香叶木苷对异丙肾上腺素诱导的大鼠心脏功能紊乱和氧化应激的影响及其分子机制

Effects of geranioside on cardiac dysfunction and oxidative stress induced by isoproterenol in rats and its molecular mechanism

目的:探讨香叶木苷对异丙肾上腺素诱导的大鼠心脏功能紊乱和氧化应激的作用。方法:采用皮下注射异丙肾上腺素的方法建立异丙肾上腺素诱导心肌损伤模型,造模成功后,分为香叶木苷低剂量组、香叶木苷中剂量组和香叶木苷高剂量组,分别灌胃香叶木苷5、10、20 mg/kg。每天给药1次,连续给药10周。检测心率(HR)并通过BL-420F生物机能实验系统记录左心室收缩压(LVSP)和左室射血分数(LVEF);酶联免疫吸附试验(ELISA)检测肌酸激酶同工酶(CK-Mb)、CK、肌钙蛋白I(cTnI)含量的变化;苏木精-伊红染色法(HE)染色观察心肌组织结构的排列情况;免疫组织化学法检测各组心肌组织中Ki67的表达;试剂盒检测丙二醛(MDA)、超氧化物歧化酶(SOD)、乳酸脱氢酶(LDH)的含量变化;免疫印迹法检测B细胞淋巴瘤/白血病-2(Bcl-2)、Bcl-2相关X蛋白(Bax)、半胱氨酸天冬氨酸蛋白酶-3 (Caspase-3)、存活素(Survivin)、Nrf2、过氧化物酶体增殖物激活受体γ共激活因子1α(PGC-1α)、线粒体转录因子A(TFAM)的蛋白表达。结果:香叶木苷中剂量和香叶木苷高剂量显著提高HR,增加LVSP和LVEF水平(P<0.05)。香叶木苷中剂量和香叶木苷高剂量处理后,大鼠血清中CK、CKMB、cTnI的含量均降低(P<0.05)。香叶木苷中剂量和香叶木苷高剂量缓解异丙肾上腺素诱导的心肌损伤。香叶木苷中剂量和香叶木苷高剂量处理后,心肌细胞中Ki67阳性细胞数升高(P<0.05)。香叶木苷中剂量和香叶木苷高剂量促进Survivin的蛋白表达,抑制Bax/Bcl和Caspase-3的蛋白表达(P<0.05)。香叶木苷中剂量和香叶木苷高剂量处理后,SOD活性升高(P<0.05),MDA含量及LDH活力均下降(P<0.05)。香叶木苷中剂量和香叶木苷高剂量使p-Nrf2、PGC-1α、TFAM蛋白表达水平均升高(P<0.05)。结论:香叶木苷可促进心肌细胞生长,抑制其凋亡,减轻心肌损伤,缓解异丙肾上腺素诱导的大鼠心脏功能紊乱和氧化应激,可能与Nrf2磷酸化有关。

Objective:Myocardial injury damages normal cardiac structure and leads to cardiac dysfunction.Oxidative stress is considered to be a key mechanism for the progression of cardiac injury and dysfunction.This study explored the effects of diosmin on isoproterenol-induced cardiac dysfunction and oxidative stress in rats.Methods:Isoproterenol-induced myocardial injury model was established by subcutaneous injection of isoproterenol.After successful modeling,the rats were randomly divided into low-dose group,medium dose group and high-dose group.The low,medium and high-dose groups were given orally by gavage(5,10,20 mg/g).Administration once a day.Continuous administration for 10 weeks.Heart rate(HR) was measured and left ventricular systolic pressure(LVSP) and left ventricular ejection fraction(LVEF) were recorded by the BL-420 F biofunctional experimental system.The content of creatine kinase isoenzyme(CK-MB),CK,cardiac troponin I(cTnI) was detected by enzyme linked immunosorbent assay(ELISA).HE staining was used to observe the arrangement of myocardial tissue structure.Immunohistochemistry was used to detect the expression of Ki67 in myocardial tissue of each group.The contents of malondialdehyde(MDA),superoxide dismutase(SOD) and lactate dehydrogenase(LDH) were detected by the kit.Western blotting was used to detect the protein expression of BCL2-associated X protein(Bax),B-cell lymphoma-2(Bcl-2),cysteinyl aspartate specific proteinase(Caspase-3),survivin,Nrf2,p-Nrf2、peroxisome proliferator-activated receptorγcoactivator-1(PGC-1α) and mitochondrial transcription factor A(TFAM).Results:Medium and high doses of diosmin significantly increased HR and increased LVSP and LVEF levels(P<0.05).The contents of CK-Mb,cTnI in serum of rats were reduced after the treatment of middle and high doses of diosmin(P<0.05).Medium and high doses of diosmin alleviated isoproterenol-induced myocardial damage.After treatment with medium and high doses of diosmin,the number of Ki67 positive cells in cardiomyocytes was increased(P<0.05).The medium and high doses of diosmin promoted the expression of Survivin and inhibited the expression of Bax/Bcl and Caspase-3(P<0.05).After treatment with medium and high doses of diosmin,SOD activity was increased(P<0.05),MDA content and LDH activity were significantly decreased(P<0.05).The protein expression levels of p-Nrf2,PGC-1α and TFAM were increased by medium and high doses of diosmin(P<0.05).Conclusion:Diosmin can promote the growth of cardiomyocytes,inhibit their apoptosis,reduce myocardial injury,relieve the cardiac dysfunction and oxidative stress induced by isoproterenol in rats,indicating that isassociated with the phosphorylation of Nrf2.