肺动脉高压大鼠模型中右心室功能的综合超声心动图评估
Summary
本协议描述了肺动脉高压大鼠模型中右心室形态和功能的超声心动图特征。
Abstract
肺动脉高压（PAH）是一种由肺部小动脉血管收缩和重塑引起的进行性疾病。这种重塑导致肺血管阻力增加、右心室功能恶化和过早死亡。目前批准的PAH疗法主要针对肺血管扩张剂途径;然而，最近新兴的治疗方式集中在涉及疾病发病机制的其他新途径上，包括右心室（RV）重塑。允许对新疗法进行纵向评估的成像技术对于确定新药在临床前研究中的疗效非常有用。无创经胸超声心动图仍然是评估心脏功能的标准方法，并广泛用于啮齿动物模型。然而，由于其解剖位置和结构，右心室的超声心动图评估可能具有挑战性。此外，临床前啮齿动物模型中缺乏超声心动图的标准化指南，因此难以在不同实验室的研究中对RV功能进行统一的评估。在临床前研究中，大鼠久效（MCT）损伤模型被广泛用于评估治疗PAH的药物疗效。该协议描述了幼稚和MCT诱导的PAH大鼠中RV的超声心动图评估。
Introduction
PAH 是一种进行性疾病，定义为静息时的平均肺动脉压大于 20 mmHg1。PAH 的病理改变包括肺动脉 （PA） 重塑、血管收缩、炎症以及成纤维细胞活化和增殖。这些病理变化导致肺血管阻力增加，从而导致右心室重塑、肥大和衰竭2。PAH是一种复杂的疾病，涉及几种信号通路之间的串扰。目前批准的治疗PAH的药物主要针对血管扩张剂途径，包括一氧化氮-环鸟苷单磷酸途径、前列环素途径和内皮素途径。针对这些途径的疗法已被用作单一疗法和联合疗法3，4。尽管在过去十年中PAH的治疗取得了进展，但美国REVEAL 登记处的调查结果显示，新诊断患者的 5 年生存率很低5.最近，新兴的治疗方式集中在疾病修饰剂上，这些药物可以影响PAH中发生的血管重塑的多因素病理生理学，以期破坏疾病6。
PAH的动物模型是评估新药物治疗效果的宝贵工具。MCT诱导的PAH大鼠模型是一种广泛使用的动物模型，其特征是肺动脉血管重塑，这反过来又导致肺血管阻力增加和右心室肥厚和功能障碍7，8。为了评估新疗法的疗效，研究人员通常专注于右心室压力的终末评估，而不考虑PA压力，右心室形态和右心室功能的纵向评估。使用无创和非终末成像技术对于全面检查动物模型中的疾病进展至关重要。经胸超声心动图仍然是评估动物模型中心脏形态和功能的标准方法，因为与其他成像方式（如磁共振成像）相比，经胸超声心动图成本低且易于使用。然而，由于右心室位于胸骨阴影下方、其发达的小梁和解剖形状，因此对右心室的超声心动图评估可能具有挑战性，所有这些都使得难以描绘心内膜边界9，10，11。
本文旨在描述一种综合方案，以评估 Sprague Dawley （SD） 大鼠幼稚和 MCT 诱导的 PAH 的右心室尺寸、面积和体积以及收缩和舒张功能。此外，该协议详细介绍了一种评估正常和扩张右心房超声心动图尺寸的方法。
Protocol
Representative Results
Discussion
RV的超声心动图评估是筛选PAH动物模型中新疗法有效性的宝贵发现工具。深入表征RV结构和功能是必要的，作为治疗PAH地址RV重塑的新靶点4，14。本研究描述了一个详细的协议，可以成功表征RV的结构和功能。
复杂的结构几何形状和胸骨后面的位置使得右心室的超声心动图表征变得困难;因此，改进的超声心动图视图用于促进右心室可…
Divulgazioni
The authors have nothing to disclose.
Acknowledgements
这项工作得到了NHLBI K01 HL155241和AHA CDA849387的支持，授予作者P.C.R.。
Materials
| 0.9% sodium cloride injection USP | Baxter | 2B1324 | |
| Braided cotton rolls | 4MD Medical Solutions | RIHD201205 | |
| Depilating agent | Wallgreens | Nair Hair Remover | |
| Electrode gel | Parker Laboratories | 15-60 | |
| High frequency ultrasound image system and imaging station | FUJIFILM VisualSonics, Inc. | Vevo 2100 | |
| Isoflurane | MedVet | RXISO-250 | |
| Male sprague Dawley rats | Charles River Laboratories | CD 001 | CD IGS Rats (Crl:CD(SD)) |
| Monocrotaline (MCT) | Sigma-Aldrich | C2401 | |
| Rectal temperature probe | Physitemp | RET-3 | |
| Sealed induction chambers | Scivena Scientific | RES644 | 3 L size |
| Solid-state array ultrasound transducer | FUJIFILM VisualSonics, Inc. | Vevo MicroScan transducer MS250S | |
| Stainless steel digital calipers | VWR Digital Calipers | 62379-531 | |
| Ultrasound gel | Parker Laboratories | 11-08 | |
| Vevo Lab software | FUJIFILM VisualSonics, Inc. | Verison 5.5.1 |
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