藏红花素通过激活Nrf2/HO-1信号减轻压力负荷引起的心肌肥厚

Crocin alleviates pressure overload-induced cardiac hypertrophy by upregulating Nrf2/HO-1 signaling

目的观察藏红花素(crocin,Cro)对压力负荷诱导心肌肥厚的影响并探讨其可能机制。方法将C57BL/6J小鼠随机分为4组:假手术组(sham)、主动脉缩窄(TAC)组、Cro+TAC组和Cro+Nrf2抑制剂ML385+TAC组。采用主动脉缩窄术建立心肌肥厚模型,sham组和TAC组术后用生理盐水灌胃,Cro+TAC组术后用Cro(40 mg/kg)灌胃,Cro+ML385+TAC组术后用Cro(40 mg/kg)灌胃,同时腹腔注射ML385(30 mg/kg),持续4周。检测心脏功能包括左心室射血分数(LVEF),左心室短轴缩短率(LVFS)和心脏舒张末期室间隔厚度(IVST),计算心脏/体质量比值(HW/BW),逆转录聚合酶链式反应(RT-PCR)检测心房钠尿肽(ANP)和脑钠肽(BNP)的mRNA水平,麦胚凝集素(WGA)染色观察心肌横截面积,Masson染色观察心肌纤维化,ELISA检测心肌组织MDA含量和SOD活性,Western blot检测SOD2、gp91^(phox)、Nrf2和HO-1表达。结果与sham组相比,TAC组LVEF和LVFS降低(P<0.05),IVST增加(P<0.05),HW/BW值、ANP和BNP mRNA水平以及心肌细胞横截面积增大(P<0.05),纤维化程度和MDA含量增加(P<0.05),SOD活性降低(P<0.05),SOD2、Nrf2和HO-1表达降低(P<0.01),gp91^(phox)表达增加(P<0.01)。与TAC组相比,Cro+TAC组LVEF和LVFS增加(P<0.05),IVST降低(P<0.05),HW/BW值、ANP和BNP mRNA水平以及心肌细胞横截面积减小(P<0.05),纤维化程度和MDA含量降低(P<0.05),SOD活性增加(P<0.05),SOD2、Nrf2和HO-1表达升高(P<0.01),gp91^(phox)表达降低(P<0.01)。与Cro+TAC组相比,Cro+ML385+TAC组LVEF和LVFS降低(P<0.05),IVST增加(P<0.05),HW/BW值、ANP和BNP mRNA水平以及心肌细胞横截面积增大(P<0.05),纤维化程度和MDA含量增加(P<0.05),SOD活性降低(P<0.05),SOD2、Nrf2和HO-1表达降低(P<0.01),gp91^(phox)表达增加(P<0.01)。结论Cro通过上调Nrf2/HO-1信号抑制心肌纤维化和氧化应激改善压力负荷诱导的心肌肥厚。

Objective To investigate the effect of crocin(Cro)on pressure overload-induced cardiac hypertrophy and explore its underlying mechanism.Methods C57BL/6J mice were randomly divided into four groups:sham group,transverse aortic constriction(TAC)group,Cro+TAC group and Cro+ML385(a Nrf2 inhibitor)+TAC group.Cardiac hypertrophy model was established by transverse aortic constriction.Mice in sham group and TAC group were given saline by gavage,while mice in Cro+TAC group were given Cro(40 mg/kg)by gavage after transverse aortic constriction surgery,and mice in Cro+ML385+TAC group were simultaneously given Cro(40 mg/kg)by gavage and an intraperitoneal injection of ML385(30 mg/kg)for four weeks.Cardiac functions including left ventricular ejection fraction(LVEF),left ventricular fractional shortening(LVFS)and end-diastolic ventricular septal thickness(IVST)were measured.The ratio of heart weight to body weight(HW/BW)was calculated.The mRNA levels of ANP and BNP were detected by reverse transcription polymerase chain reaction(RT-PCR).The myocardial cross-sectional area was observed by wheat germ agglutinin(WGA)staining.Myocardial fibrosis was assessed by Masson staining.MDA content and SOD activity in myocardial tissue were detected by ELISA.The protein levels of SOD2,gp91^(phox),Nrf2 and HO-1 were determined by Western blot.Results Compared with sham group,LVEF and LVFS were decreased significantly in TAC group,and IVST,HW/BW ratio,the mRNA levels of ANP and BNP,the cell cross-sectional area,the fibrosis and MDA content were increased(P<0.05).Compared with sham group,SOD activity and the protein levels of SOD2,Nrf2 and HO-1 were decreased in TAC group(P<0.05),while gp91^(phox) protein level was elevated(P<0.01).Compared with TAC group,LVEF and LVFS were increased significantly in Cro+TAC group,meanwhile,IVST,HW/BW ratio,the mRNA levels of ANP and BNP,the cell cross-sectional area,the fibrosis and MDA content were decreased in Cro+TAC group(P<0.05).Compared with TAC group,SOD activity was increased in Cro+TAC group(P<0.05)and the protein levels of SOD2,Nrf2 and HO-1 were increased(P<0.01),while gp91^(phox) protein level was inhibited(P<0.01).Compared with Cro+TAC group,LVEF and LVFS were decreased significantly in Cro+ML385+TAC group(P<0.05),meanwhile,IVST,HW/BW ratio,the mRNA levels of ANP and BNP,the cell cross-sectional area,the fibrosis and MDA content were increased in Cro+ML385+TAC group(P<0.05).In addition,compared with Cro+TAC group,SOD activity was decreased in Cro+ML385+TAC group(P<0.05),the protein levels of SOD2,Nrf2 and HO-1 were decreased(P<0.01),while gp91^(phox) protein level was elevated(P<0.01).Conclusion Crocin can inhibit the fibrosis and improve the pressure overload-induced cardiac hypertrophy by upregulating Nrf2/HO-1 signaling.