心脏异常的实验性自身免疫性心肌炎的无创性评估磁共振成像显微镜在鼠标
Summary
This study demonstrates the successful establishment of magnetic resonance microscopy imaging as a non-invasive tool to assess the cardiac abnormalities in mice affected with autoimmune myocarditis. The data indicate that the technique can be used to monitor the disease-progression in live animals.
Abstract
心肌炎是心肌的炎症，但对疾病的影响的那些表演的临床表现只〜10％。研究心肌损伤的免疫事件，心肌炎的各种小鼠模型已被广泛使用。这项研究涉及实验性自身免疫性心肌炎（EAM）诱导的心肌肌球蛋白重链（MYHC）-α的A / J小鼠334-352段;受影响的动物培养淋巴细胞性心肌炎，但没有明显的临床症状。在这个模型中，磁共振显微镜（MRM）作为一种非侵入性方式的实用程序来确定显示在免疫的动物MYHC-α334-352心脏结构和功能改变。 EAM和健康的小鼠用9.4 T（400兆赫）89 mm垂直芯孔扫描仪配备了4厘米千足虫射频成像探头和100克/厘米三轴梯度成像。从麻醉动物用梯度回波为基础的电影脉冲序列被收购心脏图像，和阿尼玛LS是由呼吸和脉搏血氧饱和度监测。该分析显示，增加心室壁在EAM小鼠的厚度，并相应减少心室的内部直径，当与正常小鼠相比较。该数据表明，在发炎的心脏形态和功能变化可能是由MRM非侵入性地监测在活的动物。总之，MRM提供评估引起的感染性疾病的药物的心肌损伤的进展和回归，以及响应于治疗的优点。
Introduction
心脏衰竭是死亡的主要原因，心肌炎是心脏衰竭的青春少年1一个最主要的原因。患有心肌炎患者大多没有症状和疾病自发缓解2。然而，那些受影响的10-20％可发展为慢性疾病，导致扩张性心肌病（DCM）3。各种动物模型已经发展到研究心肌炎的免疫发病机制。这种疾病可以通过免疫动物与心肌肌球蛋白重链（MYHC）-α或其免疫显性肽片段或通过与病原体如柯萨奇病毒B3 4-9感染诱导的心肌炎敏感的A / J和Balb / c小鼠。这项研究涉及MYHC-α在A / J小鼠334-352引起的心肌炎。尽管显示心肌浸润，心肌炎影响的动物出现临床表现正常;诊断依据心脏炎症7的组织学评价ND超声心动图10。
磁共振显微镜（MRM）是一种常用的方法，得到心血管成像具有高分辨率的三维平面上，允许的功能细节，以评估微小血管的水平（高达10微米直径），但分辨能力的这种电平是无法实现与常规的磁共振成像（MRI）扫描程序，其中，该分辨率通常是获得可达1毫米11-14。 MRM提供了一个优点，因为它允许获得的高分辨率图像，以及在疾病过程14的早期时间点获得的性能参数。在临床上，MRM成像已被广泛应用于研究的病变心脏，肺或脑部15-17功能参数。在这项研究中，显示了一个使用MRM技术作为一种非侵入性工具，以确定受影响的自身免疫性心肌炎的A / J小鼠的心脏异常。具体来说，T他MRM成像允许的功能参数如左室（LV）舒张末期容积和射血分数（EF）以合理的准确性18定量。各参数的定义如下：LV舒张末期容积，血容量在左心室的舒张周期的结束，和射血分数，每搏输出量/舒张末期容积。使用对通过磁共振扫描器19获取的处理符合DICOM标准的心血管图像而开发的免费提供的分类软件进行数据分析。该数据显示在心肌炎动物的增加左心室壁的厚度，对应于左室舒张末期容积，每搏输出量和射血分数下降，与健康小鼠这些功能参数进行比较。
Protocol
Representative Results
Discussion
这项研究描述为一种非侵入性工具，以确定心脏异常的影响与自身免疫性心肌炎小鼠的MRM过程及其效用。由于EAM的组织学特征类似于人类感染后心肌炎小鼠模型通常用来描绘心肌损伤23-25 的免疫机制。但是，患有心肌炎动物出现临床表现正常，诊断是基于在组织学实验7终止进行。动物通常是牺牲在21天接种后。评估这样的疾病过程在单个时间点的限制使用这些模型，尤其是在…
Divulgations
The authors have nothing to disclose.
Acknowledgements
This work was supported by the National Institutes of Health (HL114669). CM is a recipient of a postdoctoral research fellowship grant awarded by the Myocarditis Foundation, NJ.
Materials
| Myhc-a 334-352 (DSAFDVLSFTAEEKAGVYK) | Neopeptide, Cambridge, MA | Store at 4οC | |
| CFA | Sigma Aldrich, St Louis, MO | 5881 | Store at 4οC |
| MTB H37Rv extract | Difco Laboratories, Detroit, MI | 231141 | Store at 4οC |
| PT | List Biologicals Laboratories, Campbell, CA | 181 | Store at 4οC |
| 1x PBS | Corning, Manassas, VA | 21-040-CV | Store at 4οC |
| Isoflurane | Piramal Healthcare, Mumbai, India | NDC66794-013-25 | |
| Female A/J mice | Jackson Laboratories, Bar Harbor, ME | 646 | |
| Leur-lok sterile 1 ml syrringe | BD, Franklin Lakes, NJ | 309628 | |
| Leur-lok sterile 3 ml syrringe | BD, Franklin Lakes, NJ | 309657 | |
| Sterile needle, 18 G | BD, Franklin Lakes, NJ | 305195 | |
| Sterile needle, 27 1/2 G | BD, Franklin Lakes, NJ | 305109 | |
| 3-way stopcock | Smiths Medical ASD, Inc. Dublin, OH | MX5311L | |
| Kerlix gauze bandage rolls | Covidien, Mansfield, MA | 6720 | |
| Kimwipes | Kimberly-Clark Professional, Roswell, GA | 34155 | |
| Protouch Stockinette | Medline Industries, Mundelein, IL | 30-1001 | |
| Sterile surgical scissors and forceps | INOX tool Corporation | ||
| Micro oven | GE Healthcare, | ||
| ThermiPAQ hot and cold therapy system | Theramics Corporation, Springfield, IL | ||
| Reptile heating lamp | Energy Savers Unlimited, Inc. Carson, CA | ||
| 3M Transpore tapes | Target Corporation, MN | ||
| Up and Up Polymyxin B sulfate/Bacitracin/Neomycin sulfate antibiotic ointment | Target Corporation, MN | ||
| North Safety DeciDamp-2PVC foam ear plugs | North Safety Products, Smithfield, RI | ||
| Cotton tipped applicator, 6’’ wooden stem | Jorgensen Laboratories, Inc. Loveland, CO | ||
| Anesthesia induction chamber | Summit Anesthesia Solutions, Ann Harbor, MI | ||
| Summit Anesthesia Support system for regulating flow of anesthesia | Summit Anesthesia Solutions, Ann Harbor, MI | ||
| Specially designed animal holder | Agilent Technologies, Santa Clara, CA | ||
| Bickford Omnicon F/Air anesthesia gas filter unit | A.M. Bickford, Inc. Wales Center, NY | ||
| Pulse-oximeter module, MR compatible small animal monitoring and gating system | Small Animal Instruments, Inc. Stony Brook, NY | ||
| Oxygen cylinder | Matheson-Tri Gas, North-Central Zone, Lincoln, NE | ||
| Gas regulator | Western Medica, West Lake, OH | ||
| Signal breaking module, MR compatible small animal monitoring and gating system | Small Animal Instruments, Inc. Stony Brook, NY | ||
| 9.4 T (400 MHZ) 89 mm vertical core bore MR scanner | Agilent Technologies, Santa Clara, CA | ||
| 4-cm millipede micro-imaging RF coil | Agilent Technologies, Santa Clara, CA | ||
| SAM PC monitor | Small Animal Instruments, Inc. Stony Brook, NY | ||
| Quantitative Medical Image analysis software | http://segment.heiberg.se; Segment v1.8 R1430, Medviso, Oresunds region, Sweden | ||
| Matlab software | The Mathworks, Inc. Natick, MA | ||
| Computer-Unix operating system | |||
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