This study was supported by NIH grants HL091986 (JPD) and HL094692 (MTZ).

注：此动物议定书批准的机构动物护理和使用委员会（IACUC）在俄亥俄州立大学。此过程可用于在任何小鼠中，在颈动脉的内径大到足以插入导管。用小鼠是超过16克（超过〜2个月）。 1.准备鼠标导尿<ol><li>密封所有手术器械和用品的消毒袋。消毒在高压釜中的机器的小袋。保持整个过程的无菌区域和戴无菌手套。 </li><li>麻醉小鼠用氯胺酮（55毫克/千克）加赛拉嗪（15毫克/千克）通过腹膜内注射。 注：整个过程同时测量压力/容积在不同的心脏速率和ESPRV只需要不到20分钟。如果需要额外的时间（ 即 ，超过30分钟以上），得到另外¼剂量麻醉的每30分钟。 </li><li>除去毛在前ř颈部和胸部区域使用毛发去除洗剂（ 例如 ，奈尔）和egion胶带将小鼠的肢体上的泡沫平台。由脚趾捏确认深度麻醉状态。 </li><li>插入直肠探针监测体温（37±1℃），并保持使用热调节的加热垫（位于外科被单和平台之间）。 </li><li>准备4-0缝合线（约10厘米）长。绕上门牙环缝合带与平台。这将保持颈部挺直。 </li><li>通过擦拭用聚维酮碘和75％乙醇的三倍区域消毒的手术区域。 </li></ol> 2.导尿<ol><li>通过预浸泡的尖端在盐水或蒸馏水（37℃）至少30分钟制备的导管使用（根据制造商的说明），以适应新环境的压力传感器膜片的湿生物环境和防止压力信号漂移和负前压力记录。 </li><li>使下颚和胸骨在颈部的前部区域之间的纵向0.8厘米切口。随着精剪，分离皮肤，肌肉结缔组织揭露设下的肌肉stemohyoideus气管。 </li><li>在右侧与弯钳气管分离脂肪和肌肉组织以暴露右颈动脉。 注：颈动脉是颈部前区最大的动脉，包含了鲜红的血，是搏动。不要混淆与平行延伸到颈动脉颈内静脉。颈静脉是暗红色和非搏动。此外，在颈动脉的隔离期间，用户应该意识到不损害迷走神经的。 </li><li>从右颈动脉与弯曲镊子去除脂肪。如果存在分支，这将阻碍该操作技术的船只，切断他们与bovie刀烧灼分离颈动脉。分离尽可能多的组织尽可能使用弯钳颈动脉之下。 </li><li>切两5厘米6-0丝线。通过右颈总动脉下的每个丝线。 </li><li>位置一个线程邻近近端部分和其他邻近动脉的远端部分。使线程上紧结在远端部分，并且使线程上的松散的结在近端部分。 </li><li>通过夹紧用小止血血管钳动脉的近端部分阻塞血流（将近端螺纹下方的夹具）。动脉的密封区域将充满血液使其易于执行步骤2.8。 </li><li>穿刺一个小孔在两个线程（但更靠近所述远端螺纹）之间的右颈动脉用一个＆G针。插入导管插入颈动脉。略微收紧松散结在颈动脉的近端部分上的导管保持在适当位置。 注：使用穿刺是首选比较剪刀切口。通过使紧结在动脉的远端部分，然后再夹紧近端部分，动脉将被完全充满血液。这使得它非常容易捅血管。此外，该针（26 G）的大小穿刺与很好地配合在导管的尺寸的孔的动脉。当使用剪刀切口的方法，它是更加难以控制切口的大小。但是，选择的方法应该是取决于哪一个外科医生感觉更舒服。 </li><li>开始录制的压力信号，在第3步。 </li><li>松开止血钳，继续向前插入导管进入左心室。如果推进导管当一些阻力经历，轻轻拉回来，然后再试一次推进。对于一个小鼠体重〜18-25克，所插入的导管的估计长度为18毫米。 注：动脉压信号会波动从70至120毫米汞柱。一旦牛逼他导管是在左心室的压力信号的变化的形状和压力会波动，从0到120毫米汞柱（ 图1中示出）。心脏功能将插入导管后的2-3分钟稳定。 </li><li>连续监测体温，麻醉水平，和呼吸率。 </li></ol> 3.数据采集<ol><li>使用LabChartPro 7软件（或类似软件）。使用PV环LabChart模块的工作流程选项。使用此模块中，选择压力和容积循环默认设置。 </li><li>建立三个通道：一个通道的压力，一个通道音量，和一个通道对心脏率。以上参数为0-150毫米汞柱，0-100微升和0-800次/分钟，分别设定量程范围。 </li><li>按开始键记录。 </li></ol> 4.鲍迪奇影响<ol><li>制成1厘米的切口平行于所述柄的心前区面积。切断肌肉和EXP层OSE的肋间用剪刀。 </li><li>采用方波脉冲刺激，设置以下参数：电压为2 V，2毫秒的时间，并启用重复模式。 </li><li>握住钳子负极，并通过第四肋间隙心脏的心尖区插入。持用钳子的正极，并通过第二肋间到心脏的右心房区域插入。 </li><li>打开刺激器，改变频率，从4赫兹（240次/分）起搏心脏高达10赫兹（600次/分）。在每一个新的心脏率，刺激心脏进行数据采集前1分钟。 </li></ol> 5.生成ESPVR和PRSW <ol><li>切开皮肤和肌肉组织垂直于用剪刀腹部区域的柄。打开enterocoelia并露出肝脏。 </li><li>拖动弓costarum朝向头部采用金属牵引。 </li><li>轻轻地向下肝脏与推棉签。小心不要推太多影响胸腔。这将改变心脏功能。 </li><li>割肝的镰状韧带用剪刀以暴露肝上下腔静脉（IVC）。 </li><li>用弯钳迅速挤压下腔静脉，持续5秒，以阻断血液回流到右心房。左心室压力和容积将下降，由于减少了流入到心脏。在产生这些值，不要使用低于60毫米汞柱循环。 60毫米汞柱是在参考收缩压。 注意：此值被设定为60毫米汞柱，因为这将导致在灌注压一个显著下降到显着降低冠状动脉灌注和影响收缩力。 </li></ol> 6.音量校正<ol><li> Heparinize的小鼠用0.1ml的1：5000肝素溶液（用生理盐水稀释）通过腹膜内注射。 </li><li>从颈动脉取出导管。当导管被拉出FR嗡颈动脉，肝素化血液会渗入从插入导管，其中该孔。 </li><li>收集这些血用1毫升注射器体积校准。每个校准比色皿井填。 </li><li>删除通过心脏放血安乐死鼠标。 </li><li>定位在每个导管孔，并获得稳定的相对体积单元（RVU）值。生成使用各种标准体积和RVU值从每个孔的标准曲线。 </li><li>转换录制的RVU到微升。 </li></ol> 7.数据处理<ol><li>为了检验效果鲍迪奇，从每个心脏率稳态压力/体积的痕迹。点击基线分析，以获得数据。 </li><li>对于ESPVR和PRSW数据，选择第一〜15压力/容积痕迹，单击闭塞分析软件来生成ESPVR和PRSW（用在LV舒张末期容积形成的压力的斜率）（工作行程的线性回归与舒张末期体积）的斜坡。 </li><li>兼顾环的形状。确保环没有角点或曲折关闭。这是不正确的导管放置或噪声过大的迹象。在实验过程中定期检查循环，以确保正在生成适当的压力和体积数据。 </li></ol>

<ol>
	<li>Janssen, P. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Myocardial+contraction-relaxation+coupling.">Myocardial contraction-relaxation coupling.</a> Am J Physiol Heart Circ Physiol. 299, H1741-H1749 (2010).</li><li>Roman, M. J., Devereux, R. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+noninvasive+measures+of+contractility+in+dilated+cardiomyopathy.">Comparison of noninvasive measures of contractility in dilated cardiomyopathy.</a> Echocardiography. 8, 139-150 (1991).</li><li>Hamlin, R. L., del Rio, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=dP/dt(max)--a+measure+of+'baroinometry.">dP/dt(max)--a measure of 'baroinometry.</a> J Pharmacol Toxicol Methods. 66, 63-65 (2012).</li><li>Feneley, M. P., 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=Comparison+of+preload+recruitable+stroke+work,+end-systolic+pressure-volume+and+dP/dtmax-end-diastolic+volume+relations+as+indexes+of+left+ventricular+contractile+performance+in+patients+undergoing+routine+cardiac+catheterization.">Comparison of preload recruitable stroke work, end-systolic pressure-volume and dP/dtmax-end-diastolic volume relations as indexes of left ventricular contractile performance in patients undergoing routine cardiac catheterization.</a> J Am Coll Cardiol. 19, 1522-1530 (1992).</li><li>Kass, D. 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=Comparative+influence+of+load+versus+inotropic+states+on+indexes+of+ventricular+contractility:+experimental+and+theoretical+analysis+based+on+pressure-volume+relationships.">Comparative influence of load versus inotropic states on indexes of ventricular contractility: experimental and theoretical analysis based on pressure-volume relationships.</a> Circulation. 76, 1422-1436 (1987).</li><li>Nemoto, S., DeFreitas, G., Mann, D. L., 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=Effects+of+changes+in+left+ventricular+contractility+on+indexes+of+contractility+in+mice.">Effects of changes in left ventricular contractility on indexes of contractility in mice.</a> Am J Physiol Heart Circ Physiol. 283, H2504-H2510 (2002).</li><li>Ziolo, M. T., Kohr, M. J., Wang, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nitric+oxide+signaling+and+the+regulation+of+myocardial+function.">Nitric oxide signaling and the regulation of myocardial function.</a> J Mol Cell Cardiol. 45, 625-632 (2008).</li><li>Barouch, L. 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=Nitric+oxide+regulates+the+heart+by+spatial+confinement+of+nitric+oxide+synthase+isoforms.">Nitric oxide regulates the heart by spatial confinement of nitric oxide synthase isoforms.</a> Nature. 416, 337-339 (2002).</li><li>Wang, H., 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=Neuronal+nitric+oxide+synthase+signaling+within+cardiac+myocytes+targets+phospholamban.">Neuronal nitric oxide synthase signaling within cardiac myocytes targets phospholamban.</a> Am J Physiol Cell Physiol. 294, C1566-C1575 (2008).</li><li>Georgakopoulos, D., 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=In+vivo+murine+left+ventricular+pressure-volume+relations+by+miniaturized+conductance+micromanometry.">In vivo murine left ventricular pressure-volume relations by miniaturized conductance micromanometry.</a> Am J Physiol. 274, H1416-H1422 (1998).</li></ol>

There are no competing financial interests.

此技术获得收缩的可靠措施的一个关键步骤是正确的导管放置到LV。如果导管被放置不正确，当左心室收缩的壁可接触导致非常高的，而不是生理，压力值造成的不规则形状的PV循环导管。如果需要的话，该导管可以旋转以实现正确的放置。这种技术的另一个关键步骤是确保鼠标得到适当的麻醉。如果鼠标在麻醉，这将大大降低心脏功能。鼠标与心脏率低于〜250次/分，可考虑在麻醉。此外，采血?...

心脏的目的是泵整个身体的血液满足微生物的代谢需求。由于这些要求都在不断波动（ 例如 ，运动时），心脏必须适应（ 即 ，增加心输出量）。心脏有无数的设计途径来完成这一壮举。黄金的方式达到心脏，这是通过增加心脏率（ 即 ，鲍迪奇效果）1。即，当一个人的心脏速率增加，这导致增加的收缩力，并增加了心输出量。因此，心脏功能极其取决于心脏率。不幸的是，心脏疾病（ 例如 ，心肌梗塞，肥大等 ）导致低劣的心脏功能，其中心脏因此将不能满足身体的代谢需要。心脏疾病是发病率和死亡率在西方社会的主要病因。该重述许多人类cardiomy动物模型opathies被用于研究分子机制和测试潜在疗法。要辨别这些机制，并确定是否治疗可能是可行的，研究者必须评估在体内的心脏功能。 有几种方法来评估心脏功能的体内 （ 例如 ，超声心动图，MRI 等 ），这经常测量射血分数，缩短分数，心输出量， 等等。然而，这些参数是高度依赖于后负荷，预压，和心脏速率除了 ​​收缩2。测量收缩是必不可少的在其原生环境中领悟心脏的内在属性。最大（DP / dt 最大值 ）率压力的发展使我们更接近了一步了解收缩。不幸的是，上升/ dt为还取决于心脏速率和负载条件3。因此技术已被开发用于测量负载（和心脏速率，参见贝尔流）心肌收缩力指数无关（ 即 ，收缩末期容积压力的关系（ESPVR）和预紧recruitable工作行程（PRSW））4-6。 ESPVR描述了可以通过心室在任何给定的LV体积要开发的最大压力。 ESPVR的斜率代表收缩末期弹性（EES）。 PRSW是脑卒中工作（由PV环封闭区域）与舒张末期容积的线性回归。这些程序是收缩的更准确和精确的测量相比的血流动力学参数，如射血分数，心输出量，和每搏输出量。 ESPVR和PRSW可以经由下腔静脉（IVC）的临时阻塞而获得。阻断IVC可以带有闭合胸腔进行，以避免改变对心脏功能胸膜内压力的作用。 增加心脏率也提高了收缩和舒张1。因此，比较experimenta之间心脏功能时，L基团（ 如 ±DP / DT），心脏率必须相似。但是，类似的心脏率通常不因各种条件（疾病，研究干预等 ）发生在每个动物。应当指出的是，麻醉（注射和吸入）降低心脏速率。作为心脏速率是收缩的主要决定因素，麻醉将大大影响收缩力。出于这个原因，我们描述我们的程序。此外，许多心肌病的特点是降低收缩储备（ 即降低鲍迪奇效应）。因此，心脏功能应测在一系列心脏率。这里，我们描述了如何使用一个刺激（带有闭合胸腔）来实现这些效果。 除了 ​​心脏速率，一氧化氮（NO）也是收缩7的重要调节剂。否是通过生产的酶称为NO合成酶（NOS）。我们和其他人已经表明，小鼠神经元NOS的基因敲除（NOS1 <s达&gt; - / - ）已经减弱心肌细胞在体内的心脏血流动力学8,9收缩。该小鼠将用于经由在不同的心脏速率执行的低压压力/体积分析程序来演示的左心室收缩测量。

<table border="0" cellpadding="0" cellspacing="0" width="688">
	<tbody>
		<tr height="22">
			<td height="22" style="height:22px;width:216px;">Name of Reagent/ Equipment</td>
			<td style="width:187px;">Company</td>
			<td style="width:119px;">Catalog Number</td>
			<td style="width:167px;">Comments/Description</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:216px;">Xlyzine 100mg/ml</td>
			<td style="width:187px;">Ana Sed</td>
			<td style="width:119px;">4821</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:216px;">Katamin 50mg/ml</td>
			<td style="width:187px;">Ketalar</td>
			<td style="width:119px;">310006</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="85">
			<td height="85" style="height:85px;width:216px;">Heparin</td>
			<td style="width:187px;">APP Pharmaceuticals</td>
			<td style="width:119px;">6003922</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="85">
			<td height="85" style="height:85px;width:216px;">4-0 silk thread</td>
			<td style="width:187px;">Surgical specialties</td>
			<td style="width:119px;">SP102</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="85">
			<td height="85" style="height:85px;width:216px;">6-0 silk thread</td>
			<td style="width:187px;">Surgical specialties</td>
			<td style="width:119px;">MBKF270</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="64">
			<td height="64" style="height:64px;width:216px;">Forceps</td>
			<td style="width:187px;">Fine Science Tools</td>
			<td style="width:119px;">11251-10</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="64">
			<td height="64" style="height:64px;width:216px;">Curve forceps</td>
			<td style="width:187px;">Fine Science Tools</td>
			<td style="width:119px;">11274-20</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:216px;">Scissors</td>
			<td style="width:187px;">Fine Science Tools</td>
			<td style="width:119px;">14090-09</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:216px;">Vascular clamp</td>
			<td style="width:187px;">Fine Science Tools</td>
			<td style="width:119px;">18555-03</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:216px;">Microscope</td>
			<td style="width:187px;">World precision instruments</td>
			<td style="width:119px;">PZM-3</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:216px;">Pressure catheter</td>
			<td style="width:187px;">Millar instruments</td>
			<td style="width:119px;">SPR-839</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:216px;">Pressure and volume system</td>
			<td style="width:187px;">Millar instruments</td>
			<td style="width:119px;">MPVS-300</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:216px;">PowerLab4/35</td>
			<td style="width:187px;">AD instruments</td>
			<td style="width:119px;">N12128</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:216px;">LabchartPro 7</td>
			<td style="width:187px;">AD instruments</td>
			<td style="width:119px;"></td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="22">
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cardiac catheterization in mice to measure the pressure volume relationship: investigating the bowditch effect

已创建模仿人类心脏疾病的动物模型来测试潜在的治疗策略。一个关键组成部分，以评估这些战略是考察其对心脏功能的影响。有几种技术在体内心脏力学（ 例如 ，超声心动图，压力/容积关系， 等等 ）来衡量。相比超声心动图，经由导管左实时左心室（LV）的压力/体积分析更精确，见地在评估LV功能。此外，LV压力/体积分析提供了在收缩（ 如 β肾上腺素能刺激）和病理损伤（ 如缺血/再灌注损伤）的操作来记录瞬间变化的能力。除了 ​​最大值（+ DP / dt）的和最小（-dP / dt）的压力变化在LV速率，LV功能通过多个负载无关的索引的准确评估（ 例如 ，收缩末压力体积的关系和预紧recruitable行程工作）可以实现。心脏速率对左心室收缩一个显著效果，使得增加的心脏速率是提高心输出量（ 即 ，鲍迪奇效应）的主要机制。因此，实验组之间比较血流动力学时，有必要具有类似心脏速率。此外，许多病车型的标志是在收缩储备的减少（ 即减少鲍迪奇效果）。因此，重要的信息可以通过确定增加心脏速率上收缩的影响而获得。我们和其他人的数据表明，神经元型一氧化氮合酶（NOS1）基因敲除小鼠已减少收缩。在这里，我们描述了测量左室压力/体积随用NOS1基因敲除小鼠模型心脏率的过程。

正常插入导管进入左心室是达到适当的压力和体积值的一个重要步骤。 如图1中所示，使用LabChart Pro 7中，是压力波形（形状和值）作为导管的推移从动脉进入心室的变化。 正确插入导管进入左心室后，将压力（P）和体积（V）中得到将被用来产生光伏回路的值（示于图2）。 利用这些压力值，从而改变收缩机制可以进行调查。 <st...

Watch this Scientific Journal Video about Cardiac Catheterization in Mice to Measure the Pressure Volume Relationship: Investigating the Bowditch Effect at JoVE.com

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

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 ...

cardiac-catheterization-mice-to-measure-pressure-volume-relationship

Research

JoVE Journal

Medicine

18.0K 次观看.  The Ohio State University. This article describes the measurement of murine left ventricular function via pressure/volume analysis at different heart rates.

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

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

Dobutamine is a &beta;-adrenergic agonist with an affinity higher for receptor expressed in the heart (&beta;1) than for receptors expressed in the arteries (&beta;2). When systemically administered, it increases cardiac demand. Thus, dobutamine unmasks abnormal rhythm or ischemic areas potentially at risk of infarction. 
Monitoring of heart function during a cardiac stress test can be performed by either ecocardiography or cardiac catheterization. The latter is an invasive but more accurate and informative technique that the former.
Cardiac stress test induced by dobutamine and monitored by cardiac catheterization accomplished as described here allows, in a single experiment, the measurement of the following hemodynamic parameters: heart rate (HR), systolic pressure, diastolic pressure, end-diastolic pressure, maximal positive pressure development (dP/dtmax) and maximal negative pressure development (dP/dtmin), at baseline conditions and under increasing doses of dobutamine.
As expected, in normal mice we observed a dobutamine dose-related increase in HR, dP/dtmax and dP/dtmin. Moreover, at the highest dose tested (12 ng/g/min) the cardiac decompensation of high fat diet-induced obese mice was unmasked.

We describe the protocol to perform a cardiac stress test induced by dobutamine and monitored by cardiac catheterization in normal mice. Also we show its application to unmask subclinical cardiac disease in high fat diet-induced obese mice.

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 ...

科研

医学

Measurement of the Pressure-volume Curve in Mouse Lungs

In recent decades the mouse has become the primary animal model of a variety of lung diseases. In models of emphysema or fibrosis, the essential phenotypic changes are best assessed by measurement of the changes in lung elasticity. To best understand specific mechanisms underlying such pathologies in mice, it is essential to make functional measurements that can reflect the developing pathology. Although there are many ways to measure elasticity, the classical method is that of the total lung pressure-volume (PV) curve done over the whole range of lung volumes. This measurement has been made on adult lungs from nearly all mammalian species dating back almost 100 years, and such PV curves also played a major role in the discovery and understanding of the function of pulmonary surfactant in fetal lung development. Unfortunately, such total PV curves have not been widely reported in the mouse, despite the fact that they can provide useful information on the macroscopic effects of structural changes in the lung. Although partial PV curves measuring just the changes in lung volume are sometimes reported, without a measure of absolute volume, the nonlinear nature of the total PV curve makes these partial ones very difficult to interpret. In the present study, we describe a standardized way to measure the total PV curve. We have then tested the ability of these curves to detect changes in mouse lung structure in two common lung pathologies, emphysema and fibrosis. Results showed significant changes in several variables consistent with expected structural changes with these pathologies. This measurement of the lung PV curve in mice thus provides a straightforward means to monitor the progression of the pathophysiologic changes over time and the potential effect of therapeutic procedures.

Here we present a protocol to simply and reliably measure the lung pressure-volume curve in mice, showing that it is sufficiently sensitive to detect phenotypic parenchymal changes in two common lung pathologies, pulmonary fibrosis and emphysema. This metric provides a means to quantify the lung&#8217;s structural changes with developing pathology.

在小鼠肺压力容积曲线的测量

In recent decades the mouse has become the primary animal model of a variety of lung diseases. In models of emphysema or fibrosis, the essential ...

Intrauterine Telemetry to Measure Mouse Contractile Pressure In Vivo

A complex integration of molecular and electrical signals is needed to transform a quiescent uterus into a contractile organ at the end of pregnancy. Despite the discovery of key regulators of uterine contractility, this process is still not fully understood. Transgenic mice provide an ideal model in which to study parturition. Previously, the only method to study uterine contractility in the mouse was ex vivo isometric tension recordings, which are suboptimal for several reasons. The uterus must be removed from its physiological environment, a limited time course of investigation is possible, and the mice must be sacrificed. The recent development of radiometric telemetry has allowed for longitudinal, real-time measurements of in vivo intrauterine pressure in mice. Here, the implantation of an intrauterine telemeter to measure pressure changes in the mouse uterus from mid-pregnancy until delivery is described. By comparing differences in pressures between wild type and transgenic mice, the physiological impact of a gene of interest can be elucidated. This technique should expedite the development of therapeutics used to treat myometrial disorders during pregnancy, including preterm labor.

Intrauterine Telemetry to Measure Mouse Contractile Pressure In Vivo

This manuscript provides a protocol for implanting telemeters in the mouse for the purpose of measuring intrauterine pressures during pregnancy.

宫内遥测来衡量鼠标收缩压力<em&gt;在体内</em

A complex integration of molecular and electrical signals is needed to transform a quiescent uterus into a contractile organ at the end of pregnancy. ...

Ultrasound Based Assessment of Coronary Artery Flow and Coronary Flow Reserve Using the Pressure Overload Model in Mice

Transthoracic Doppler echocardiography (TTDE) is a clinically useful, noninvasive tool for studying coronary artery flow velocity and coronary flow reserve (CFR) in humans. Reduced CFR is accompanied by marked intramyocardial and pericoronary fibrosis and is used as an indication of the severity of dysfunction. This study explores, step-by-step, the real-time changes measured in the coronary flow velocity, CFR and systolic to diastolic peak velocity (S/D) ratio in the setting of an aortic banding model in mice. By using a Doppler transthoracic imaging technique that yields reproducible and reliable data, the method assesses changes in flow in the septal coronary artery (SCA), for a period of over two weeks in mice, that previously either underwent aortic banding or thoracotomy. 
During imaging, hyperemia in all mice was induced by isoflurane, an anesthetic that increased coronary flow velocity when compared with resting flow. All images were acquired by a single imager. Two ratios, (1) CFR, the ratio between hyperemic and baseline flow velocities, and (2) systolic (S) to diastolic (D) flow were determined, using a proprietary software and by two independent observers. Importantly, the observed changes in coronary flow preceded LV dysfunction as evidenced by normal LV mass and fractional shortening (FS). 
The method was benchmarked against the current gold standard of coronary assessment, histopathology. The latter technique showed clear pathologic changes in the coronary artery in the form of peri-coronary fibrosis that correlated to the flow changes as assessed by echocardiography. 
The study underscores the value of using a non-invasive technique to monitor coronary circulation in mouse hearts. The method minimizes redundant use of research animals and demonstrates that advanced ultrasound-based indices, such as CFR and S/D ratios, can serve as viable diagnostic tools in a variety of investigational protocols including drug studies and the study of genetically modified strains.

Coronary flow reserve (CFR) is useful for assessment of myocardial oxygen demand and evaluation of cardiovascular risk. This study establishes a step-by-step transthoracic Doppler echocardiographic (TTDE) method for longitudinal monitoring of the changes in CFR, as measured from coronary artery in mice, under the experimental pressure overload of aortic banding.

冠脉流量和冠状动脉血流储备用小鼠压力超负荷基于模型的超声评估

Transthoracic Doppler echocardiography (TTDE) is a clinically useful, noninvasive tool for studying coronary artery flow velocity and coronary flow ...

Cardiac Magnetic Resonance Imaging at 7 Tesla

CMR at an ultra-high field (magnetic field strength B0&#160;&#8805; 7 Tesla) benefits from the signal-to-noise ratio (SNR) advantage inherent at higher magnetic field strengths and potentially provides improved signal contrast and spatial resolution. While promising results have been achieved, ultra-high field CMR is challenging due to energy deposition constraints and physical phenomena such as transmission field non-uniformities and magnetic field inhomogeneities. In addition, the magneto-hydrodynamic effect renders the synchronization of the data acquisition with the cardiac motion difficult. The challenges are currently addressed by explorations into novel magnetic resonance technology. If all impediments can be overcome, ultra-high field CMR may generate new opportunities for functional CMR, myocardial tissue characterization, microstructure imaging or metabolic imaging. Recognizing this potential, we show that multi-channel radio frequency (RF) coil technology tailored for CMR at 7 Tesla together with higher order B0 shimming and a backup signal for cardiac triggering facilitates high fidelity functional CMR. With the proposed setup, cardiac chamber quantification can be accomplished in examination times similar to those achieved at lower field strengths. To share this experience and to support the dissemination of this expertise, this work describes our setup and protocol tailored for functional CMR at 7 Tesla.

The sensitivity gain inherent to ultrahigh field magnetic resonance holds promise for high spatial resolution imaging of the heart. Here, we describe a protocol customized for functional cardiovascular magnetic resonance (CMR) at 7 Tesla using an advanced multi-channel radio-frequency coil, magnetic field shimming and a triggering concept.

7号特斯拉的心脏磁共振成像

CMR at an ultra-high field (magnetic field strength B0&#160;&#8805; 7 Tesla) benefits from the signal-to-noise ratio (SNR) advantage inherent at higher ...

Real-time Pressure-volume Analysis of Acute Myocardial Infarction in Mice

Acute myocardial infarction can lead to acute heart failure and cardiogenic shock. The evaluation of hemodynamics is critical for the evaluation of any potential therapeutic approach directed against acute left ventricular (LV) dysfunction. Current imaging modalities (e.g., echocardiography and magnetic resonance imaging) have several limitations since data on LV pressure cannot directly be measured. LV catheterization in mice undergoing coronary artery occlusion could serve as a novel method for a real-time evaluation of LV function.
At the beginning of the procedure, mice were anesthetized followed by endotracheal intubation. For LV catheterization, the right carotid artery was exposed via middle-neck incision. The catheter was introduced and placed into the LV cavity. Left thoracotomy was conducted and the left main coronary artery (LCA) was ligated. To induce reperfusion, the suture was released after 45 min. Pressure-volume data was recorded at all times.
Ligation of the LCA caused a decrease in LV systolic function as evidenced by a 30% reduction in stroke volume, LV ejection fraction (EF), and cardiac output. Maximum dP/dt as a parameter for LV contractility was also significantly reduced and diastolic function was severely impaired (minimum dP/dt -40%). Reperfusion over a period of 20 min did not lead to a complete recovery of LV function.
Real-time pressure-volume analysis served as a valid procedure for monitoring cardiac function during acute myocardial infarction in mice. Maintaining stable anesthesia and a standardized surgical approach was crucial to ensure valid results. As the early phase of acute myocardial infarction is critical for morbidity and mortality, the delineated method could be beneficial for preclinical evaluation of new strategies for cardioprotection.

Acute myocardial infarction in mice induces acute but incompletely characterized changes in left ventricular (LV) function. LV catheterization in mice undergoing coronary artery occlusion serves as a novel method for a real-time evaluation of LV function.

小鼠急性心肌梗死的实时压力容积分析

Acute myocardial infarction can lead to acute heart failure and cardiogenic shock. The evaluation of hemodynamics is critical for the evaluation of any ...

Combining Volumetric Capnography And Barometric Plethysmography To Measure The Lung Structure-function Relationship

Tools to measure lung and airways volume are critical for pulmonary researchers interested in evaluating the impact of disease or novel therapies on the lung. Barometric plethysmography is a classic technique to evaluate the lung volume with a long history of clinical use. Volumetric capnography utilizes the profile of exhaled carbon dioxide to determine the volume of the conducting airways, or dead space, and provides an index of airways homogeneity. These techniques may be used independently, or in combination to evaluate the dependence of airways volume and homogeneity on lung volume. This paper provides detailed technical instructions to replicate these techniques and our representative data demonstrates that the airways volume and homogeneity are highly correlated to lung volume. We also provide a macro for the analysis of capnographic data, which can be modified or adapted to fit different experimental designs. The advantage of these measures is that their advantages and limitations are supported by decades of experimental data, and they can be made repeatedly in the same subject without expensive imaging equipment or technically advanced analysis algorithms. These methods may be particularly useful for investigators interested in perturbations that change both the functional residual capacity of the lung and airways volume.

Here, we describe two measures of pulmonary function &#8211; barometric plethysmography, which allows the measurement of lung volume, and volumetric capnography, a tool to measure the anatomic dead space and airways uniformity. These techniques may be used independently or combined to assess airways function at different lung volumes.

体积摄影与气压面学相结合测量肺结构-功能关系

Tools to measure lung and airways volume are critical for pulmonary researchers interested in evaluating the impact of disease or novel therapies on the ...

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) ...

Cardiac Response to &#946;-Adrenergic Stimulation Determined by Pressure-Volume Loop Analysis

Determination of the cardiac function is a robust endpoint analysis in animal models of cardiovascular diseases in order to characterize effects of specific treatments on the heart. Due to the feasibility of genetic manipulations the mouse has become the most common mammalian animal model to study cardiac function and to search for new potential therapeutic targets. Here we describe a protocol to determine cardiac function&#160;in vivo using pressure-volume loop measurements and analysis during basal conditions and under &#946;-adrenergic stimulation by intravenous infusion of increasing concentrations of isoproterenol. We provide a refined protocol including ventilation support taking into account the positive end-expiratory pressure to ameliorate negative effects during open-chest measurements, and potent analgesia (Buprenorphine) to avoid uncontrollable myocardial stress evoked by pain during the procedure. All together the detailed description of the procedure and discussion about possible pitfalls enables highly standardized and reproducible pressure-volume loop analysis, reducing the exclusion of animals from the experimental cohort by preventing possible methodological bias.

Cardiac Response to &amp;#946;-Adrenergic Stimulation Determined by Pressure-Volume Loop Analysis

Here we describe a cardiac pressure-volume loop analysis under increasing doses of intravenously infused isoproterenol to determine the intrinsic cardiac function and the &#946;-adrenergic reserve in mice. We use a modified open-chest approach for the pressure-volume loop measurements, in which we include ventilation with positive end-expiratory pressure.

通过压力-体积环路分析确定心脏对β肾上腺素能刺激的反应

Determination of the cardiac function is a robust endpoint analysis in animal models of cardiovascular diseases in order to characterize effects of ...

Functional Assessment of the Donor Heart During Ex Situ Perfusion: Insights from Pressure-Volume Loops and Surface Echocardiography

Heart transplantation remains the gold standard treatment for advanced heart failure. However, the current critical organ shortage has resulted in the allocation of a growing number of donor hearts with extended criteria. These marginal grafts are associated with a high risk of primary graft failure and may benefit from ex situ perfusion before transplant. This technology allows for extended organ preservation using warm oxygenated blood perfusion with continuous metabolic monitoring. The only NESP device currently available for clinical practice perfuses the organ in an unloaded non-working state, which does not allow for functional assessment of the beating heart. We therefore developed an original platform of NESP in working mode conditions with adjustment of left ventricular preload and afterload. This protocol was applied in porcine hearts. Ex situ functional assessment of the heart was achieved with intracardiac conductance catheterization and surface echocardiography. Along with a description of the experimental protocol, we herein report the main results, as well as pearls and pitfalls associated with the acquisition of pressure-volume loops and myocardial power during NESP. Correlations between hemodynamic findings and ultrasound variables are of major interest, especially for further rehabilitation of donor hearts before transplantation. This protocol aims to improve the assessment of donor hearts to both increase the donor pool and reduce the incidence of primary graft failure.

Functional Assessment of the Donor Heart During Ex Situ Perfusion: Insights from Pressure-Volume Loops and Surface Echocardiography

A reliable noninvasive approach for functional assessment of the donor heart during normothermic ex situ heart perfusion (NESP) is lacking. We herein describe a protocol for ex situ assessment of myocardial performance using the epicardial echocardiography and conductance catheter method.

非原位灌注期间供体心脏的功能评估：来自压力-容量环和表面超声心动图的见解

Heart transplantation remains the gold standard treatment for advanced heart failure. However, the current critical organ shortage has resulted in the ...

心导​​管在小鼠测量压力体积的关系：调查的影响鲍迪奇

心导管在小鼠测量压力体积的关系：调查的影响鲍迪奇