【作者】 林葆菁；

【导师】 刘唐威；

【作者基本信息】 广西医科大学 ， 内科学， 2009， 博士

【摘要】 背景慢性心力衰竭(CHF)是一种复杂的临床综合征,是各种心脏病的严重阶段,也是主要的死亡原因。近年来,对心力衰竭的治疗已有很大进步,但整体上看,因心力衰竭而死亡的患者数目仍在逐步上升。通过大量的临床研究证实了ACEI和β受体阻滞剂是治疗心衰的有效药物,ACEI和β阻滞剂业已成为心衰治疗的基础用药,使心衰病人的临床预后有了极大改善。基于目前心衰的死亡率仍比较高的事实,寻找能进一步改善心力衰竭的其他药物的研究具有极其重要的意义。非洲裔美国人心衰实验(African-American Heart Failure Trial,A-HeFT)研究在标准心衰治疗的基础上加用固定剂量的肼苯哒嗪(Hydralazine,HYD)+硝酸异山梨醇酯(Isosorbide dinitrate,ISDN)复合制剂,与未用这两个药物的安慰剂组对比多项指标显示病人心力衰竭情况明显改善。由于这两个药物被传统认为是血管扩张剂,能降低血压,而在实验的受试人群中高血压所占的比例较大,这种治疗方案是否能对非高血压所致的心衰,如心肌病导致的心衰也能获得同样的效果?近年研究显示,内皮功能障碍是多种心血管疾病的危险因素,内皮功能障碍在心衰的发病过程中起着十分重要的作用。从现在研究看来,ISDN在体内主要是转变为一氧化氮(NO)起药理作用,提高NO水平。研究发现HYD是一种抗氧化剂,可清除氧自由基,减轻氧化应激反应。HYD+ISDN的作用是否由于两者通过增加NO、抗氧化,改善心衰时内皮功能紊乱起作用仍未清楚。目的本实验旨在观察,在使用ACEI和β阻滞剂基础上加用HYD+ISDN,用以治疗阿霉素(Adriamycin,ADR)致大鼠心衰的疗效。并观察该治疗方案对大鼠心衰时内皮功能和氧自由基清除能力的影响。方法120只Wistar大鼠随机分成两组,模型组大鼠腹腔注射ADR,空白组给予生理盐水(NS)。模型组存活大鼠再随机分为安慰剂对照组、阳性对照组、实验组,分别给予NS、ACEI+β阻滞剂、ACEI+β阻滞剂+HYD+ISDN。干预6周后,经心脏彩色超声多普勒、血清B型脑钠肽(BNP)测定、有创动脉压(IABP)、大鼠生成状况及心肌组织HE染色,以评价药物疗效。组织总NO含量、内皮型一氧化氮合成酶(eNOS)及内皮素-1(ET-1) mRNA水平(采用逆转录聚合酶链反应)和蛋白水平(蛋白免疫印记法)以评估内皮功能状况;血清和组织丙二醛(MDA)含量,以评估对体内氧自由基的清除能力。结果⑴实验组大鼠腹腔注射ADR后,模型组左室射血分数(LVEF)均低于正常组(P<0.05),左室收缩末径(LVESD)、左室舒张末径(LVEDD)均较正常组升高(P<0.05)。⑵药物干预后,与安慰剂对照组比较,实验组与阳性对照组的LVESD、LVEDD下降(P<0.05),LVEF增加(P<0.05),BNP下降(P<0.05)。实验组较阳性对照组有好转趋势,但并没有统计学意义(P>0.05)。⑶实验组和阳性对照组存活期均长于安慰剂对照组(P<0.05),但两组间存活期没有差异(P>0.05)。⑷实验组与阳性对照组的血压没有差异(P>0.05)。⑸实验组和阳性对照组总NO量均较安慰剂对照组增高(P<0.05),实验组增高更明显(P<0.05);实验组和阳性对照组均上调了eNOS mRNA和蛋白水平(P<0.05),但两组间没有差异(P>0.05);实验组和阳性对照组治疗后,均下调了ET-1 mRNA和蛋白水平(P<0.05),但两组间没有显著性差异(P>0.05)。⑹与安慰剂对照组相比,实验组和阳性对照组都降低了组织和血清中MDA的含量(P<0.05),实验组降低更明显(P<0.05)。结论⑴在ADR诱导的大鼠心衰模型中,在ACEI和β阻滞剂基础上加用HYD+ISDN干预6周,可观察到大鼠生存状况、心功能有改善的趋势,但是与阳性对照组相比没有统计学意义。考虑这跟观察时间较短有关。⑵HYD+ISDN治疗心衰的附加效益可能是通过增加NO的含量、清除氧自由基,改善内皮功能来起到治疗心衰的作用。更多还原

【Abstract】 Background: Chronic heart failure (CHF) is a complex clinical syndrome. It is the severe phase of cardiovascular disease and also the primary cause of death. In recent years a great deal of progress has been made in the treatment of heart failure. But the number of deaths from heart failure still increased steadily despite the advance in treatments. A large number of clinical studies confirmed that the angiotensin-converting-enzyme inhibitors (ACEI) andβ-blockers are the effective and the basic drugs for heart failure. ACEIs andβ-blockers improved the prognosis of patients with heart failure. Based on the fact that mortality rate due to heart failure is still at a high level, how to treat heart failure more effectively is an urgent problem today. Recently, African American Heart Failure Trial(A-HeFT) confirmed notable effects of hydralazine and isosorbide dinitrate combined treatment (HYD+ISDN) in African American patients with chronic heart failure on the basis of routine therapeutic strategy. There are many patients with CHF developed from hypertension in this trial. Is the benefit due to drug’s particular effect of reducing blood pressure? Does this strategy have any effect on non-hypertension-induced heart failure patients,such as cardiomyopathy? Recent studies have shown that endothelial dysfunction is a risk factor of cardiovascular disease. Endothelial dysfunction plays an important role in the pathogenesis of heart failure. ISDN is a NO donor. HYD is an antioxidant reducing oxidant stress and inhibiting the breakdown of nitric oxide.Whether HYD+ISDN improve endothelial dysfunction in heart failure mediated by nitric oxide and anti-oxidation is still unclear.Objective:We study the effect of HYD+ISDN in rats with adriamycin-induced heart failure already treated with ACEI andβ-blocker. We also observe the effect of HYD+ISDN on endothelial function and its ability of oxygen free radical scavenging in rats with heart failure.Methods:120 Wistar rats were randomly divided into 2 groups: control group (10) and study group (110). In the study group adriamycin (ADR) was injected intraperitoneal to create a heart failure model. 70 rats survived in the study group, and then were randomly divided into three groups: treated group (n=24), positive control group (n=23),placebo control group (n=23). Each group of rats were treated with one of the following combined drugs for 6 weeks: perindopril+bisoprolol+HYD+ISDN, perindopril+bisoprolol, normal saline. The efficacy of drugs was evaluated by echocardiography, serum B-type natriuretic peptide(BNP), invasive arterial blood pressure(IABP) and histopathological stain. Endothelial function was assessed by total NO concentration, endothelial nitric oxide synthase (eNOS) and endothelin-1(ET-1) mRNA (determined by reverse transcription polymerase chain reaction) and protein level (determined by western blot). Serum and tissue malondialdehyde was detected to decide the ability of scavenging oxygen free radicals.Results:⑴After intraperitoneal injection of ADR, left ventricular ejection fraction(LVEF) in rats of the treated group was lower (P<0.05) and left ventricular end systolic diameter(LVESD) and left ventricular end diastolic diameter(LVEDD) were higher (P<0.05).⑵After the drugs intervention: BNP, LVESD and LVEDD decreased (P <0.05) and LVEF increased (P <0.05) in rats of both the treated group and the positive control group compared with those in placebo control group. The treated group showed a trend of improvement, but no statistic difference was found between the treated group and the positive control group.⑶The treated group and the positive control group survived longer than the placebo control group (P<0.05), but there were no significant difference between the first two groups.⑷No difference of IABP was found between the treated group and the positive control group(P>0.05).⑸Compared with the placebo control group, total NO concentration increased in the treated group and the positive control group (P<0.05). Increase in the treated group was more significant (P<0.05). The expression of eNOS mRNA and protein were up-regulated (P<0.05) and ET-1 mRNA and protein expression were down-regulated in the treated group and the positive control group (P<0.05). ET-1 mRNA, eNOS and protein expression in the positive control group and the treated group had no significant difference (P>0.05).⑹Compared with the placebo control group, the treated group and the positive control group reduced the tissue and serum of malondialdehyde (MDA) level(P<0.05). Reduction in the treated group was more significant (P<0.05).Conclusions:⑴The use of HYD+ISDN in rats with adriamycin-induced heart failure, treated prior with ACEI andβ-blocker showed a trend of improvement on survival and cardiac function. But there were no statistical significance possibly due to short treatment duration.⑵HYD+ISDN therapy showed extra improvement of heart failure by increasing the content of NO, scavenging oxygen free radicals and improving endothelial function.更多还原