue and level of Nrf2 protein in plasma were decreased(P<0.05).Compared with hypoxia group,the levels of mPAP,RV/(LV+S),levels of WA/TA and MT/ED,level of MDA and mRNA levels of MMP-2 and MMP-9 in pulmonary artery tissue,the level of Nrf2 protein in cytoplasm of the Nrf2 activation group were decreased(P<0.05);and SOD activity in pulmonary artery tissue and levels of Nrf2,ARE,NQO1 and HO1 proteins in the nucleus were increased(P<0.05).Conclusions Nrf2 activation may delay the vascular remodeling induced by PAH,and potential mechanism is the pathway of Nrf2/ARE activation.