下肢运动对腹主动脉瘤生物力学影响的定量研究

Proper exercise has overall benefits to the health and rehabilitation of cardiovascular system. While the increased blood flow velocity and high pressure would become fatal threats to abdomial aortic aneurysm in exercise. Then how to balance the pros and cons is definitely a big challenge in clinic.The primary question that must be answer is that: how does exercise influence the biomechanical environment in aneurysm and then induce the tissue remodeling or rupture of aneurysm? Aiming to answering this question,computational simulation, in vitro and in vivo experiments will be involved in this proposed project.Some main research issues are as follows: 1) the hemodynamic parameter alteration when low limb exercise conducts; 2) numerically study the biomechanical environment of abdominal aneurysm under different hemodynamic parameters conditions; 3) design in vitro experiments to study the influence of biomechanical alteration on biological features of artery and cells; 4) design animal models of abdominal aortic aneurysm to study the influence of exercise on aneurysm geometry and biomechanical features.The proposed project will extend the study of aneurysm biomechanics, which would contribute to full understanding of the mechanism of aneurysm formation and development. This proposed study would also provide more scientific instruction to the life style and post-operation rehabilitation of aneurysm patients.

适当的运动训练有助于心血管系统健康和康复，但是运动带来的血液流速增大、血压升高等因素又会对腹主动脉瘤造成严重甚至是致命威胁。利弊两方面如何平衡是临床中急需回答却又未能回答的问题。究其原因，最关键的是未能回答: 运动如何影响腹主动脉瘤的生物力学环境，进而引起其组织重建或破裂? 本项目拟通过计算机仿真、体外实验、动物实验等手段，定量研究: 1) 下肢不同运动强度下动脉瘤内血流参数变化规律: 2) 计算机仿真准确模拟不同血流参数下动脉瘤内的生物力学环境: 3) 体外实验研究运动引起的生物力学环境变化对血管及细胞生物学行为的影响：4) 构建腹主动脉瘤动物模型，研究运动对动脉瘤在体形态及力学行为的影响。本课题的顺利开展，将拓展腹主动脉瘤生物力学研究的范围，有助于更加全面地探究腹主动脉瘤形成和发展的生物力学机理。同时也可为腹主动脉瘤惠者的生活方式和术后康复提供更加科学的指导。

适当运动有利于心血管系统的健康和疾病康复，但对腹主动脉瘤（AAA）而言，运动带来的血液流速增大、血压升高可能是致命威胁，为探究下肢运动对AAA的影响，本研究用三种方法制备AAA模型：化学诱导联合流出道缩窄法、药物灌注损伤血管中膜层法、3D打印套管内药物浸润法。在上述试验的基础上，选择造模效率较高的药物灌注损伤血管中膜层法制备犬AAA模型，并观察强制下肢运动和使用去甲肾上腺素模拟下肢运动引起的血压变化对AAA的影响，结果显示：1. 运动可以有效增加AAA内血压，其会随着运动强度的增强而升高，并能在停止运动后快速下降，于30 min后恢复至运动前的状态；2. 运动能加快血流速度，增大腹主动脉瘤体壁面应力和壁面剪切力，有效改善血流动力学环境；3. 短期的运动训练不会导致腹主动脉瘤直径变大，反而在一定程度上抑制了腹主动脉瘤继续扩张。4. 去甲肾上腺素可有效增加腹主动脉瘤内血压和血流速度，加大瘤体壁面剪切应力，降低犬心率，减少瘤体中腔内血栓的形成；5. 去甲肾上腺素引起的血流动力学环境变化不会引起瘤体直径扩张，在本试验使用剂量范围内不会导致瘤体破裂；6. 去甲肾上腺素所引起的血流动力学环境变化有利于腹主动脉瘤血管组织进行重构；本研究结果为AAA快速造模及临床分析适量运动对AAA的影响提供理论依据。