我们感谢的Helio公司萨尔加多博士，雷纳塔Lataro和毛罗奥利维拉，医学院的里贝朗普雷图，巴西圣保罗大学和马斯特里赫特大学，心血管研究所马斯特里赫特，本詹森博士，在设置过程中的慷慨援助。 这项工作是支持的FONDECYT授出N°11090114 SDC

协议的Facultad的MEDICINA CLINICA ALEMANA省大学与发展的伦理委员会批准。 一，准备多巴酚丁胺输注<ol><li>将10毫克多巴酚丁胺溶解在20毫升无菌馏分水，为了获得500微克/毫升多巴酚丁胺的储备液。分装并储存于-20°C。这种解决方案可以使用至少3个月。 </li><li>解冻多巴酚丁胺储备溶液的等分试样，在室温下。 </li><li>稀释多巴酚丁胺原液在无菌的0.9％NaCl溶液中，以获得的多巴酚丁胺工作溶液，该浓度是使用下面的公式计算的:的多巴酚丁胺（微克/毫升）=体重×0.2。 </li><li>填写1毫升注射器29Gx1 / 2"多巴酚丁胺工作方案。 </li><li>注射器的针插入到一个20厘米的PE-10管。 </li><li>在输液泵，按照制造商的指示调整注射器。 </li><li>设置了坡道输液，在一步步格式，同比增长10μl/ min的每一步，为6个步骤。 </li></ol> II。准备压力传感器<ol><li>为了尽量减少信号漂移，淹没压力传感器在无菌水中，在37℃下至少15分钟。不要浸泡导管超过0.5厘米深，以防止，静水压力影响的压力传感器。 </li><li>电校准的压力传感器，在25和100毫米汞柱。电输入（伏）被转换为压力信号（毫米汞柱）。 </li><li>设置的2 k / s的采样率，并使用与切断在100赫兹的低通滤波器。设置零毫米汞柱的压力信号。 </li><li>标记导管尖端的15毫米。遥远的引入点到达心脏，估计超声心动图检查，发现存在的导管插入左心室。 </li></ol> III。鼠标导管插入术的准备<ol><li>重量C57BL / 6雄性小鼠，30〜32周龄。 </li><li>注入腹腔注射60微克/公斤氯胺酮和4μg/公斤甲苯噻嗪1。注:其他麻醉药可能被用于，例如:350 - 450微克/千克阿佛丁，50微克/公斤的戊巴比妥钠或1.5 - 2％异氟烷2-3。 </li><li>用电动剃须刀刮颈部。 </li><li>将麻醉鼠标在加热恒温加热板在仰卧位。它的四肢固定，用胶带纸。 </li><li>执行一个脚趾头掐确认完整的镇静作用。 </li><li>轻轻插入直肠探头体温监测。建议使用vaselinized探头。 </li><li>如果体温不同，从37°C±0.5°C，通过调整加热板。 </li><li>将鼠标的鼻子附近的氧气供应。 </li><li>在体视显微镜下，将鼠标颈部。 </li></ol> IV。数据采集<ol><li>在LabChartPro 7软件，选择压力注册一个通道，一个通道的心脏率（HR）注册。对于后者，选择"选项"循环测量"，并设置测量率。 </li><li>对于压力通道设置量程范围:0〜150毫米汞柱。 </li><li>对于HR通道设置量程范围:200〜600 BPM。 </li><li>按开始键开始登记。 </li><li>插入注释，说明程序进行，例如:麻醉管理，开始输注多巴酚丁胺，多巴胺的浓度，呼吸的变化。 </li></ol>五，心导管检查4,5 <ol><li>执行右侧的下巴附近的一个小切口。用剪刀分离的皮肤，肌肉结缔组织。 </li><li>执行的气管上的右侧的纵向解剖（1.5 - 2厘米）的。分离的结缔组织，脂肪和肌肉弯曲的镊子，以暴露右侧颈总动脉，气管附近。 </li><li>将右侧的动物暴露颈动脉中的膨胀。脉动由心脏产生的压力有利于识别的动脉。颈内静脉，是暗红色的，是在右边。 </li><li>从相邻的组织中弯钳分离动脉。迷走神经，它类似于一个白线，沿动脉。 </li><li>切6/0丝线和"双"，一块20厘米。 </li><li>通过"双"线下动脉由左到右。剪断线，以获得独立的目的。 </li><li>通过第三个线程（10厘米）以下的动脉。 </li><li>打一个紧结线位置附近的头部，并在更远端的一个松散的线程。 </li><li>配合在中间的线程中的一个松散的结，并修复中间线程具有纸带的加热垫的右端。 </li><li>保持湿润​​滴无菌的0.9％NaCl溶液中的颈动脉。用棉签擦干多余的液体。 </li><li>拉伸用止血钳底线。 </li><li>修复止血钳剪刀的位置，用p缓慢的腹部皮肤，拉伸面线，以阻塞血液流动。验证周围的结缔组织的血管已被删除。应该是满血的动脉和被剥夺的脉冲。防止线程产生的扭转力对动脉。 </li><li>品牌的截面缺口的底部附近的动脉与Vannas微剪刀。将血滴洒。 </li><li>颈内动脉，将导管插入。一定要介绍整个压力传感器。请确认有没有血损失。 </li><li>轻轻地调整中​​间线结，以保持导管的位置。不要压缩太多，压力传感器是非常脆弱的。 </li><li>松开止血钳剪刀从动物的腹部。 </li><li>与手握住导管推中间的线程，以避免血液流失。注:动脉全是血。 </li><li>开始记录压力信号。 </li><li>当导管在里面，动脉压力信号从60-70到100-120毫米汞柱波动。压力信号的形状显示在图1.A.注意:如果你有兴趣，在这个时间点，您可以记录动脉血压，如果信号是稳定的，至少5分钟。 HR值，得到从压力波形考虑的时间间隔为30秒的记录信号。这是可能的直接测量的HR也使用的ECG方法，根据与调查目标。 </li><li>轻轻推导管观察的压力信号（ 图1B）中的变化的形状。一旦导管的左心室内的压力信号的波动从0到100〜120毫米汞柱。如果它是难以滑动的导管，用两个手指捏住动物胸部。 </li><li>连续控制呼吸率，体温，麻醉水平和压力信号。所有这些应保持稳定。 </li></ol> VI。多巴酚丁胺输液<ol><li&gt;对于颈静脉插管确保向后剥离静脉周围的脂肪组织，以防止它的穿孔。静脉阻塞的外科手术是颈动脉所示的过程类似。 </li><li>介绍一个PE-10管进入静脉。确认没有被阻塞，血液流动的落后注射器的柱塞移动。 </li><li>多巴酚丁胺输液开始用10微升/分钟，并完成与60μl/ min的。在每一个步骤中，输注速率维持2分钟6。 </li><li>最后多巴酚丁胺剂量后，与过量的麻醉动物安乐死。 </li></ol> VII。数据分析<ol><li>对于数据分析，选择你感兴趣的部分记录的数据。压力信号是稳定的，一定要考虑的时间间隔。 </li><li>选择"设置"图标，在血压模块。指示所选择的类型的压力信号。 </li><li>自动的LabChartPro的7个软件显示的意思是，最大值和最低值的人力资源，收缩压（P 最大值 ），舒张压（P 分钟 ），舒张末压（EDP），最大正压发展（DP / dt（下标max））和最大负压发展（DP / DT 分钟的 ）。此外，心脏参数可以描述上的压迹。 </li></ol>

<ol>
	<li>Hart, C. Y., Burnett, J. C., Redfield, M. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+avertin+versus+xylazine-ketamine+anesthesia+on+cardiac+function+in+normal+mice.">Effects of avertin versus xylazine-ketamine anesthesia on cardiac function in normal mice.</a> Am. J. Physiol. Heart Circ. Physiol. 281, H1938-H1945 (2001).</li><li>Janssen, B. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+anesthetics+on+systemic+hemodynamics+in+mice.">Effects of anesthetics on systemic hemodynamics in mice.</a> Am. J. Physiol. Heart Circ. Physiol. 287, H1618-H1624 (2004).</li><li>Lorenz, J. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+practical+guide+to+evaluating+cardiovascular,+renal,+and+pulmonary+function+in+mice.">A practical guide to evaluating cardiovascular, renal, and pulmonary function in mice.</a> Am. J. Physiol. Regul. Integr. Comp. Physiol. 282, R1565-R1582 (2002).</li><li>Lorenz, J. N., Robbins, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measurement+of+intraventricular+pressure+and+cardiac+performance+in+the+intact+closed-chest+anesthetized+mouse.">Measurement of intraventricular pressure and cardiac performance in the intact closed-chest anesthetized mouse.</a> Am. J. Physiol. 272, H1137-H1146 (1997).</li><li>Nemoto, S., DeFreitas, G., Carabello, B. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cardiac+catheterization+technique+in+a+closed-chest+murine+model.">Cardiac catheterization technique in a closed-chest murine model.</a> Contemp. Top. Lab Anim. Sci. 42, 34-38 (2003).</li><li>Daniels, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Impaired+cardiac+functional+reserve+in+type+2+diabetic+db/db+mice+is+associated+with+metabolic,+but+not+structural,+remodelling.">Impaired cardiac functional reserve in type 2 diabetic db/db mice is associated with metabolic, but not structural, remodelling.</a> Acta Physiol. (Oxf). 200, 11-22 (2010).</li><li>De Celle, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Long-term+structural+and+functional+consequences+of+cardiac+ischaemia-reperfusion+injury+in+vivo+in+mice.">Long-term structural and functional consequences of cardiac ischaemia-reperfusion injury in vivo in mice.</a> Exp. Physiol. 89, 605-615 (2004).</li><li>Huntgeburth, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transforming+growth+factor+beta+oppositely+regulates+the+hypertrophic+and+contractile+response+to+beta-adrenergic+stimulation+in+the+heart.">Transforming growth factor beta oppositely regulates the hypertrophic and contractile response to beta-adrenergic stimulation in the heart.</a> PLoS One. 6, e26628 (2011).</li><li>Reddy, A. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cardiac+function+in+young+and+old+Little+mice.">Cardiac function in young and old Little mice.</a> J. Gerontol. A. Biol. Sci. Med. Sci. 62, 1319-1325 (2007).</li><li>Christoffersen, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cardiac+lipid+accumulation+associated+with+diastolic+dysfunction+in+obese+mice.">Cardiac lipid accumulation associated with diastolic dysfunction in obese mice.</a> Endocrinology. 144, 3483-3490 (2003).</li></ol>

没有利益冲突的声明。

多巴酚丁胺诱导的心脏压力测试通过心导管检查和监控是艰苦的。尽管如此，这里的协议描述的训练用短的时间内，在一个实验中，最后约一小时，它是可能的，以评估六个血流动力学参数。 这里提出的协议的关键步骤是血管插管。关于颈动脉插管，执行切口应足够深，以打破三个组织层的动脉，和足够大，以允许通过的导管。关于颈静脉插管，而出血的危险性是低的，静?...

<table border="1"><tbody><tr><td></td><td></td><td></td><td> 试剂 </td></tr><tr><td> PE-50/10 </td><td>华纳仪器</td><td> 64-0752 </td><td></td></tr><tr><td>丝线6/0 HR17 </td><td>塔古姆</td><td> SN0713K </td><td></td></tr><tr><td> xylacin 20毫克/毫升</td><td>化验所Centrovet </td><td></td><td></td></tr><tr><td>氯胺酮100毫克/毫升</td><td>拖动制药</td><td></td><td></td></tr><tr><td> 0.9％氯化钠</td><td>实验室桑德森SA </td><td></td><td></td></tr><tr><td>盐酸多巴酚丁胺</td><td> Sigma-Aldrich公司</td><td> D0676 </td><td></td></tr><tr><td>注射器U-100胰岛素29G所述½" </td><td>泰尔茂医疗器械有限公司</td><td></td><td></td></tr><tr><td>钳解剖微型11.5厘米风格7 </td><td>劳顿MEDIZINTECHNIK </td><td> 09-0959 </td><td></td></tr><tr><td>格雷夫钳CVD0.7毫米7厘米</td><td>劳顿M​​edizintechnik的</td><td> 62-0263 </td><td></td></tr><tr><td>夹Dieffenbach斗牛犬氯STR 38毫米</td><td>劳顿M​​edizintechnik的</td><td> 60-010 </td><td></td></tr><tr><td> Vannas剪刀8厘米STR FH </td><td>劳顿M​​edizintechnik的</td><td> 63-1400 </td><td></td></tr><tr><td></td><td></td><td></td><td> 设备 </td></tr><tr><td> SPR-671 MIKRO笔尖压力导管</td><td>米勒仪器</td><td> 840-6719 </td><td></td></tr><tr><td>压力控制单元PCU-2000 </td><td>米勒仪器</td><td> 880-0129 </td><td></td></tr><tr><td> PowerLab系统4/30 </td><td>的ADInstruments Pty有限公司</td><td> ML866 </td><td></td></tr><tr><td> LabChartPro 7 </td><td>的ADInstruments Pty有限公司</td><td> MLU260 / 7 </td><td></td></tr><tr><td> Legato200输液泵</td><td> KdScientific </td><td> KD-KDS210P </td><td></td></tr><tr><td> TCAT-2LV温控器，恒温加热板</td><td> PhysiTemp仪器公司</td><td></td><td></td></tr><tr><td>医用氧气供应</td><td> Indura </td><td></td><td></td></tr><tr><td>直肠探头</td><td>的ADInstruments Pty有限公司</td><td> MLT1404 </td><td></td></tr><tr><td>三目显微镜，同轴照明</td><td> LW科学</td><td> Z2B-TRI-ETNE，ILP-1502-LTS1，ILP-1502-DGGF </td><td></td></tr></tbody></table>

cardiac stress test induced by dobutamine and monitored by cardiac catheterization in mice

多巴酚丁胺是更高的亲和在心脏（β1）比在动脉（β2）受体表达的受体表达的β-肾上腺素能受体激动剂。当全身给药时，它增加心脏的需求。因此中，多巴酚丁胺不能控制异常的节奏潜在风险的梗死或缺血区。 无论是ecocardiography或心导管检查，心脏负荷试验过程中可以进行监测心脏功能。后者是一种侵入性，但更精确和信息，前者的技术。 多巴酚丁胺诱导的心脏压力测试和监控完成这里所描述的心导管检查允许的话，在一个单一的实验，测量血流动力学参数如下:心脏心率（HR），收缩压，舒张压，舒张末压，最大正压力（DP / dt（下标max））和最大的负面新闻:URE发展（dP / dt的分钟 ），在基准条件下增加剂量多巴酚丁胺。 正如预期的那样，在正常小鼠中，我们观察到的多巴酚丁胺的剂量相关的增加，HR，dp / dt 最大值和dP / dt 分钟 。此外，在最高剂量测试（12毫微克/克/分钟），高脂肪的饮食诱导的肥胖小鼠的心功能失代偿被揭穿。

动脉压信号被定义的收缩压和舒张压。当该压力传感器是左心室内，其压力（LVP）波形的特征在于由下降到零的舒张压和心室收缩（ 图1）的左心房收缩前的外观。在基准条件下，氯胺酮-甲苯噻嗪麻醉的正常小鼠HR为280±24，P 最大为107±8，P 5 分钟 ±1，EDP 14±2，dP / dt的最大值为6081±365和dP / dt 分钟 5230±526。 在图2中可?...

Watch this Scientific Journal Video about Cardiac Stress Test Induced by Dobutamine and Monitored by Cardiac Catheterization in Mice at JoVE.com

Cardiac Stress Test Induced by Dobutamine and Monitored by Cardiac Catheterization in Mice

我们描述的协议来执行的心脏压力测试在正常小鼠的心脏导管插入术多巴酚丁胺诱导和监控。此外，我们揭露其应用到亚临床心脏疾病，高脂饮食诱导的肥胖小鼠。

多巴酚丁胺诱导的心脏压力测试和监控通过在小鼠心脏导管插入术

Dobutamine is a &beta;-adrenergic agonist with an affinity higher for receptor expressed in the heart (&beta;1) than for receptors expressed in the ...

cardiac-stress-test-induced-dobutamine-monitored-cardiac

Research

JoVE Journal

Medicine

17.9K 次观看.  Clínica Alemana Universidad del Desarrollo. 我们描述的协议来执行的心脏压力测试在正常小鼠的心脏导管插入术多巴酚丁胺诱导和监控。此外，我们揭露其应用到亚临床心脏疾病，高脂饮食诱导的肥胖小鼠。

视频: Cardiac Stress Test Induced by Dobutamine and Monitored by Cardiac Catheterization in Mice

Assessment of Right Ventricular Structure and Function in Mouse Model of Pulmonary Artery Constriction by Transthoracic Echocardiography

Emerging clinical data support the notion that RV dysfunction is critical to the pathogenesis of cardiovascular disease and heart failure1-3. Moreover, the RV is significantly affected in pulmonary diseases such as pulmonary artery hypertension (PAH). In addition, the RV is remarkably sensitive to cardiac pathologies, including left ventricular (LV) dysfunction, valvular disease or RV infarction4. To understand the role of RV in the pathogenesis of cardiac diseases, a reliable and noninvasive method to access the RV structurally and functionally is essential.
A noninvasive trans-thoracic echocardiography (TTE) based methodology was established and validated for monitoring dynamic changes in RV structure and function in adult mice. To impose RV stress, we employed a surgical model of pulmonary artery constriction (PAC) and measured the RV response over a 7-day period using a high-frequency ultrasound microimaging system. Sham operated mice were used as controls. Images were acquired in lightly anesthetized mice at baseline (before surgery), day 0 (immediately post-surgery), day 3, and day 7 (post-surgery). Data was analyzed offline using software.
Several acoustic windows (B, M, and Color Doppler modes), which can be consistently obtained in mice, allowed for reliable and reproducible measurement of RV structure (including RV wall thickness, end-diastolic&#160;and end-systolic dimensions), and function (fractional area change, fractional shortening, PA peak velocity, and peak pressure gradient) in normal mice and following PAC.
Using this method, the pressure-gradient resulting from PAC was accurately measured in real-time using Color Doppler mode and was comparable to direct pressure measurements performed with a Millar high-fidelity microtip catheter. Taken together, these data demonstrate that RV measurements obtained from various complimentary views using echocardiography are reliable, reproducible and can provide insights regarding RV structure and function. This method will enable a better understanding of the role of RV cardiac dysfunction.

Right ventricle (RV) dysfunction is critical to the pathogenesis of cardiovascular disease, yet limited methodologies are available for its evaluation. Recent advances in ultrasound imaging provide a noninvasive and accurate option for longitudinal RV study. Herein, we detail a step-by-step echocardiographic method using a murine model of RV pressure overload.

右心室结构和功能的肺动脉缩窄经胸超声小鼠模型的评估

Emerging clinical data support the notion that RV dysfunction is critical to the pathogenesis of cardiovascular disease and heart failure1-3. Moreover, ...

科研

医学

A Method to Study the Impact of Chemically-induced Ovarian Failure on Exercise Capacity and Cardiac Adaptation in Mice

The risk of cardiovascular disease (CVD) increases in post-menopausal women, yet, the role of exercise, as a preventative measure for CVD risk in post-menopausal women has not been adequately studied. Accordingly, we investigated the impact of voluntary cage-wheel exercise and forced treadmill exercise on cardiac adaptation in menopausal mice. The most commonly used inducible model for mimicking menopause in women is the ovariectomized (OVX) rodent. However, the OVX model has a few dissimilarities from menopause in humans. In this study, we administered 4-vinylcyclohexene diepoxide (VCD) to female mice, which accelerates ovarian failure as an alternative menopause model to study the impact of exercise in menopausal mice. VCD selectively accelerates the loss of primary and primordial follicles resulting in an endocrine state that closely mimics the natural progression from pre- to peri- to post-menopause in humans. To determine the impact of exercise on exercise capacity and cardiac adaptation in VCD-treated female mice, two methods were used. First, we exposed a group of VCD-treated and untreated mice to a voluntary cage wheel. Second, we used forced treadmill exercise to determine exercise capacity in a separate group VCD-treated and untreated mice measured as a tolerance to exercise intensity and endurance.

Two exercise paradigms were tested on a newly developed chemically induced menopausal mouse model to examine the impact of menopause on exercise capacity and cardiac adaption to exercise.

一个方法研究的化学诱导卵巢早衰的运动能力和适应心脏的影响在小鼠

The risk of cardiovascular disease (CVD) increases in post-menopausal women, yet, the role of exercise, as a preventative measure for CVD risk in ...

Early Detection of Drug-Induced Renal Hemodynamic Dysfunction Using Sonographic Technology in Rats

The kidney normally functions to maintain hemodynamic homeostasis and is a major site of damage caused by drug toxicity. Drug-induced nephrotoxicity is estimated to contribute to 19- 25% of all clinical cases of acute kidney injury (AKI) in critically ill patients. AKI detection has historically relied on metrics such as serum creatinine (sCr) or blood urea nitrogen (BUN) which are demonstrably inadequate in full assessment of nephrotoxicity in the early phase of renal dysfunction. Currently, there is no robust diagnostic method to accurately detect hemodynamic alteration in the early phase of AKI while such alterations might actually precede the rise in serum biomarker levels. Such early detection can help clinicians make an accurate diagnosis and help in in decision making for therapeutic strategy. Rats were treated with Cisplatin to induce AKI. Nephrotoxicity was assessed for six days using high-frequency sonography, sCr measurement and upon histopathology of kidney. Hemodynamic evaluation using 2D and Color-Doppler images were used to serially study nephrotoxicity in rats, using the sonography. Our data showed successful drug-induced kidney injury in adult rats by histological examination. Color-Doppler based sonographic assessment of AKI indicated that resistive-index (RI) and pulsatile-index (PI) were increased in the treatment group; and peak-systolic velocity (mm/s), end-diastolic velocity (mm/s) and velocity-time integral (VTI, mm) were decreased in renal arteries in the same group. Importantly, these hemodynamic changes evaluated by sonography preceded the rise of sCr levels. Sonography-based indices such as RI or PI can thus be useful predictive markers of declining renal function in rodents. From our sonography-based observations in the kidneys of rats that underwent AKI, we showed that these noninvasive hemodynamic measurements may consider as an accurate, sensitive and robust method in detecting early stage kidney dysfunction. This study also underscores the importance of ethical issues associated with animal use in research.

Early stage hemodynamic dysfunction is critical to the development of kidney disease. Yet, detection methodologies are limited. Recent advances in sonography provide a noninvasive, accurate option for early detection of kidney injury. This study outlines a step-by-step, sonographic methodology for detecting kidney dysfunction using a drug-induced nephrotoxicity rat model.

大鼠使用超声技术药物引起的肾血流动力学障碍的早期检测

The kidney normally functions to maintain hemodynamic homeostasis and is a major site of damage caused by drug toxicity. Drug-induced nephrotoxicity is ...

Cardiac Catheterization in Mice to Measure the Pressure Volume Relationship: Investigating the Bowditch Effect

Animal models that mimic human cardiac disorders have been created to test potential therapeutic strategies. A key component to evaluating these strategies is to examine their effects on heart function. There are several techniques to measure in vivo cardiac mechanics (e.g., echocardiography, pressure/volume relations, etc.). Compared to echocardiography, real-time left ventricular (LV) pressure/volume analysis via catheterization is more precise and insightful in assessing LV function. Additionally, LV pressure/volume analysis provides the ability to instantaneously record changes during manipulations of contractility (e.g., &#946;-adrenergic stimulation) and pathological insults (e.g., ischemia/reperfusion injury). In addition to the maximum (+dP/dt) and minimum (-dP/dt) rate of pressure change in the LV, an accurate assessment of LV function via several load-independent indexes (e.g., end systolic pressure volume relationship and preload recruitable stroke work) can be attained. Heart rate has a significant effect on LV contractility such that an increase in the heart rate is the primary mechanism to increase cardiac output (i.e., Bowditch effect). Thus, when comparing hemodynamics between experimental groups, it is necessary to have similar heart rates. Furthermore, a hallmark of many cardiomyopathy models is a decrease in contractile reserve (i.e., decreased Bowditch effect). Consequently, vital information can be obtained by determining the effects of increasing heart rate on contractility. Our and others data has demonstrated that the neuronal nitric oxide synthase (NOS1) knockout mouse has decreased contractility. Here we describe the procedure of measuring LV pressure/volume with increasing heart rates using the NOS1 knockout mouse model.

This article describes the measurement of murine left ventricular function via pressure/volume analysis at different heart rates.

心导​​管在小鼠测量压力体积的关系:调查的影响鲍迪奇

Animal models that mimic human cardiac disorders have been created to test potential therapeutic strategies. A key component to evaluating these ...

Myocardial Infarction in Neonatal Mice, A Model of Cardiac Regeneration

Myocardial infarction induced by coronary artery ligation has been used in many animal models as a tool to study the mechanisms of cardiac repair and regeneration, and to define new targets for therapeutics. For decades, models of complete heart regeneration existed in amphibians and fish, but a mammalian counterpart was not available. The recent discovery of a postnatal window during which mice possess regenerative capabilities has led to the establishment of a mammalian model of cardiac regeneration. A surgical model of mammalian cardiac regeneration in the neonatal mouse is presented herein. Briefly, postnatal day 1 (P1) mice are anesthetized by isoflurane and placed on an ice pad to induce hypothermia. After the chest is opened, and the left anterior descending coronary artery (LAD) is visualized, a suture is placed around the LAD to inflict myocardial ischemia in the left ventricle. The surgical procedure takes 10-15 min. Visualizing the coronary artery is crucial for accurate suture placement and reproducibility. Myocardial infarction and cardiac dysfunction are confirmed by triphenyl-tetrazolium chloride (TTC) staining and echocardiography, respectively. Complete regeneration 21 days post myocardial infarction is verified by histology. This protocol can be used to as a tool to elucidate mechanisms of mammalian cardiac regeneration after myocardial infarction.

This protocol describes a highly reproducible model of cardiac regeneration by surgical induction of myocardial infarction in the left ventricle of postnatal day 1 mice. The method involves induction of hypothermic anesthesia and ligation of the left anterior descending coronary artery.

心肌梗死新生小鼠，心肌再生的模型

Myocardial infarction induced by coronary artery ligation has been used in many animal models as a tool to study the mechanisms of cardiac repair and ...

A Model of Glaucoma Induced by Circumlimbal Suture in Rats and Mice

The circumlimbal suture is a technique for inducing experimental glaucoma in rodents by chronically elevating intraocular pressure (IOP), a well-known risk factor for glaucoma. This protocol demonstrates a step-by-step guide on this technique in Long Evans rats and C57BL/6 mice. Under general anesthesia, a "purse-string" suture is applied on the conjunctiva, around the equator and behind the limbus of the eye. The fellow eye serves as an untreated control. Over the duration of our study, which was a period of 8 weeks for rats and 12 weeks for mice, IOP remained elevated, as measured regularly by rebound tonometry in conscious animals without topical anesthesia. In both species, the sutured eyes showed electroretinogram features consistent with preferential inner retinal dysfunction. Optical coherence tomography showed selective thinning of the retinal nerve fiber layer. Histology of the rat retina in cross-section found reduced cell density in the ganglion cell layer, but no change in other cellular layers. Staining of flat-mounted mouse retinae with a ganglion cell specific marker (RBPMS) confirmed ganglion cell loss. The circumlimbal suture is a simple, minimally invasive and cost-effective way to induce ocular hypertension that leads to ganglion cell injury in both rats and mice.

Chronic ocular hypertension is induced by applying a circumlimbal suture in rats and mice, leading to functional and structural deterioration of the retinal ganglion cells consistent with glaucoma.

Circumlimbal 缝合法诱导大鼠和小鼠青光眼模型的建立

The circumlimbal suture is a technique for inducing experimental glaucoma in rodents by chronically elevating intraocular pressure (IOP), a well-known ...

Isolation of Atrial Myocytes from Adult Mice

The electrophysiological properties of atrial myocytes importantly affect overall cardiac function. Alterations in the underlying ionic currents responsible for the action potential can cause pro-arrhythmic substrates that underlie arrhythmias, such as atrial fibrillation, which are highly prevalent in many conditions and disease states. Isolating adult mouse atrial cardiomyocytes for use in patch-clamp experiments has greatly advanced our knowledge and understanding of the cellular electrophysiology in the healthy atrial myocardium and in the setting of atrial pathophysiology. In addition, studies using genetic mouse models have elucidated the role of a vast array of proteins in regulating atrial electrophysiology. Here we provide a detailed protocol for the isolation of cardiomyocytes from the atrial appendages of adult mice using a combination of enzymatic digestion and mechanical dissociation of these tissues. This approach consistently and reliably yields isolated atrial cardiomyocytes that can then be used to characterize cellular electrophysiology by measuring action potentials and ionic currents in patch-clamp experiments under a number of experimental conditions.

This protocol is used to isolate single atrial cardiomyocytes from the adult mouse heart using a chunk digestion approach. This approach is used to isolate right or left atrial myocytes that can be used to characterize atrial myocyte electrophysiology in patch-clamp studies.

从成年小鼠分离心膜肌细胞

The electrophysiological properties of atrial myocytes importantly affect overall cardiac function. Alterations in the underlying ionic currents ...

Biventricular Assessment of Cardiac Function and Pressure-Volume Loops by Closed-Chest Catheterization in Mice

Assessment of cardiac function is essential to conduct cardiovascular and pulmonary-vascular preclinical research. Pressure-volume loops (PV loops) generated by recording both pressure and volume during cardiac catheterization are vital when assessing both systolic and diastolic cardiac function. Left and right heart function are closely related, reflected in ventricular interdependence. Thus, recording biventricular function in the same animal is important to get a complete assessment of cardiac function. In this protocol, a closed chest approach to cardiac catheterization consistent with the way catheterization is performed in patients is adopted in mice. While challenging, the closed chest strategy is a more physiological approach, because opening the chest results in major changes in preload and afterload that create artifacts, most notably a fall in systemic blood pressure. While high-resolution echocardiography is used to assess rodents, cardiac catheterization is invaluable, particularly when assessing diastolic pressures in both ventricles.
Described here is a procedure to perform invasive, closed chest, sequential left and right ventricular pressure-volume (PV) loops in the same animal. PV loops are acquired using&#160;admittance technology with a mouse pressure-volume catheter and pressure-volume system acquisition. The procedure is described, beginning with the neck dissection, which is required to access the right jugular vein and the right carotid artery, to the insertion and positioning of the catheter, and finally the data acquisition. Then, the criteria required to ensure the acquisition of high-quality PV loops are discussed. Finally, the analysis of the left and right ventricular PV loops and the different hemodynamic parameters available to quantify systolic and diastolic ventricular function are briefly described.

Presented here is a protocol to assess biventricular heart function in mice by generating pressure-volume (PV) loops from the right and left ventricle in the same animal using closed chest catheterization. The focus is on the technical aspect of surgery and data acquisition.

小鼠闭胸导管插入术对心功能和压力-容积环的双心室评估

Assessment of cardiac function is essential to conduct cardiovascular and pulmonary-vascular preclinical research. Pressure-volume loops (PV loops) ...

A Large Animal Model for Acute Kidney Injury by Temporary Bilateral Renal Artery Occlusion

Acute kidney injury (AKI) is associated with higher risk for morbidity and mortality post-operatively. Ischemia-reperfusion injury (IRI) is the most common cause of AKI. To mimic this clinical scenario, this study presents a highly reproducible large animal model of renal IRI in swine using temporary percutaneous bilateral balloon-catheter occlusion of the renal arteries. The renal arteries are occluded for 60 min by introducing the balloon-catheters through the femoral and carotid artery and advancing them into the proximal portion of the arteries. Iodinated contrast is injected in the aorta to assess any opacification of the kidney vessels and confirm the success of the artery occlusion. This is furtherly confirmed by the flattening of the pulse waveform at the tip of the balloon catheters. The balloons are deflated and removed after 60 min of bilateral renal artery occlusion, and the animals are allowed to recover for 24 h. At the end of the study, plasma creatinine and blood urea nitrogen significantly increase, while eGFR and urine output significantly decrease. The need for iodinated contrast is minimal and does not affect renal function. Bilateral renal artery occlusion better mimics the clinical scenario of perioperative renal hypoperfusion, and the percutaneous approach minimizes the impact of the inflammatory response and the risk of infection seen with an open approach, such as a laparotomy. The ability to create and reproduce this clinically relevant swine model eases the clinical translation to humans.

This study presents a highly reproducible large animal model of renal ischemia-reperfusion injury in swine using temporary percutaneous bilateral balloon-catheter occlusion of the renal arteries for 60 min and reperfusion for 24 h.

临时双性肾动脉闭塞的急性肾损伤大型动物模型

Acute kidney injury (AKI) is associated with higher risk for morbidity and mortality post-operatively. Ischemia-reperfusion injury (IRI) is the most ...

Advanced Cardiac Rhythm Management by Applying Optogenetic Multi-Site Photostimulation in Murine Hearts

Ventricular tachyarrhythmias are a major cause of mortality and morbidity worldwide. Electrical defibrillation using high-energy electric shocks is currently the only treatment for life-threatening ventricular fibrillation. However, defibrillation may have side-effects, including intolerable pain, tissue damage, and worsening of prognosis, indicating a significant medical need for the development of more gentle cardiac rhythm management strategies. Besides energy-reducing electrical approaches, cardiac optogenetics was introduced as a powerful tool to influence cardiac activity using light-sensitive membrane ion channels and light pulses. In the present study, a robust and valid method for successful photostimulation of Langendorff perfused intact murine hearts will be described based on multi-site pacing applying a 3 x 3 array of micro light-emitting diodes (micro-LED). Simultaneous optical mapping of epicardial membrane voltage waves allows the investigation of the effects of region-specific stimulation and evaluates the newly induced cardiac activity directly on-site. The obtained results show that the efficacy of defibrillation is strongly dependent on the parameters chosen for photostimulation during a cardiac arrhythmia. It will be demonstrated that the illuminated area of the heart plays a crucial role for termination success as well as how the targeted control of cardiac activity during illumination for modifying arrhythmia patterns can be achieved. In summary, this technique provides a possibility to optimize the on-site mechanism manipulation on the way to real-time feedback control of cardiac rhythm and, regarding the region specificity, new approaches in reducing the potential harm to the cardiac system compared to the usage of non-specific electrical shock applications.

This work reports a method for controlling the cardiac rhythm of intact murine hearts of transgenic channelrhodopsin-2 (ChR2) mice using local photostimulation with a micro-LED array and simultaneous optical mapping of epicardial membrane potential.

通过在小鼠心脏中应用光遗传学多位点光刺激进行高级心律管理

Ventricular tachyarrhythmias are a major cause of mortality and morbidity worldwide. Electrical defibrillation using high-energy electric shocks is ...