基于Notch1信号通路探讨杭白菊总黄酮治疗心肌肥厚小鼠的机制研究

Protective mechanism of total flavonoids from Chrysanthemum morifolium in mice with cardiac hypertrophy based on Notch1 signaling pathway

目的探讨杭白菊总黄酮对异丙肾上腺素(ISO)诱导的心肌肥厚小鼠的保护作用及其机制。方法将40只雄性小鼠分为对照组、总黄酮组、模型组和干预组,每组各10只。总黄酮组和干预组给予总黄酮(100 mg/kg)灌胃处理14 d,对照组和模型组给予相同体积的等渗NaCl溶液灌胃处理。模型组和干预组于第8天皮下多点注射ISO(5 mg/kg,0.5 mL)连续7 d以建立小鼠心肌肥厚模型,对照组和总黄酮组给予皮下相同体积等渗NaCl溶液多点注射。计算所有小鼠的左室射血分数(LVEF)、左室短轴缩短率(LVFS)、左心室质量指数(LVMI)、全心质量指数(HMI)、心脏质量/胫骨长度(HW/TL)比值。检测心肌组织中超氧化物歧化酶(SOD)、丙二醛及活性氧的含量;并且采用实时定量逆转录聚合酶链反应(qRT-PCR)法检测Collagen-1、Notch1、Hes1、心肌肌球蛋白重链β(β-MHC)、心房利钠肽(ANP)、Nox4及Nrf2的mRNA表达水平。结果4组小鼠间LVEF、LVFS、LVMI、HMI、HW/TL、SOD、丙二醛及活性氧含量的比较,差异均有统计学意义(F=62.114、18.814、59.824、66.375、48.362、59.677、46.195、48.257,P均<0.001)。且与对照组相比,模型组小鼠的LVEF、LVFS及SOD水平均明显降低,LVMI、HMI、HW/TL、丙二醛及活性氧含量均显著升高(P均<0.05),而干预组小鼠的LVEF[(56±6)%vs.(38±5)%]、LVFS[(32±5)%vs.(22±4)%]、SOD水平均显著高于模型组,LVMI[(4.1±0.4)mg/g vs.(5.8±0.5)mg/g]、HMI[(5.3±1.1)mg/g vs.(6.5±0.6)mg/g]、HW/TL[(9.8±1.2)mg/mm vs.(12.4±1.3)mg/mm]、丙二醛及活性氧含量较模型组均显著降低(P均<0.05)。4组小鼠间Collagen-1、Notch1、Hes1、β-MHC、ANP、Nox4及Nrf2的mRNA表达水平的比较,差异均有统计学意义(F=85.372、43.865、69.841、36.358、23.964、48.354、57.781,P均<0.001)。且与对照组相比,模型组小鼠Collagen-1、Notch1、Hes1、β-MHC、ANP、Nox4的mRNA表达水平均明显上调,Nrf2的mRNA表达水平明显下调(P均<0.05),而干预组小鼠Collagen-1、Notch1、Hes1、β-MHC、ANP及Nox4的mRNA表达水平较模型组均显著下调,Nrf2的mRNA表达水平较模型组明显上调(P均<0.05)。结论杭白菊总黄酮可以明显减轻ISO诱导产生的心肌肥厚,其作用与阻断Notch1信号通路,从而减轻心肌氧化应激损伤及抑制心肌组织纤维化的进程有关。

Objective To investigate the protective effect of total flavonoids from Chrysanthemum morifolium in mice with isoprenaline(ISO)-induced cardiac hypertrophy and its mechanism.Methods Forty male mice were randomly divided into the control group,total flavonoids group,model group and treatment group,10 mice in each group.Mice in the total flavonoids group and treatment group were given total flavonoids(100 mg/kg)by gavage for 14 days,and those in the control group and model group were given isotonic NaCl solution by gavage.Mice in the model group and treatment group were subcutaneously injected with ISO(5 mg/kg,0.5 mL)for 7 consecutive days to establish a mouse model of cardiac hypertrophy on 8 d,and those in the control group and total flavonoids group received the same volume of isotonic NaCl solution by subcutaneous injection.The levels of left ventricular ejection fraction(LVEF),left ventricular short axis fractional shortening(LVFS),left ventricular mass index(LVMI),heart mass index(HMI),and heart weight/tibia length(HW/TL)were calculated.The contents of superoxide dismutase(SOD),malondialdehyde and reactive oxygen species were compared.The mRNA expressions of Collagen-1,Notch1,Hes1,β-myosin heavy chain(β-MHC),atrial natriuretic peptide(ANP),Nox4 and Nrf2 were detected by quantitative reverse transcription polymerase chain reaction(qRT-PCR).Results The levels of LVEF,LVFS,LVMI,HMI,HW/TL,SOD,malondialdehyde and reactive oxygen species among the four groups were significantly different(F=62.114,18.814,59.824,66.375,48.362,59.677,46.195,48.257;all P<0.001).Compared with the control group,the levels of LVEF,LVFS and SOD decreased,and the levels of LVMI,HMI,HW/TL,malondialdehyde and reactive oxygen species increased remarkably in the model group(all P<0.05).The levels of LVEF[(56±6)%vs.(38±5)%],LVFS[(32±5)%vs.(22±4)%]and SOD were higher,and the levels of LVMI[(4.1±0.4)mg/g vs.(5.8±0.5)mg/g],HMI[(5.3±1.1)mg/g vs.(6.5±0.6)mg/g],HW/TL[(9.8±1.2)mg/mm vs.(12.4±1.3)mg/mm],malondialdehyde and reactive oxygen species were lower in the treatment group than in the model group(all P<0.05).The mRNA expressions of Collagen-1,Notch1,Hes1,β-MHC,ANP,Nox4 and Nrf2 among the four groups were significantly different(F=85.372,43.865,69.841,36.358,23.964,48.354,57.781;all P<0.001).The mRNA expressions of Collagen-1,Notch1,Hes1,β-MHC,ANP and Nox4 obviously up-regulated,and the Nrf2 mRNA expression observably down-regulated in the model group as compared with the control group(all P<0.05).The mRNA expressions of Collagen-1,Notch1,Hes1,β-MHC,ANP and Nox4 were lower,and the Nrf2 mRNA expression was higher in the treatment group than in the model group(all P<0.05).Conclusion Total flavonoids in Chrysanthemum morifolium can significantly alleviate ISO-induced cardiac hypertrophy,which may be related to the blockade of Notch signaling pathway,reduction of myocardial oxidative stress injury and inhibition of myocardial fibrosis.