猪→人异种心脏移植中相关血管的生物力学特性(英文)

Biomechanical properties of relevant blood vessels in the heterogeneic heart transplantation from swine to human

背景:同种心移植器官来源有限,短缺问题日益突出。目的:观察正常成人与不同月龄猪升主动脉一维载荷下的力学特性,为猪→人异种心脏移植吻合血管提供必要的生物力学实验基础。设计:开放性实验。单位:郧阳医学院解剖教研室。材料:实验于2002-04/2003-07在郧阳医学院医用生物力学实验室完成。人升主动脉取自无心血管疾病、18～30岁意外死亡的6例成年男性尸体(由郧阳医学院遗体捐赠中心提供)。选取1月龄同种猪42头(由郧阳医学院实验动物中心提供,动物质量合格证号:QN0202),普通食料饲养,分别于1,2,3,4,5,6,7月龄时屠宰,6头/次。解剖分离、原位测量各自体内长度后从主动脉瓣环基底平面至无名动脉起始处取下升主动脉(所有标本均未见到动脉粥样硬化表现),分5等份,取第2,4管段用于一维载荷的力学试验。方法:应用生物软组织力学试验机,对6例成年男性尸体和42头1～7月龄猪升主动脉进行一维载荷的力学试验,所有的血管段试样均以相同的应变率于室温32℃进行预处理10次(载荷范围0～0.5N)。血管受到周期性的匀速的加载和卸载后滞后现象消失,得到可重复性的力-变形数据。用相同的载荷范围和应变率对血管进行1次加载和卸载,记录力-变形数据后,供计算机分析。每次结束后均用标准砝码和百分表对力和位移量进行标定。由实验数据来拟合材料常数α与弹性模量dT/dλ。主要观察指标:①人与不同月龄猪升主动脉一维载荷下力学特性常数的测定结果比较。②人与不同月龄猪升主动脉一维载荷下弹性模量的测定结果比较。结果:①人与不同月龄猪升主动脉一维载荷下力学特性常数的测定结果比较:随着月龄的增长,猪血管的材料常数虽有所增加,但差异无显著性意义(P>0.05)。人与1～7月龄猪升主动脉一维载荷下力学材料常数比较基本相似(P>0.05)。②人与不同月龄猪升主动脉一维载荷下弹性模量的测定结果比较:随着月龄的增长,7月龄猪升主动脉的弹性模量较其他月龄猪明显升高(P<0.05);人与各月龄猪的相应血管相比,弹性模量差异无显著性意义(P>0.05)。结论:人与1～7月龄猪升主动脉力学特性常数和弹性模量无明显差异,至少在某些区段二者相应血管的力学特性是相近的。从力学角度分析,猪→人异种心脏移植过程中人与猪相应升主动脉的吻合具有一定的可行性。

BACKGROUND： The source of conspecific heart transplantation organ is very limited and deficiency becomes more and more obvious. OBJECTIVE： To observe the mechanical properties of ascending aorta at one-dimensional loading between healthy persons and swine of different months, so as to provide necessary biomechanical experimental basis for anastomosing blood vessel in heterogeneic heart transplantation from swine to human. DESIGN： Open design SETTING： Staff Room of Anatomy, Yunyang Medical College MATERIALS： This experiment was carried out at the Laboratory of Biomechanics, Yunyang Medical College from April 2002 to July 2003. Ascending aortas of human were obtained from the 6 adult male corpses without cardiovascular diseases, aged 18 to 30 years, who died for accident and donated by Yunyang Medical College. Totally 42 eonspecific swine of 1 month old, with certification number of QN0202, were provided by Animal Experimental Center of Yunyang Medical College. They were raised with common foodstuff. The 42 swine were butchered respectively at 1,2,3, 4,5,6 and 7 months, 6 swine once. After anatomical isolation and in situ measurement of respective in vivo length, ascending aorta from aorta valve ring base plane to initiation part of innominate artery was taken out （Artherosclerosis was not presented in all the samples） and divided into five equal segments, and the second and fourth segments were used for mechanical test of one-dimensional loading. METHODS： Six adult male corpses and ascending aorta of 42 swine of 1 to 7 months were performed mechanical test of one-dimensional loading. All the blood segments were pre-treated ten times with the same strain rate at room temperature 32℃（loading range from 0 to 0.5 N）. Hysteresis disappeared after blood vessel was given periodic permanent loading and unloading, and repeated force-deformed data were obtained. Blood vessel was given loading and unloading once with the same loading range and strain rate. The recorded force-deformed data were used for computer analysis. Force and displacement were scaled with standard weight and percentage scale at the end of each time. Constant o： and elastic modulus dT/dh were fitted from experimental data. MAIN OUTCOME MEASURES： （1） Comparison of the mechanical characteristic constant of ascending aorta at one-dimensional loading between human and swine of different months. （2） Comparison of elastic modulus of ascending aorta at one -dimensional loading between human and swine of different months. RESULTS： （1） Comparison of the mechanical characteristic constant of ascending aorta at one-dimensional loading between human and swine of different months： With the increase of month, although the material constant of blood vessel of swine had a little increase, there was no significant difference （P 〉 0.05）. The mechanical material constant of ascending aorta at one-dimensional loading of human was basically familiar to that of swine of 1 to 7 months （P 〉 0.05）. （2） Comparison of elastic modulus of ascending aorta at one -dimensional loading between human and swine of different months： With the increase of months, elastic modulus of ascending aorta was significantly increased in swine of 7 months old in comparison with that in other months old （P 〈 0.05）; there was no significant difference of elastic modulus of corresponding blood vessel between human and swine of different months （P 〉 0.05）. CONCLUSION： There is no significant difference in mechanical characteristic constant and elastic modulus of ascending aorta between human and swine of 1 to 7 months. Mechanical characteristics of corresponding blood vessel were similar in some segments at least. From the mechanical angle, anastomosis of corresponding ascending aorta in the process of heterogeneic heart transplantation from swine to human has certain feasibility.