测量压力容量环中的鼠标
Summary
该原稿描述压力 – 体积数据从小鼠收集的详细协议。
Abstract
理解的原因和心脏疾病的进展呈现给生物医学界一个显著挑战。鼠标的遗传灵活性提供了很大的潜力在分子水平上，以探索心脏功能。鼠标的体积小巧确实提供的问候一些挑战进行详细的心脏表型。小型化和技术进步等已在小鼠心脏评估可能的方法很多。在这些中，压力和体积的数据的同时集合提供心脏功能的详细的图片是不通过任何其他方式。此处压力 – 容积环数据的收集的详细过程进行说明。包括的是的测量和误差的潜在来源的基本原则的讨论。麻醉管理和手术方法非常详细，因为他们是获得高质量的血流动力学测量两个关键的讨论秒。血流动力学协议开发和数据分析的相关方面的原则也被解决。
Introduction
心血管疾病仍然是世界各地的1死亡率和发病率的一个显著原因。心脏的疾病，目前在开发新的治疗特别困难的挑战。在遗传学的进展提供了识别潜在的遗传贡献者多种心脏疾病发展的可能性。心血管系统的综合性质，要求这些遗传目标的完整的动物模型中进行验证。鼠标的遗传灵活性和低住房成本已经把它带到了最前沿的一个特定基因的生理作用的评估。鼠标的小尺寸提出了心脏功能评估一些独特的挑战。有几种方式，可以提供关于心脏功能的信息，但只有心室压力和体积的同时测量允许压力容积（PV）心室功能的循环分析。光伏全循环流心脏功能进行分析独立于其连接到脉管的;在确定特定遗传元件的功能作用的重要因素。
压力-体积环的评估已经用于实验和临床上多年和广泛的文献存在对这些数据的分析台2,3。光伏循环技术的鼠标适配一直小鼠心脏生理4-6的理解的重要进展。基于导管的光伏循环技术对夫妇一个压力传感器和采用电导估计心室容积。心室体积是通过检查在由导管产生的电场的变化来确定。心室为圆柱体，它的高度由在导管和半径电极之间的距离所限定的本方法的模型是由电场的传导通过血液中计算心室7-9。由导管测定的电导信号有两个分量。第一种是通过血液中的导通;这个变化与心室的体积，并构成用于确定心室体积的初级信号。第二成分通过，并沿着心室的壁由传导引起的。这就是所谓的并联电导，并且必须以确定的绝对心室容积中移除。有对压力-体积数据的在研究实验室的收集和用于计算和删除并行电导的方法两种市售系统在它们6,10,11之间的主要区别。电导导管需要高渗盐水的平行电导的计算的注入。此注入瞬时改变心室血液的导电性，而壁的导电性保持不变。从这个数据，可以判断从血液起源和什么电导信号的分量来自于室壁。这种方法假设平行电导不会在心动周期中发生变化。准入方法依赖于电场的相位变化来评估心室壁的整体音量信号的贡献。此方法依赖于多种用于血液和心肌确定最终体积的电导率预定常数，不过在心动周期中，使平行电导的连续的措施。这两个系统的提供左心室体积的良好估计和它们之间的差异不太可能是生理显著。心室和其他假设的圆柱模型渲染不一样准确其他方式这些基于导管的方法，但是这种数据设置在一个节拍逐节拍的基础是对心功能的负载独立措施的评价是至关重要的。
这里所概述的程序是在我的实验室中使用，并已进行了大量的研究探讨营养不良病12-18的基本病理生理机制提供的数据。下面概述的过程是一个可以被用于获得光伏环两个数据之一。虽然许多原则适用于任何一种方法，该协议将专注于开胸顶的方法;一个胸外协议已在别处19,20详细说明。而程序将详细描述的那样，重要的首要原则是与要么心脏或肺部损害最小暴露心脏。在整个协议的是要记住，这是一个非生存过程，并且具有一个心脏良好曝光为导管的正确放置极为重要的是非常重要的。
Protocol
执行任何在本协议中所描述的过程之前，获得由当地机构动物护理和使用委员会的批准。 1.安装试验装置 注意：在麻醉动物进行该程序和数据的质量成比例提供给动物的麻醉剂支持体的质量。该第一部分将详细介绍必要的设备和程序，以提供麻醉的小鼠的同时执行该协议。 选择麻醉协议。吸入麻醉剂有用于执行光伏回路分析许多有?…
Representative Results
按照惯例，体积绘制在X轴和压力对Y轴如图1中。从对体积绘制压力产生应类似于一个矩形的压力-容积环，代表在压力（等容的变化，即在垂直的边缘，当两个二尖瓣和主动脉阀关闭）。底部水平代表心室通过二尖瓣和上部水平部填充代表心室通过主动脉瓣排空。在90健康的野生型小鼠左心室压力- 110毫米汞柱，预计8000的最大DP / DT – 12000毫?…
Discussion
有在此过程中三个关键步骤：1）气管导管和适当的通风，2）颈静脉导管的安置，以及3）在左心室光伏导管的正确放置的位置。确定适当的呼吸频率提供通气支持的重要组成部分。清醒小鼠一般保持快速浅呼吸肺泡通气。一般情况下，通风老鼠将有更大的潮气量。从而较慢的呼吸速率是必需的。这很重要，因为太少的通风会导致呼吸性酸中毒和太多的通风会导致呼吸性碱中毒，这两个条件，这将?…
Disclosures
The authors have nothing to disclose.
Acknowledgements
笔者想从NHLBI（K08 HL102066和R01 HL114832）承认资金。
Materials
| Dumont 5/45 (2) | Fine Science Tools | 11251-33 | |
| Vessel Dilating Forceps | Fine Science Tools | 18153-11 | |
| Castroviejo Micro Dissecting Spring Scissor | Roboz Instruments | RS-5668 | |
| Octogon Forceps – Serrated/Curved | Fine Science Tools | 11041-08 | |
| Octogon Forceps – Serrated/Straight | Fine Science Tools | 11040-08 | |
| Dissector Scissors- Heavy Blade | Fine Science Tools | 14082-09 | |
| Transpore Surgical Tape | 3M | 1527-1 | |
| 3-0 Silk Suture | Fine Science Tools | 18020-30 | |
| TOPO Ventilator | Kent Scientific | TOPO | |
| Martin ME 102 Electrosurgical Unit | Harvard Apparatus | PY2 72-2484 | |
| Syringe Pump | Lucca Technologies | GenieTouch | |
| Stereomicroscope with boom stand | Nikon | SMZ-800N | |
| Thermocouple Thermometer | Cole Parmer | EW-91100-40 | |
| T/Pump Warm Water Recirculator | Kent Scientific | TP-700 | |
| ADVantage Pressure-Volume System | Transonic | ADV500 | |
| Data Acquision and Analysis | DSI | Ponemah ACQ-16 |
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Cite This Article
Townsend, D. Measuring Pressure Volume Loops in the Mouse. J. Vis. Exp. (111), e53810, doi:10.3791/53810 (2016).