骨髓间充质干细胞移植治疗大鼠扩张型心肌病

1泸州医学院附属医院急诊科,四川省泸州市 646000;2哈尔滨医科大学附属第二医院心内科,黑龙江省哈尔滨市  150000 背景：扩张型心肌病所致的心肌纤维化是心力衰竭的病理基础,目前药物治疗、介入治疗和外科手术均不能替代坏死心肌和彻底改善心脏功能。 目的：观察异体骨髓间充质干细胞移植对大鼠扩张型心肌病心脏功能的作用和心肌纤维化的影响。 方法：40只Wistar大鼠随机数字表法分为细胞移植组(n=15)、对照组(n=15)和空白组(n=10),前2组建立大鼠扩张型心肌病模型。造模成功4周后细胞移植组注射骨髓间充质干细胞悬液150 μL(含3×106个细胞),对照组和空白组注射等量培养液。 结果与结论：与空白组相比,细胞移植组和对照组移植前左室收缩末期内径增加,射血分数和缩短分数明显下降(P < 0.01);移植后4周,细胞移植组超声心动图检查和移植前相比,左室收缩末期内径下降、射血分数和缩短分数明显升高(P < 0.01)。细胞移植组心脏胶原的表达低于对照组(P < 0.05)。与对照组相比,其他2组基质金属蛋白酶2及基质金属蛋白酶9表达明显下降(P < 0.05)。提示骨髓间充质干细胞移植后可改善心肌纤维化及扩张型心肌病鼠的心脏功能。      

肌球蛋白诱导大鼠自身免疫性心肌炎不同时期心功能及心肌病理学变化

目的:观察心肌肌球蛋白诱导自身免疫性心肌炎不同时间实验大鼠心功能及心肌组织病理学动态变化。方法:以猪心肌肌球蛋白为致病性抗原,与完全弗氏佐剂等体积混合成乳浊液在实验第1天、8天、30天皮下注射免疫Lewis大鼠作为心肌炎组,以完全弗氏佐剂皮下注射大鼠作为对照组。HE染色和Masson染色观察两组大鼠初次免疫后第21天、30天、90天心肌病理变化,超声心动图检测两组大鼠初次免疫后第21天、30天、90天的射血分数(EF)、左室短轴缩短分数(FS)、左室舒张末内径(LVEDd)、左室收缩末内径(LV-EDs)及左心室后壁厚度(LVPW)等指标。结果:免疫后不同时间超声心动图检测提示心肌炎组大鼠心功能较对照组明显下降(EF:84.25±2.17%vs93.45±4.13%,P<0.05;FS:48.49±4.36%vs63.17±4.49%,P<0.05;LVEDd:3.66±0.35mmvs4.63±0.32mm,P<0.05)。免疫后第21天,HE染色见心肌炎组大鼠心肌细胞肿胀、变性、坏死及不同程度的急性炎性细胞浸润,至第90天心肌组织炎症减弱,间质出现纤维化,胶原容积分数升高,对照组大鼠未出现心肌炎症及纤维化。结论:心肌肌球蛋白可诱导大鼠实验性自身免疫性心肌炎,急性期心功能受损主要由心肌炎症引起,慢性期病理学改变主要表现为心肌纤维化。     

基于胰高血糖素样肽1受体及其下游信号探讨有氧运动对小鼠心梗模型心功能康复的影响

目的:探讨有氧运动训练(AET)对心肌梗死(MI)小鼠的心脏保护作用,并阐明其作用机制是否与胰高血糖素样肽1受体(GLP-1R)激活有关.方法:在实验1(研究AET对MI小鼠的心脏保护作用及对心脏组织中GLP-1R表达的影响)中,67只小鼠分为3组:假手术(sham)组(n=14)、MI组(n=28)和MI+AET组(...     

人羊膜上皮细胞静脉移植治疗大鼠心肌梗死

背景：人羊膜上皮细胞在体外适当诱导条件下可分化为心肌样细胞,可望成为细胞心肌成形术的种子细胞,但在心肌梗死原位是否能分化成心肌细胞值得探讨。 目的：探讨人羊膜上皮细胞移植在心肌梗死原位的分化及对心肌梗死后心室重构和心功能的影响。 方法：用胰酶消化分离人羊膜上皮细胞,行流式细胞仪检测和免疫组化染色以鉴定其表型特征。结扎SD大鼠左冠状动脉前降支以建立心肌梗死模型,实验分为人羊膜上皮细胞移植组、模型组及假手术组,人羊膜上皮细胞移植组于造模后1周经舌下静脉移植Brdu标记的人羊膜上皮细胞。移植后1,4,6周采用超声心动图检查心功能变化,应用苏木精-伊红和Masson染色观察心肌重构的变化,以免疫荧光双染色法检测人羊膜上皮细胞在心肌梗死区的植活与分化。 结果与结论：①所分离的人羊膜上皮细胞表达CD29、CD166、CD73和CK19,不表达CD44、CD34、CD45、CD80、CD86和HLA-DR。②人羊膜上皮细胞移植后6周,心肌梗死区仍可见Brdu标记的阳性细胞,表达心肌特异蛋白连接蛋白43、α-辅肌动蛋白和结蛋白。③移植组大鼠左心室纤维化程度明显低于模型组。④移植组大鼠射血分数、左室短轴缩短率显著高于模型组(P < 0.01);舒张期左室前壁厚度和收缩期左室前壁厚度也显著大于模型组(P < 0.05)。提示人羊膜上皮细胞在心肌梗死原位可分化为心肌细胞,可减缓心室重构并改善心脏功能。     

Renal function after myocardial infarction and cardiac arrest in rats: role of ANP-induced albuminuria?

Renal function was measured by clearance technique before and after acute myocardial infarction (MI) induced by left coronary artery ligation in male Sprague–Dawley rats. The animals were anaesthetized with halothane-nitrous oxide, paralysed with pancuronium and artificially ventilated. All parameters were stable throughout the experiment in sham-operated time control animals (n = 8). After MI, rats developed left ventricular dysfunction with increased left ventricular end-diastolic pressure and decreased mean arterial pressure. MI produced antidiuresis and antinatriuresis without changes in glomerular filtration rate (GFR), lithium clearance or renal albumin excretion (n = 8). The antidiuretic and antinatriuretic responses to MI were similar in rats with chronic bilateral renal denervation (n = 5). Three additional rats with chronic bilateral renal denervation had cardiac arrest and were resuscitated with cardiac massage, i.v. lidocaine and intracardiac adrenaline administration. These animals showed a transient increase in urine flow rate, sodium and albumin excretion with maximum 30–60 min after resuscitation, while GFR and lithium clearance were normal. Since cardiac ischaemia and sympathetic stimulation are strong stimuli for the release of atrial natriuretic peptide (ANP), we examined if ANP (0.25, 0.50, and 1.00 μg kg^?1 min^?1, n = 8 per dose) affects urinary albumin excretion. ANP increased dose-dependently the urine/plasma concentration ratio of albumin relative to inulin, which suggests that ANP increases the glomerular permeability for albumin. We conclude that MI causes stimulation of renal tubular sodium and water reabsorption by a mechanism which is independent of intact renal innervation. MI does not produce any change in renal albumin excretion in rats, but transient albuminuria may be observed in rats following cardiac arrest and/or manoeuvres used in cardiac resuscitation. Since ANP produces albuminuria, we speculate that ANP may be an important mediator of albuminuria in states with elevated plasma concentrations of ANP.     

神经调节蛋白1β与卡托普利对慢性心衰大鼠心肌纤维化及转化生长因子β1的影响

目的:探讨神经调节蛋白1β(neuregulin-1β,NRG-1β)与卡托普利联合应用对慢性心力衰竭大鼠心肌纤维化及转化生长因子β1(transforming growth factor-β1,TGF-β1)表达的影响。方法:将青年雄性SpragueDawley大鼠随机分为假手术组、心衰组、NRG组、卡托普利组和联合用药组,采用腹主动脉-下腔静脉穿刺造瘘法制备心衰模型。通过超声心动图评价大鼠心功能;Masson染色检测心肌纤维化程度,并计算胶原容积分数(collagen volume fraction,CVF);放射免疫法检测血浆中血管紧张素II(Ang II)的浓度;Western blot检测各组大鼠左心室心肌组织中TGF-β1和α-平滑肌肌动蛋白(α-SMA)的蛋白表达水平;透射电镜观察左室心肌的超微结构。结果:与心衰组比较,NRG组、卡托普利组及联合用药组左心室舒张末直径和心肌纤维化程度明显降低,射血分数明显升高(P0.05);TGF-β1和α-SMA蛋白表达明显降低(P0.05);电镜下显示,NRG组、卡托普利组及联合用药组心肌纤维化程度较心衰组明显减轻,而与NRG组和卡托普利组相比,联合用药组效果更加显著(P0.05)。结论:神经调节蛋白1β与卡托普利单用及联合应用均可有效改善心功能、抑制心肌纤维化,且联合用药的疗效优于单独用药。     

肾交感神经去除术对心肌肥厚和心肌纤维化的影响

 目的:观察肾交感神经去除术（renal sympathetic denervation, RDN）对心肌肥厚和心肌纤维化的影响,并探讨其可能机制。方法:选用12周龄的健康SD雄性大鼠60只,随机分为假手术组、假手术+RDN组、主动脉缩窄组、主动脉缩窄+RDN组,8周后用介入生理记录仪检测血流动力学和心功能指标,HE染色、苦味酸-天狼星红染色分别观察心肌肥厚和心肌纤维化情况,放射免疫分析法测量血浆肾上腺素浓度、肾素活性、血管紧张素II浓度及心脏血管紧张素II含量。结果:与主动脉缩窄组相比,RDN可显著改善主动脉缩窄大鼠心脏舒张功能［左室舒张末期压力（LVEDP）：(8.03±1.66) mmHg vs(15.77±2.14) mmHg;等容舒张期左室压力下降最大速率（-dp/dt）：(7 793±587) mmHg/s vs(6 353±475) mmHg/s;P＜0.01］、防止其心肌肥厚和纤维化［左心室重量指数：3.340±0.121 vs4.244±0.102;心肌细胞面积：(332.9±28.9) μm2 vs(401.6±33.2) μm2;胶原容积分数：7.76%±0.85% vs12.48%±1.82%;P＜0.01］。然而,RDN不能降低主动脉缩窄大鼠的血压（P＞0.05）。RDN导致主动脉缩窄大鼠的血浆肾上腺素浓度、肾素活性、血管紧张素II浓度及心脏血管紧张素II含量均明显减少（P＜0.01）。结论: RDN可以通过降低交感和肾素-血管紧张素系统活性直接抑制心肌肥厚和心肌纤维化,从而改善心脏功能。     

Lentivirus-mediated overexpression of angiotensin-(1-7) attenuated ischaemia-induced cardiac pathophysiology

Myocardial infarction (MI) results in cell death, development of interstitial fibrosis, ventricular wall thinning and ultimately, heart failure. Angiotensin-(1-7) [Ang-(1-7)] has been shown to provide cardioprotective effects. We hypothesize that lentivirus-mediated overexpression of Ang-(1-7) would protect the myocardium from ischaemic injury. A single bolus of 3.5 × 10(8) transducing units of lenti-Ang-(1-7) was injected into the left ventricle of 5-day-old male Sprague-Dawley rats. At 6 weeks of age, MI was induced by ligation of the left anterior descending coronary artery. Four weeks after the MI, echocardiography and haemodynamic parameters were measured to assess cardiac function. Postmyocardial infarction, rats showed significant decreases in fractional shortening and dP/dt (rate of rise of left ventricular pressure), increases in left ventricular end-diastolic pressure, and ventricular hypertrophy. Also, considerable upregulation of cardiac angiotensin-converting enzyme (ACE) mRNA was observed in these rats. Lentivirus-mediated cardiac overexpression of Ang-(1-7) not only prevented all these MI-induced impairments but also resulted in decreased myocardial wall thinning and an increased cardiac gene expression of ACE2 and bradykinin B2 receptor (BKR2). Furthermore, in vitro experiments using rat neonatal cardiac myocytes demonstrated protective effects of Ang-(1-7) against hypoxia-induced cell death. This beneficial effect was associated with decreased expression of inflammatory cytokines (tumour necrosis factor-α and interleukin-6) and increased gene expression of ACE2, BKR2 and interleukin-10. Our findings indicate that overexpression of Ang-(1-7) improves cardiac function and attenuates left ventricular remodelling post-MI. The protective effects of Ang-(1-7) appear to be mediated, at least in part, through modulation of the cardiac renin-angiotensin system and cytokine production.     

Changes in cardiovascular function on treatment of inhibitors of apoptotic signal transduction pathways in left ventricular remodeling after myocardial infarction.

INTRODUCTION: It has been suggested that apoptosis in cardiac remodeling after myocardial infarction (MI) occurs in cardiomyocytes and is critically involved in the process of postinfarct cardiac remodeling. We investigated the pathophysiological link between myocardial apoptosis and cardiovascular function by modulating apoptotic signal transduction pathways. METHODS: Either a caspase-3 inhibitor (CasI) or a calpain inhibitor (CalI) was administered immediately after MI in a rat model of MI. Blood pressure (BP), heart rate (HR), and blood flow velocity (BFV) were measured, and pressure-rate product (PRP) was calculated to estimate the changes in cardiovascular function (n=6 for each group). RESULTS: BFV showed no remarkable changes in any of the groups. Both systolic blood pressure (SBP) and HR changed significantly (P<.01) in the MI+CasI and MI+CalI groups at 1 day after MI and returned to control levels thereafter. In contrast, SBP and HR remained significantly (P<.01) altered in the MI group. PRP in the MI groups was significantly decreased (P<.05 in the MI and MI+CasI groups; P<.01 in the MI+CalI group) at 1 day after MI and returned to control levels at 4 days. CONCLUSION: This study suggests that inhibition of apoptosis during left ventricular remodeling ameliorates cardiovascular function in remodeled hearts.     

人脐带间充质干细胞分化为心肌细胞的实验研究

目的 探讨人脐带间充质干细胞(MSCs)在体外向心肌细胞分化的能力及移植后对急性心肌梗死大鼠心功能恢复的影响.方法 胶原酶胰酶消化法分离脐带MSCs.取第4-6代脐带干细胞,采用5-氮胞苷诱导,免疫组织化学和免疫荧光法对诱导后细胞进行鉴定.建立大鼠心肌梗死模型,并按完全随机法将其分为2组(n=10):细胞移植组和空白对照组.将培养脐带MSCs移植到大鼠梗死心肌周围,4周后,免疫荧光法鉴定移植细胞,并超声检测心功能改变.结果 体外诱导后,细胞的形态不断发生变化,诱导后的细胞表达心肌特异性α-肌动蛋白、肌球蛋白和肌钙蛋白T,阳性率在50%以上.细胞移植4周后,脐带MSCs在缺血心肌内存活并分化为心肌样细胞,心功能检测显示脐带MSCs移植组大鼠在移植后4周的左心室射血分数[(68.4±15.2)%]比对照组大鼠明显增加[(53.2±13.4)%,P＜0.05].结论 人脐带MSCs能够在体内外分化为心肌样细胞,并能促进心脏功能的恢复.     

厄贝沙坦联合美托洛尔治疗慢性充血性心衰的疗效观察

目的 观察厄贝沙坦联合美托洛尔治疗慢性充血性心衰的临床疗效。方法 选择我院自2015年3月~2016年5月收治68例慢性充血性心衰患者作为研究对象,将其随机分成对照组和研究组,每组34例。对照组采用厄贝沙坦治疗,研究组采用厄贝沙坦联合美托洛尔治疗,比较两组患者治疗前后的心率（HR）、收缩压（SBP）和舒张压（DBP）等血压水平以及左室舒张末内径（LVEDd）、左室收缩末内径（LVESd）和左室射血分数（LVEF）等左心功能指标,并统计和计算两组患者治疗期间的不良反应发生率及治疗的总有效率。结果 两组患者治疗前的心率、血压及各项左心功能水平对比,差异均无统计学意义（P＞0.05）。治疗期间,研究组与对照组的不良反应发生率对比差异统计学意义（P＞0.05）。治疗后,研究组的HR、DBP、DBP、LVEDd、LVESd均明显低于对照组,研究组的LVEF、治疗的总有效率明显高于对照组,两组对比差异有统计学意义（P＜0.05）。结论 对慢性充血性心衰患者采用厄贝沙坦联合美托洛尔治疗,不仅能有效改善患者的心率和血压水平,同时还能有效促进患者的左心功能恢复,患者治疗期间的毒副反应发生率较低,因此其是一组安全、高效的组合治疗药物。     

rAAV-mediated angiogenin gene transfer induces angiogenesis and modifies left ventricular remodeling in rats with myocardial infarction

In vitro studies have demonstrated that bovine angiogenin (ANG) significantly stimulates both the migration of endothelial cells and the formation of tubelike structures. The aim of this study was to explore whether ANG gene transfer could enhance vascularization, modify left ventricular remodeling, and attenuate cardiac dysfunction in rats with myocardial infarction (MI). We constructed a recombinant adeno-associated virus vector encoding the ANG gene (rAAV-ANG) and evaluated its angiogenic potential after regional transfection by intramyocardial injection immediately after left anterior descending artery ligation in rats. Four weeks after coronary artery ligation, rAAV-ANG transfection upregulated the myocardium ANG protein expression level in both normal and MI rats, and immunohistochemistry showed that the overexpressed ANG was distributed in the cytoplasm of cardiomyocytes. In rats with MI, rAAV-ANG treatment altered left ventricular remodeling, as indicated by a decrease in left ventricular end diastolic diameter, left ventricular end systolic diameter, cardiomyocyte diameter, ventricular weight to body weight ratio and interstitial fibrosis infiltration. We also found an increase in capillary density and partly restored cardiac function in the group receiving rAAV-ANG treatment. These results confirmed that in rats with MI, ANG gene transfer could induce angiogenesis, alter left ventricular remodeling, and attenuate cardiac dysfunction. This study provides a new choice of treatment for ischemic heart disease.     

当归对大鼠心肌梗死后心肌纤维化的影响及机制

目的： 观察转化生长因子-β1(TGF-β₁)、巨噬细胞在心肌梗死后心肌纤维化发生发展过程中的变化及当归的治疗作用，探讨心肌梗死后心肌纤维化的发生及当归的干预机制。 方法： 结扎SD大鼠冠脉前降支复制心肌梗死模型，随机分为假手术（sham）组、心肌梗死（MI）组和心肌梗死当归（MI+angelica）组。术后24 h开始给药，MI+angelica组腹腔注射当归（20 mL·kg^-1·d^-1，相当于生药10 g·kg^-1·d^-1），sham组和MI组腹腔注射等量生理盐水。于术后1、2、4周记录左室血流动力学改变，检测非梗死区心肌胶原含量、TGF-β₁及巨噬细胞的变化。 结果： ① MI组和MI+angelica组非梗死区心肌TGF-β₁及巨噬细胞阳性表达显著高于sham组（P<0.01），以1周的阳性表达为最高，但MI+angelica组低于MI组（P<0.01）；② 术后各时点MI组心功能受损，于术后2周和4周心肌胶原含量明显高于sham组（P<0.01）；术后4周MI+angelica组心功能损害轻于MI组，心肌胶原含量低于MI组（P< 0.01）。 结论： 当归通过抑制巨噬细胞在非梗死区的浸润、下调TGF-β₁的表达，阻断促纤维化发生的环节，减轻心肌梗死后非梗死区反应性胶原的过度沉积，防治心肌梗死后心肌纤维化，改善心脏功能。     

不同时间移植人脐血CD34+细胞可影响心肌梗死大鼠心功能及血管内皮细胞生长因子的分泌

背景：干细胞移植可以改善心脏功能,改善预后。 目的：观察不同时间经静脉移植人脐血CD34+细胞对心肌梗死大鼠心功能及细胞因子分泌的影响。 方法：结扎冠状动脉左前降支制备Wistar大鼠心肌梗死模型,于梗死后1,5,10 ,30 d经尾静脉注入0.5 mL人脐血CD34+细胞(实验组)或磷酸盐缓冲溶液(对照组)。 结果与结论：与对照组相比,梗死后5,10 d实验组大鼠左室射血分数明显升高(P < 0.05),左室收缩末内径明显减小(P < 0.05),左室后壁增厚率更高(P < 0.05),毛细血管密度明显增加(P < 0.05),且以梗死后10 d移植大鼠心功能改善效果最明显(P < 0.05)。梗死后10 d实验组心肌局部血管内皮细胞生长因子最高(P < 0.05)。说明大鼠心肌梗死后5,10 d经静脉移植脐血CD34⁺细胞可明显改善心功能,梗死后10 d移植血管内皮细胞生长因子分泌更多,血管生成更多,对心功能的改善更明显;同时说明脐血单个核细胞移植可能是通过增加血管内皮细胞生长因子分泌,提高毛细血管密度来改善心功能的。     

Local overexpression of HB-EGF exacerbates remodeling following myocardial infarction by activating noncardiomyocytes

Insulin-like growth factor (IGF), hepatocyte growth factor (HGF), and heparin-binding epidermal growth factor-like growth factor (HB-EGF) are cardiogenic and cardiohypertrophic growth factors. Although the therapeutic effects of IGF and HGF have been well demonstrated in injured hearts, it is uncertain whether natural upregulation of HB-EGF after myocardial infarction (MI) plays a beneficial or pathological role in the process of remodeling. To answer this question, we conducted adenoviral HB-EGF gene transduction in in vitro and in vivo injured heart models, allowing us to highlight and explore the HB-EGF-induced phenotypes. Overexpressed HB-EGF had no cytoprotective or additive death-inducible effect on Fas-induced apoptosis or oxidative stress injury in primary cultured mouse cardiomyocytes, although it significantly induced hypertrophy of cardiomyocytes and proliferation of cardiac fibroblasts. Locally overexpressed HB-EGF in the MI border area in rabbit hearts did not improve cardiac function or exhibit an angiogenic effect, and instead exacerbated remodeling at the subacute and chronic stages post-MI. Namely, it elevated the levels of apoptosis, fibrosis, and the accumulation of myofibroblasts and macrophages in the MI area, in addition to inducing left ventricular hypertrophy. Thus, upregulated HB-EGF plays a pathophysiological role in injured hearts in contrast to the therapeutic roles of IGF and HGF. These results imply that regulation of HB-EGF may be a therapeutic target for treating cardiac hypertrophy and fibrosis.     

大鼠急性心肌梗死后的心肌细胞凋亡和凋亡相关基因表达的变化

目的： 观察大鼠急性心肌梗死（AMI）后的心肌细胞凋亡和caspase-3、Bcl-2和Bax表达的变化。 方法: 105只雌性SD大鼠，随机取78只结扎左冠状动脉建立AMI模型，24 h存活43只作为心肌梗死组（MI组）；另27只设为假手术组（S组）；两组再按观察时点随机分为48 h和4周两亚组，即：MI 48 h（n=11）和MI 4周（n=13）组，S48 h（n=10）和S4周（n=10）组。末端脱氧核糖核苷酸转移酶介导的dUTP切口末端标记技术（TUNEL）和DNA凝胶电泳检测心肌细胞凋亡。免疫组化方法和Western blotting检测caspase-3、Bcl-2和Bax的表达。 结果： MI 48 h组动脉收缩压（SBP）、舒张压（DBP）、平均压（MAP）、左心室收缩压（LVSP）和左心室内压最大上升下降速率（±dp/dt）均显著低于S组（P<0.05, P<0.01），左心室舒张末压（LVEDP）显著高于S组（P<0.05）；MI 4周组除SBP、DBP和MAP无显著差异（均P>0.05）外，上述其它指标的变化与MI 48 h组相同，且LVEDP升高更为显著（P<0.01）；MI 48 h和4周两组梗死/疤痕区、梗死边缘区和非梗死区的心肌细胞凋亡指数均显著升高P<0.05,P<0.01），心肌细胞中“凋亡执行因子”caspase-3和“凋亡促进基因”Bax的表达亦均显著增高（P<0.05,P<0.01），而“凋亡抑制基因”Bcl-2仅在MI 48 h组梗死区心肌细胞中表达增加，“抑制凋亡复合基因”Bcl-2/Bax的比值仅在MI 48 h组降低。 结论： 大鼠AMI后，梗死区及其边缘区和非梗死区均有心肌细胞凋亡发生，伴“凋亡执行因子”caspase-3和“凋亡促进基因”Bax的表达增加；AMI早期，“凋亡抑制基因”Bcl-2在梗死区表达增加，但“抑制凋亡复合基因”Bcl-2/Bax的比值下降。     

长期胰岛素治疗通过促进BNP表达延缓缺血性心力衰竭的发展及其机制

 目的：探讨心肌梗死后长期胰岛素治疗对心脏结构与功能的影响及机制。方法：对成年雄性SD大鼠行冠状动脉左前降支结扎手术,并随机分为4组（每组8~10只）：（1）生理盐水组：心梗后1 mL·kg-1·d-1,ih,4周;（2）胰岛素组：2 U·kg-1·d-1,ih,4周;（3）胰岛素+wortmannin（Wm, PI3K抑制剂）组：Wm 15 μg·kg-1·d-1,胰岛素给药前15 min,ip;（4）假手术组不结扎冠脉,作为对照。检测各组大鼠心脏结构及功能,测定心肌细胞PI3K及p38 MAPK表达量,测定血清脑钠尿肽（BNP）及心肌BNP mRNA表达量。结果：心梗后胰岛素长期强化治疗4周可减少心脏纵轴长度/心脏重量,但对心脏重量/体重和心肌细胞横截面积无显著影响,并增加心脏射血分数、左心室发展压和左室压微分（均P<0.05）;此外,胰岛素治疗4周可增加PI3K表达和Akt磷酸化,降低p38 MAPK磷酸化水平,同时提高血清BNP水平而不改变心肌细胞BNP mRNA表达量,但该作用不能被Wm阻断（均P<0.05）。结论：心梗后长期胰岛素强化治疗可通过非PI3K-Akt依赖通路上调BNP水平,减轻心脏病理性重构并改善心功能,延缓缺血性心力衰竭的发展。     

右侧颈交感干离断对大鼠心肌梗死后炎症反应的抑制作用及对HMGB1/TLR4/NF-κB通路的影响

目的:观察右侧颈交感干离断(TCST)对大鼠心肌梗死后炎症反应的抑制作用及高迁移率族蛋白B1(HMGB1)的表达和TLR4/NF-κB信号通路的影响。方法:结扎左冠状动脉前降支制备急性心肌梗死(acute myocardial infarction,AMI)模型,将造模成功的大鼠随机分为心肌梗死(MI)组和心肌梗死+右侧颈交感干离断(MI+TCST)组,MI+TCST组在左冠状动脉前降支结扎后立即离断右侧颈交感神经干。MI组和MI+TCST组分别按模型制备及干预后1、3、7、14和28 d分为5个亚组,另设假手术(sham)组,只穿线不结扎,每组8只。建模后4周,超声心动图检测大鼠心脏功能,然后处死大鼠,取心脏计算心脏肥厚指数,并取梗死周围心肌组织采用HE染色观察心肌病理形态改变。Real-time PCR法检测不同时点梗死边缘区HMGB1、肿瘤坏死因子α(TNF-α)和白细胞介素6(IL-6)的m RNA表达。Western blot分析MI后不同时点梗死边缘区HMGB1和TLR4蛋白的表达变化,并进一步分析右侧TCST对HMGB1和TLR4/NF-κB信号通路蛋白表达的影响。结果:与MI组比较,MI+TCST组左心室射血分数(LVEF)和左心室短轴缩短分数(LVFS)显著升高(P0.05),左心室舒张末期内径(LVEDd)、左心室收缩末期内径(LVESd)和心脏肥厚指数显著降低(P0.05),梗死边缘区各时点HMGB1、TNF-α和IL-6的m RNA表达水平显著降低(P0.05)。Western blot检测结果显示,与sham组比较,HMGB1蛋白的表达在MI后3 d开始升高,并于7 d达到高峰,之后逐渐下降,28 d时仍明显高于假手术组(P0.05);TLR4蛋白的表达变化与HMGB1一致。进一步研究发现右侧TCST可显著降低心肌组织HMGB1和TLR4/NF-κB信号通路蛋白的表达(P0.05)。结论:右侧颈交感干离断可改善MI后心室重构,发挥保护心功能的作用,其机制可能与其抑制HMGB1/TLR4/NF-κB信号通路,减轻炎症反应有关。     

Angiotensin II-induced dilated cardiomyopathy in Balb/c but not C57BL/6J mice

Balb/c mice, which are T-helper lymphocyte 2 (Th2) responders, are highly susceptible to infectious and non-infectious heart diseases, whereas C57BL/6 mice (Th1 responders) are not. Angiotensin II (Ang II) is not only a vasopressor but also a pro-inflammatory factor that leads to cardiac hypertrophy, fibrosis and dysfunction. We hypothesized that Ang II exacerbates cardiac damage in Balb/c but not in C57BL/6 mice even though both strains have a similar level of hypertension. Twelve-week-old male C57BL/6J and Balb/c mice received either vehicle or Ang II (1.4 mg kg(-1) day(-1), s.c. via osmotic minipump) for 8 weeks. At baseline, Balb/c mice exhibited the following: (1) a lower heart rate; (2) an enlarged left ventricular chamber; (3) a lower ejection fraction and shortening fraction; and (4) twice the left ventricular collagen deposition of age-matched C57BL/6J mice. Angiotensin II raised systolic blood pressure (to ～150 mmHg) and induced cardiomyocyte hypertrophy in a similar manner in both strains. While C57BL/6J mice developed compensatory concentric hypertrophy and fibrosis in response to Ang II, Balb/c mice demonstrated severe left ventricular chamber dilatation, wall thinning and fibrosis, leading to congestive heart failure as evidenced by dramatically decreased ejection fraction and lung congestion (significant increase in lung weight), which are both characteristic of dilated cardiomyopathy. Our study suggests that the Th phenotype plays an active role in cardiac remodelling and function both in basal conditions and in hypertension. Angiotensin II-induced dilated cardiomyopathy in Balb/c mice is an ideal animal model for studying the impact of the adaptive immune system on cardiac remodelling and function and for testing strategies to prevent or treat hypertension-associated heart failure.     

葛瑞林对心肌梗死致心力衰竭大鼠保护作用及生长分化因子-15的影响

目的 制作葛瑞林（Ghrelin）早期干预心肌梗死致心力衰竭(HF)大鼠模型,探讨生长分化因子-15(GDF-15)表达水平与HF程度相关性,为HF临床治疗奠定理论学基础。方法 80只Wistar大鼠于造模成活6h后被随机分为假手术（A）组（n =18)、HF模型(B)组（n =27)和HF模型干预(C)组（n =27),通过酶联免疫吸附（ELISA）及实时定量 PCR,于造模后3d、1周、2周、4周、8周分别检测各组血中GDF-15表达变化及2周、4周、8周末3组HF大鼠心肌组织中GDF-15 mRNA表达水平的改变;电镜下观察各组大鼠心肌组织超微结构,并均于处死前行B型超声检测心功能。结果 B组大鼠血GDF-15及心肌组织GDF-15 mRNA表达水平明显高于C组,低于A组,差异具有统计学意义（P ＜0.001）;8周末超声检测结果显示,B组大鼠较A、C两组大鼠心脏增大明显,左室舒张及收缩末期内径均明显增加,差异具有统计学意义（P ＜0.001）;B组大鼠左室舒张末期室间隔厚度、左室后壁厚度及射血分数值均较A、C两组大鼠显著降低,差异具有统计学意义（P ＜0.001）;此外,心肌超微结构显示C组较B组改变明显。结论 Ghrelin早期干预HF大鼠能改善心功能,降低死亡率;GDF-15表达水平能反映HF病变程度,并可作为辅助检测HF新的标记物。