离体心肌粘弹性的印压蠕变试验检测及其病理机制研究

Viscoelasticity of myocardium through indentation creep test in vitro and the analysis of its pathological mechanism

目的通过生物力学实验和印压方法检测正常和心肌梗死心肌粘弹性的改变及其病理机制分析。方法应用自行研制的印压实验装置通过印压蠕变试验分别检测保持活性的离体犬陈旧性梗死心肌(OMI组)和正常心肌(正常组)试件粘弹性特征参数(E、E1、E2、η、τ);并检测试件胶原含量、胶原容积分数(CVF)及I/III型胶原纤维比例。对心肌粘弹性参数与胶原含量、CVF、I/III型胶原比例分别进行相关分析。结果 OMI组粘弹性特征参数(E、E1、E2、η)、胶原含量、胶原容积分数、I/III型胶原比例均高于正常组,差异有统计学意义(P<0.05);两组胶原含量、CVF与E、E1、η呈高度正相关(P<0.05),正常组I/III胶原比例与E1、E呈高度正相关,OMI组则与E1呈正相关(P<0.05)。结论印压法可检测心室肌粘弹性特性;心肌梗死后弹性模量和粘性阻力均增高;心肌胶原增生及重构对心肌粘弹性有显著影响。

Objective To investigate the changes of myocardial viscoelasticity in normal and in myocardial infarction through biomechanical trial and indentation creep test, and analyze its pathological mechanism. Methods The viscoelastic characteristic parameters（ E,E1 ,E2,η,τ）of canine test pieces from old myocardial infarction （OMI group） and normal myocardium （normal group） were detected by indentation creep test with self-made load-deformation indentation experimental facility. At the same time, the collagen content,the collagen volume fraction （CVF） and the proportion of type I and III collagen were detected. Correlation analysis between the parameters of myocardial viscoelasticity and collagen content, CVF and type I/III collagen were carried out respectively. Results The viscoelastic parameters, collagen content, CVF and the ratio of collagen type I/III in the OMI group were significantly higher than that in the normal group （ P 〈 0. 05 ）. The highly positively correlations between the parameters of E/E1 and collagen content/CVF/collagen type I /III ratio were found （ P 〈 0. 05 ）. The highly negatively correlations between the parameters of E2/lq and collagen type I / III ratio were found （P 〈 0.05 ）. Conclusion It is feasible that the indentation creep test can be used to detect the myocardium vis- coelasticity. The elastic modulus and viscous resistance are increased after myocardial infarction. The proliferation and remodeling of my- ocardial collagen have a significant influence on myocardial viscoelasticity.