瓜蒌对心梗后心衰大鼠心功能及心肌细胞凋亡的影响

<正>瓜蒌是一味止咳化痰平喘中药,目前对其研究主要集中于瓜蒌皮药理作用的研究~([1-3]),因此,本文采用全瓜蒌考察其对心梗后心衰大鼠心功能及心肌细胞凋亡的影响,以期为全瓜蒌的深入研究与临床应用提供借鉴。1材料与方法1.1材料1.1.1实验动物100只♂SD大鼠,体质量(230±20)g,购于北京华阜康生物科技有限公司,许可证号:SCXK(京)     

硫化氢抑制离体灌流大鼠急性心肌缺血所致心肌细胞凋亡研究

目的探讨硫化氢(H2S)能否抑制离体灌流大鼠急性心肌缺血所致细胞凋亡。方法应用Langendorff离体灌流大鼠心脏复制急性心肌缺血损伤模型,结扎冠状动脉,心肌缺血4 h。40只♂SD大鼠随机分为5组(n=8):假手术组(Sham),缺血组(Ischemia)和硫氢化钠(NaHS)5、10、20μmol·L-1组。HE染色分析左心室心肌细胞组织形态学变化,TUNEL方法检测细胞凋亡,Western blot检测各组caspase-3和Cyt-C的蛋白表达。结果离体心肌缺血4 h后,光镜下可见心肌较大范围局灶性病变,细胞呈凝固性或带状坏死;心肌细胞凋亡率及心肌组织中caspase-3和Cyt-C蛋白表达明显升高。经NaHS 2 h处理,NaHS组光镜下心肌细胞结构清晰,心肌病变的程度明显减轻,大鼠心肌组织Cyt-C蛋白表达明显低于Ischemia组;NaHS 10、20μmol·L-1组心肌细胞凋亡率及心肌组织caspase-3蛋白表达明显低于Ischemia组。结论 H2S可通过抑制细胞凋亡对离体灌流大鼠急性心肌缺血发挥一定保护作用。     

Transient drug-induced myocardial dysfunction is not ameliorated by PGI2 in dogs

Prostacyclin (PGI2), a potent vasodilatory substance that effectively inhibits platelet aggregation is under clinical investigation for the treatment of angina pectoris. We studied the effects of PGI2 on transient drug-induced myocardial dysfunction in anesthetized, thoracotomized dogs. Regional myocardial function was assessed using two pairs of piezoelectric transducers and a multidimensional measuring gauge; one pair was implanted in the distribution area of the left circumflex branch (LCX) and the other in the distribution area of the descending branch (LAD) of the left coronary artery. After intravenous injection of isoproterenol (ISO), which led to an increase in systolic shortening in the LCX and LAD areas, a critical stenosis was performed on the LCX and maintained at this level. Intravenous ISO injection now induced regional dysfunction in the LCX-dependent segment with the occurrence of systolic bulging. Infusion of PGI2 at a dosage of 100 ng/kg/min caused a decrease in arterial blood pressure and an increase in heart rate, but had no effect on regional myocardial function. ISO-induced myocardial dysfunction in the critically stenosed LCX segment, which was observed before PGI2 administration, was not ameliorated, but rather aggravated, by PGI2. It may be concluded that PGI2 does not improve normal or ISO-stimulated myocardial function in pressure-dependent perfused areas of the heart.     

比索洛尔对慢性心力衰竭大鼠心肌细胞凋亡及心功能的保护作用

目的研究比索洛尔(Biso)对腹主动脉结扎所致慢性心力衰竭大鼠心肌细胞凋亡和心功能的保护作用。方法 SD大鼠40只,随机分为4组,即腹主动脉缩窄(COA)+Vehicle组;COA+Biso组;假手术(Sham)+Vehicle组;Sham+Biso组。Biso干预8周后采用超声心动图和心室插管法评估各组大鼠的心功能,计算左、右心室质量指数(LVMI、RVMI),高敏酶联免疫吸附试验(ELISA)检测血浆去甲肾上腺素(NE)水平,放射免疫法(RIA)检测血浆血管紧张素Ⅱ,AngⅡ水平。用琼脂糖凝胶电泳和TUNEL法观察心肌细胞的凋亡状态,通过反转录聚合酶链反应(RT-PCR)检测凋亡相关基因的表达变化。结果与COA+Vehicle组相比,COA+Biso组大鼠心功能明显改善[LVEF:COA+Biso组:(67±8)%比COA+Vehicle组:(43±8)%,P<0.05],血浆NE[COA+Biso:(570±41)pg/ml比COA+Vehicle:(908±75)pg/ml,P<0.05]和AngⅡ[COA+Biso:(357±49)pg/ml比COA+Vehicle:(476±51)pg/ml,P<0.05]水平降低,未出现细胞凋亡特有的"DNAladder"现象,TUNEL检测凋亡指数减少[COA+Biso:(9.6±0.5)%比COA+Vehicle:(7.2±0.6)%,P<0.05],RT-PCR检测Bax/Bcl-2比例降低[COA+Biso:(114±9)%比COA+Vehi-cle:(137±9)%,P<0.05]。与Sham+Vehicle组相比,COA+Vehicle组大鼠各项心功能指标明显恶化,心肌细胞凋亡较为严重。结论 Biso可降低血浆NE和AngⅡ水平,并通过阻断NE与β1肾上腺素能受体(β1-AR)结合,抑制凋亡相关通路,从而抑制慢性心力衰竭大鼠心肌细胞凋亡,改善心功能,延缓心力衰竭进展。     

异丙基肾上腺素充血性心力衰竭大鼠模型心肌细胞凋亡的改变

目的建立异丙基肾上腺素诱导SD大鼠充血性心力衰竭模型,观察大鼠心肌细胞凋亡的变化。方法实验选用雄性SD大鼠60只,随机分为对照组10只、心衰组50只;用ISO（170mg/kg）对雄性SD大鼠皮下注射2次,6周后应用超声心动图检测,以左心室射血分数（LVEF）≤45%确定造模成功,18周使用左心导管进行血流动力学检查,取心脏观察左心室重量指数等病理形态学特征。并利用琼脂糖凝胶电泳法检测DNA断片化,和免疫印迹分析法检测Bcl-2,Bax,caspase-9和caspase-3的表达。结果与对照组相比,模型组HR、LVEDP、LVWI显著升高（P〈0.01）,LVSP明显降低（P〈0.01）和左心室压力上升/下降最大数率（±dp/dtmax）明显降低（P〈0.01）,左心室重量指数明显增加（P〈0.01）,心肌DNA断片比例升高,Bax、caspase-9和caspase-3表达升高,而Bcl-2表达下降。结论异丙基肾上腺素可诱导大鼠心衰模型,该作用可能与心肌细胞凋亡增加有关。     

硫化氢对急性缺血所致心肌细胞凋亡的影响

目的观察H2S对急性缺血所致大鼠心肌细胞凋亡的影响。方法健康成年♂SD大鼠(270±20)g,随机分为:假手术组、缺血组、缺血+NaHS低、中、高剂量组。麻醉大鼠,结扎左冠状动脉前降支,NaHS低、中、高剂量组分别于缺血3 h时腹腔注射0.78、1.56和3.12 mg·kg-1的NaHS,缺血组注射等容量的生理盐水,假手术组只穿线不结扎。各组大鼠均于缺血6 h时经颈总动脉取血迅速开胸取心脏,流式细胞术检测心肌组织细胞凋亡率,Western blot法检测caspase-3蛋白的表达,免疫组化法检测Bcl-2和Bax蛋白的表达,HE染色观察心肌组织学变化。结果大鼠心肌缺血6 h后,心肌细胞凋亡率、caspase-3和Bax表达阳性细胞数百分率明显升高,Bcl-2表达阳性细胞数百分率降低。缺血3 h治疗3 h时,NaHS 3个剂量组大鼠心肌细胞凋亡率、caspase-3和Bax表达阳性细胞数百分率明显低于缺血组,Bcl-2蛋白表达、Bcl-2/Bax比值高于缺血组。组织形态学变化显示,假手术组大鼠心肌细胞排列整齐,着色均匀,缺血组大鼠心脏部分区域心肌纤维横纹不齐或消失,核偏移甚至裂解消失,有炎性因子渗出,NaHS 3个剂量组大鼠心肌细胞损伤程度较缺血组明显减轻。结论硫化氢对大鼠急性缺血心肌具有一定的保护作用,上调Bcl-2的表达,下调Bax表达,抑制细胞凋亡可能是其重要保护作用机制。     

褪黑素对心力衰竭大鼠心肌细胞凋亡及氧化应激的影响

目的：观察褪黑素（melatonin,MT）对心力衰竭大鼠的心肌细胞凋亡及氧化应激的影响,并初步探讨其影响机制。方法：将52只雄性SD大鼠随机分为3组。MT组及异丙肾上腺素组（ISO组）各20只,对照组12只。MT组及ISO组给予ISO皮下多点注射ISO建立心衰模型,造模成功后MT组给予MT治疗,ISO组不给予MT治疗;对照组不给予任何处置。8周后,随机从各组选取存活大鼠各10只,进行心脏超声检查,并测定心肌组织SOD、GSH-PX活性及MDA的含量;原位末端标记法（TUNEL）检测心肌细胞凋亡指数。结果：与对照组大鼠比较,ISO组及MT组大鼠LVEDD、LVESD明显扩大（P〈0.05或P〈0.01）,LVEF、FS明显降低（P〈0.01）,心肌细胞凋亡指数升高（P〈0.01）,心肌组织MDA含量升高（P〈0.01）,SOD、GSH-Px活性均有显著性下降（P〈0.05或0.01）;与ISO组大鼠比较,MT组大鼠LVEDD、LVESD明显减小（P〈0.05）,LVEF、FS明显增加（P〈0.05）,心肌细胞凋亡指数减低（P〈0.01）,心肌组织MDA含量下降（P〈0.05）,SOD、GSH-Px活性亦有明显升高（P〈0.05）。结论：MT能够改善心力衰竭大鼠心肌组织的氧化应激反应及心肌细胞凋亡,并具有改善心脏功能的作用。     

Liguzinediol improved the heart function and inhibited myocardial cell apoptosis in rats with heart failure

Aim:

Liguzinediol is a novel derivative of ligustrazine isolated from the traditional Chinese medicine Chuanxiong (Ligusticum wallichii Franch), and produces significant positive inotropic effect in isolated rat hearts. In this study we investigated the effects of liguzinediol on a rat model of heart failure.

Methods:

To induce heart failure, male SD rats were injected with doxorubicin (DOX, 2 mg/kg, ip) once a week for 4 weeks. Then the rats were administered with liguzinediol (5, 10, 20 mg·kg⁻¹·d⁻¹, po) for 2 weeks. Hemodynamic examination was conducted to evaluate heart function. Myocardial cell apoptosis was examined morphologically. The expression of related genes and proteins were analyzed using immunohistochemical staining and Western blot assays, respectively.

Results:

Oral administration of liguzinediol dose-dependently improved the heart function in DOX-treated rats. Electron microscopy revealed that liguzinediol (10 mg·kg⁻¹·d⁻¹) markedly attenuated DOX-induced injury of cardiomyocytes, and decreased the number of apoptotic bodies in cardiomyocytes. Furthermore, liguzinediol significantly decreased Bax protein level, and increased Bcl-2 protein level in cardiomyocytes of DOX-treated rats, led to an increase in the ratio of Bcl-2/Bax. Moreover, liguzinediol significantly decreased the expression of both cleaved caspase-3 and NF-κB in cardiomyocytes of DOX-treated rats. Administration of digitalis (0.0225 mg·kg⁻¹·d⁻¹) also markedly improved the heart function and the morphology of cardiomyocytes in DOX-treated rats.

Conclusion:

Liguzinediol improves the heart function and inhibits myocardial cell apoptosis in the rat model of heart failure, which is associated with regulating Bcl-2, Bax, caspase-3 and NF-κB expression.     

精胺预处理对离体灌流大鼠心肌缺血/再灌注损伤及细胞凋亡的影响

目的探讨精胺预处理对离体灌流大鼠心肌缺血/再灌注损伤的影响及其可能的抗凋亡作用。方法应用Langehdorff离体灌流大鼠心脏复制模拟心肌缺血/再灌注损伤模型。24只大鼠随机分为3组,每组8只:对照组(Con-trol)、缺血/再灌注组(IR)、精胺干预组(Spermine)。比色法测定冠脉流出液中乳酸脱氢酶(LDH)活力,心肌组织中超氧化物歧化酶(SOD)活性及心肌丙二醛(MDA)含量;多导生理记录系统记录心脏功能;HE染色光镜下观察心肌形态学变化;三苯基氯化四氮唑(TTC)染色检测心肌梗死面积;透射电镜和TUNEL方法检测细胞凋亡;免疫组化检测心肌Fas与Bcl-2蛋白的表达。结果 (1)与对照组比,IR组冠脉LDH漏出明显增多、心肌组织中MDA水平增加、SOD活性降低(P<0.01);心功能明显下降(LVDP,HR,CF均低于对照组,P<0.05);光镜下可见心肌细胞呈凝固性或带状坏死。与Control组比,IR组心肌梗死面积及心肌细胞凋亡率明显增加(P<0.01);心肌Fas蛋白表达上调,Bcl-2蛋白表达下调。透射电镜下心肌细胞核染色质浓缩、凝聚且边集,染色质在核膜周边聚集形成新月形,线粒体嵴排列紊乱。(2)与IR组比,Spermine组冠脉LDH漏出减少,心肌组织中MDA减少,SOD增加(P<0.01);心功能有明显改善(LVDP,HR,CF均明显高于IR组,P<0.05);光镜下心肌细胞结构清晰。Spermine组与IR组比心肌梗死面积及心肌细胞凋亡率均明显降低(P<0.01);心肌Fas蛋白表达下调,Bcl-2蛋白表达上调;电镜下可见心肌肌节结构清晰,线粒体嵴完整、基质致密,未见核染色质凝聚。结论外源性精胺能明显减轻离体灌流大鼠心肌缺血/再灌注损伤,其机制可能与精胺抑制细胞凋亡有关。     

阿托伐他汀对老年非缺血性心力衰竭患者心功能的影响

目的观察阿托伐他汀对老年非缺血性心力衰竭患者血浆肿瘤坏死因子-α(TNF-α)、白细胞介素-6(IL-6)、基质金属蛋白酶-9(MMP-9)和Ⅰ型胶原羧基端交联肽(CITP)水平的影响,探讨他汀类药物减少或延缓老年非缺血性心力衰竭发生和发展的可能机制。方法选择经冠状动脉造影证实的老年非缺血性心力衰竭患者38例作为研究对象,随机分为他汀类治疗组(阿托伐他汀10mg/d)及常规治疗组,每组19例。随访6个月,测定治疗前后患者血清TNF-α、IL-6、MMP-9和CITP的水平,并通过超声心动图观察治疗前后左心室射血分数(LVEF)及左心室大小。结果治疗过程中有1例患者因转氨酶增高停用阿托伐他汀治疗。2组治疗后血清TNF-α、IL-6、MMP-9和CITP水平与治疗前相比均下降(P<0.05)。治疗后治疗组血清TNF-α、IL-6、MMP9和CITP水平及LVEF明显低于对照组(P<0.01)。结论阿托伐他汀可以降低非缺血性心力衰竭患者血清TNF-α、IL-6、MMP-9和CITP的水平,延缓老年非缺血性心力衰竭的发生发展。     

The effects of nitroglycerin on exercise-induced regional myocardial contractile dysfunction are not diminished by pretreatment with dihydroergotamine.

1 Because controversy exists regarding the effects of dihydroergotamine (DHE) on the performance of underperfused myocardium, the effects of DHE were investigated in a model of exercise-induced regional myocardial dysfunction in conscious dogs. 2 We also investigated a possible functional antagonism between DHE and nitroglycerin that might reduce the latter drug's antianginal efficacy. 3 Investigations were carried out in conscious dogs. After stenosis of the circumflex branch of the left coronary artery that minimally affected resting myocardial function, treadmill exercise induced transient regional contractile dysfunction. Heart rate, arterial blood pressure, left ventricular dp/dtmax and left ventricular end-diastolic pressure were registered. Regional contractile performance was assessed by ultrasonic distance measurement in the underperfused and in a normally perfused area. 4 DHE (5 micrograms kg-1, i.v.) induced a decrease in left ventricular dp/dtmax at rest and during exercise. DHE did not cause a deterioration in contractile function in the ischaemic myocardium, but led to a slight although not significant improvement in regional myocardial function. 5 After pretreatment with DHE, infusion of nitroglycerin (15 micrograms kg-1, i.v.) induced an improvement in the underperfused myocardial area during treadmill exercise, accompanied by a decrease in diastolic arterial pressure and left ventricular end-diastolic pressure and an increase in left ventricular dp/dtmax. 6 These results suggest that DHE will not worsen exercise-induced angina pectoris, and that the antianginal efficacy of nitroglycerin will not be neutralized by pretreatment with DHE.     

Propranolol ameliorates exercise-induced regional myocardial dysfunction in dogs

The effects of propranolol (0.5 mg/kg) on exercise-induced regional myocardial dysfunction were investigated in an animal model with limited coronary reserve. Limited coronary reserve was accomplished in conscious, chronically instrumented dogs by external filling of a hydraulic cuff occluder placed on a coronary vessel which did not impair resting myocardial function but induced severe dysfunction during treadmill exercise. Propranolol led to a distinct reduction of heart rate, myocardial contractility and systolic blood pressure, thereby ameliorating exercise-induced regional myocardial dysfunction.     

Hypoalgesia induced by counter-irritation is not affected by pCPA pretreatment

In a previous work (4), it has been described that a noxious visceral stimulation through the intraperitoneal injection of acetic acid (ipAA) induced a transient and low magnitude increase in tail-flick latencies, but a marked increase in the threshold for vocalization and hot-plate latencies. In the present work, this phenomenon of hypoalgesia through counter-irritation was investigated in intact rats with or without pretreatment with the potent serotonin depletor parachlorophenylalanine (pCPA). Three behavioural tests were performed. In two tests (tail flick, vocalization induced by transcutaneous electrical stimulation of the tail), pCPA pretreatment induced an increase of baseline levels, before IP injection of the allogenic agent (ipAA). In the third test, pCPA pretreatment had no effects on jump latencies. Parachlorophenylalanine pretreatment had no effect upon hypoalgesic actions of IP injected AA in all three tests. These results are discussed in terms of pCPA's differential effects upon basal nociception and analgesia induced by various heterotopic nociceptive stimulations.     

Improvement of chronic heart failure by dexamethasone is not associated with downregulation of leptin in rats

AIM: To demonstrate the hypothesis that dexamethasone (Dex) could improve chronic heart failure (CHF) by inhibiting the downstream signaling transduction of leptin but had no influence on the upregulation of leptin and its receptor in myocardium. METHODS: CHF was induced by left coronary artery ligation for 6 weeks. CHF rats were treated with Dex 50 mg.kg/d. Hemodynamics, histology, reactive oxygen species (ROS)-related parameters, and leptin concentrations in serum were measured. The mRNA expression of matrix metalloproteinases (MMP)2/9, tissue inhibitor of metalloproteinases (TIMP)1/2, tumor necrosis factor (TNF)-alpha, and OB-Rb were measured by RT-PCR. RESULTS: In the CHF rats, hemodynamic functions were deteriorated, which was accompanied with myocardium remodeling and histological changes. CHF rats showed hyperleptinemia and excessive ROS in the serum, and the upregulation of MMP-2/9, TNF-alpha, and leptin receptor mRNA and downregulation of TIMP-1/2 mRNA in the myocardium compared with the sham operation group. Dex treatment significantly ameliorated CHF in association with the reversion of the abnormalities of MMP-2/9, TIMP-1/2, TNF-alpha, and ROS. But Dex had no influence on the hyperleptinemia and the upregulated leptin and its receptor in the myocardium during CHF. CONCLUSION: Dex improves CHF by inhibiting TNF-alpha, MMP-2, MMP-9, and ROS. Dex had no effects on upregulated leptin and its receptor expression and hyperleptinemia induced by CHF.     

螺内酯对心肌梗死后心肌细胞凋亡和增殖的影响

目的 探讨螺内酯对心肌梗死后细胞凋亡和增殖的影响.方法 45只SD大鼠随机分为3组：假手术（SHAM）组、心肌梗死（Myocardial infarction,MI）组和心肌梗死后螺内酯（Spironolactone,SPI）干预组.测量左心室功能,光镜观察标本病理形态改变,缺口末端标记法（TUNEL）检测细胞凋亡程度,免疫组化观察细胞增殖核抗原（PCNA）表达.结果 MI组心功能较SHAM组明显下降,SPI组较MI组改善;SHAM组心肌结构完整,MI组心肌结构损害严重,SPI组心肌结构损害较轻;与SHAM组相比,MI组凋亡细胞数显著增加;与MI组相比,SPI组心肌细胞凋亡数显著减少（P＜0.01）.与SHAM组相比,MI组PCNA表达显著增加;与MI组相比,SPI组PCNA表达无明显差异 结论 螺内酯改善心室重构和心力衰竭主要通过抑制细胞凋亡而非心肌细胞的增殖.     

Diastolic dysfunction in congestive heart failure.

The available literature on the evaluation of diastolic function, the importance of diastolic dysfunction in congestive heart failure (CHF), and the effects of therapeutic agents on diastolic dysfunction are summarized. The normal cardiac cycle consists of two components: systole (contraction; ventricular emptying) and diastole (dilation; ventricular filling). Recent studies have shown that 30-40% of patients with CHF have normal systolic function; the majority of these patients have diastolic dysfunction as the underlying disorder. As a result, the role of diastolic dysfunction in CHF is currently an area of interest for researchers. The two primary causes of diastolic dysfunction are left ventricular hypertrophy and ischemic heart disease. Patients with CHF caused by diastolic dysfunction and patients with CHF caused by systolic dysfunction have nearly identical clinical presentations. Therapy with diuretics, vasodilators, angiotensin-converting-enzyme inhibitors, beta-agonists, the partial beta-agonist xamoterol, phosphodiesterase III inhibitors, or calcium-channel blockers may be beneficial in patients with diastolic dysfunction. Therapy with digitalis glycosides would be of no benefit, and could theoretically be detrimental, in patients with predominant diastolic dysfunction. Available data indicate that beta blockers have neither an important beneficial effect nor an important detrimental effect on diastolic function. Continued studies into diastolic dysfunction and the diastolic properties of agents that are used in the treatment of CHF should enhance the understanding of this clinical syndrome and the drugs used to treat it.     

红景天苷对兔急性心肌缺血早期心肌细胞凋亡的影响

目的观察红景天苷（Sai）对兔急性心肌缺血早期心肌细胞凋亡的作用,探讨其可能的作用机制。方法新西兰白兔36只,随机分为生理盐水（NS）组和Sal组,分别以NS及Sal（200mg·kg^-1·d^-1）连续灌胃4周,结扎左冠状动脉前降支造成急性心肌缺血模型。各组分别于术后0、4．5、6h取左室心肌制备石蜡切片,TUNEL染色计数凋亡细胞;摘取心脏标本前采血检测血肌酸激酶同工酶MB（CK-MB）、肌钙蛋白I（cTnI）、一氧化氮（NO）、一氧化氮合酶（NOS）含量。结果①2组缺血4．5、6h血CK-MB、cTnI含量均较0h显著升高（P〈0．05）,且Sal组较NS组低,但无统计学意义（P〉0．05）。②2组急性心肌缺血早期不同时点（4．5h及6h）均可检出凋亡细胞,缺血4．5h凋亡细胞指数高于缺血6h,但无统计学意义（P〈0．05）;Sal组凋亡细胞指数较NS组明显减少（P〈0．05）。③同一时点2组血NO、NOS含量比较,Sal组高于NS组（P〈0．05）;但同组内各时点NO、NOS含量比较,差异无统计学意义（P〉0．05）。结论急性心肌缺血可诱导心肌细胞凋亡,Sal显著减少细胞凋亡并增加血NO含量,提示其抗凋亡作用可能与血NO含量增高有关。