左心房，主动脉和肺动脉的超声心动图小鼠
Summary
以下方案描述了用于获得左心房容积（LAV），主动脉（AO）的直径，以及肺动脉（PA）的直径在小鼠心脏超声图像的获取和分析的方法。这种技术是一种非侵入性的，非终端程序，允许心肺功能的评估。
Abstract
本方法教导研究者如何测量并使用LAV通过超声心动图中左心室舒张压慢性升高的替代，以及获得小鼠主动脉和PA直径的测量。
比的年龄10天老年小鼠中可以使用本技术进行分析。该技术是由3个主要步骤：设置，图像采集和图像分析。的设立步骤包括得到含有1％异氟烷麻醉小鼠，剃须它，并在仰卧位置到加热的EKG板，其中所述图像采集将于胶带它的。图像获取步骤包括学习以识别心脏结构和获得所有与它的相应探针和轴所需的图像，以便能够计算体积和直径。图像分析步骤包括在计算机软件的帮助下测定以前获得的图像。
<p class ="“jove_content”">所提出的技术的优点包括一个快速（15分钟）的过程，将允许研究者在非侵入性的，非端的方法评价干预并因此遵循随时间相同的鼠标;各小鼠可用作它自己的控制。这一事实加上具有相同操作者执行所有的采集和分析在整个实验操作者依赖性的限制最小化。目前的方法是在心血管和肺部医学研究人员的鼠标有用。Introduction
目前的方法教调查员如何衡量和使用LAV，主动脉直径和PA直径二维超声心动图小鼠下异氟醚。心脏衰竭与老年人射血分数（HFPEF）影响的那些80年高达10％及以上1和结果显著发病率和死亡率。显著的死亡率也由肺动脉高压（PH），一个阴险的疾病过程有类似症状HFPEF，其中肺动脉压力升高导致劳力性呼吸困难，进行正确的心脏衰竭，并经常提出的死亡发生。 2既HFPEF和PH值的日益流行表示用于开发了一种方法，允许在非侵入性，非终端的方法准确的评价，并在小鼠模型干预监测。
通过心室艺术改变老化导致舒张功能恶化erial硬化，血管功能障碍，炎症3，受损的钙调节4，降低β肾上腺素能响应性和身体功能失调产生积极的减缓放松和增加被动刚度。随着时间的推移这将导致增加的LV充盈压和洛杉矶的代偿性肿大。 五
虽然其他病因，如瓣膜功能不全（二尖瓣关闭不全或狭窄）和浸润工艺导致在LA 1压力和容积升高，欧洲心脏病学会支持添加LA大小为LV功能的无创性反映。 6
洛杉矶量和舒张功能的微创措施之间的相关性进行了研究，小鼠。在功能差异相关洛杉矶量确定侵入年龄组为14位和31个月之久的米冰。在14个月大的老鼠，LA体积舒张功能的三个标准侵入措施相关-dP / DTMIN（R 2 = 0.5，P <0.05），头（松弛时间常数（R 2 =。6， p <0.05），左室舒张末压（R 2 = 0.25，p <0.05）; 31个月大的老鼠，洛杉矶量和-dP / DTMIN（R 2 = 0.92，p之间的关系< 0.05），左室舒张末压（R 2 = 0.61，p <0.05），但明显与头的关系是不太清楚。因此，洛杉矶量不仅跨组，但年龄组中舒张功能障碍增加。7
在使用导管技术来评估心脏功能，虽然严格而可靠的，被限制的鼠模型的心脏功能的研究由于其与反复评估不相容性。 8替代侵入的措施，如MRI和三维超声心动图也可以是比2D超声心动图技术更准确，但它们比较昂贵; 2D超声心动图被认为足以洛杉矶量评估。 9，10
对LA体积和PA直径与超声心动图评估允许产生在肺动脉阻力主要增加导致与在洛杉矶的压力或LAV从那些没有变化的增加的PA直径，其中肺动脉和左心房都放大作为模型之间的区别对心脏的左侧充盈压升高的结果。这种方法是采取斯卡利亚等。谁发现，在人，超声心动图肺动脉左心房比（ePLAR）是给患者预先肺毛细血管高血压和capillaryhypertension柱之间精确区分的参数。 11
Protocol
Representative Results
Discussion
有成功测量LAV，主动脉和PA直径的三个关键步骤。在设定了它完全删除在胸前的毛皮是非常重要的;如果不这样做会导致图像质量的干扰。在图像采集步骤，重要的是获得具有其相应的探针和过滤器各图像每秒帧从探头变化来探测：即25兆赫和心脏筛选为LAV的评估和30兆赫和评估腹部过滤的主动脉和PA的直径。研究者有时由图像获取差如果鼠标具有的脂肪量很大，或者如果一个肋使得难以得到良好的?…
Declarações
The authors have nothing to disclose.
Acknowledgements
This work was supported by the Huffington Center on Aging at Baylor College of Medicine, Geriatrics, CVS DeBakey Heart Center at Houston Methodist Hospital and BCM, NIH RO-1 HL 13870 to ML Entman, as well as a Career Development Award # IK2BX002410 from the United States Department of Veterans Affairs (LMP), Biomedical Laboratory Research and Development Program.
We are immensely grateful to Mark Entman M.D. for sharing his wisdom and supporting this work.
Materials
| Vevo 770 high-resolution in vivo micro-imaging system | Visual Sonics | Vevo 770-120 | Echocardiographic Equipment |
| 707B RMV (Real time MicroVisualization) 30 MHz Scanhead with encapsulated transducer | Visual Sonics | 707B-256 | Real Time Microvisualization Scanhead |
| 710B RMV (Real time MicroVisualization) 25 MHz Scanhead with encapsulated transducer | Visual Sonics | 710B-159 | Real Time Microvisualization Scanhead |
| Vevo integrated rail system including physiological monitoring unit | Visual Sonics | ||
| Inhalation Anesthesia System | VetEquip | VE2627 | Anesthesia System |
| Isofluorane | Henry Schein | 50033 | |
| Electric razor | Wahl | General supply | |
| Hair removal cream | Nair | General supply | |
| Transductor cream | Parker | ||
| Transductor gel | Parker | ||
| Standard Gauze pads | McKeeson | General supply | |
| Tape | Durapore | General supply | |
| Nose cone | For anesthesia delivery | ||
| Water | |||
| Vet eye ointment | Puralube | General supply | To prevent dryness |
| Cotton tipped applicators | General supply | ||
| USB Flash Drive | General supply |
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