Pav E, Hofecker G, Kment A, Niedermüller H
Aktuelle Gerontol. 1977 Oct;7(10):529-34.
II. Elasticity Parameters in Various Ages Power-extension diagrams of longitudinal and transversal stripes of the Aorta thoracica were recorded by means of an elctro-mechanical measuring instrument. The samples were taken from 108 male Sprague-Dawley rats aged 9, 15 and 24 months. The following parameters describing age-dependent alterations were calculated from the hysteresis loops of three consecutive extension-relaxation cycles: 1. the maximum power 2. the area of the first hysteresis loop 3. the characteristic of the relaxation-part of the third cycle. The maximum power and partly the areas of the hysteresis loops increased with age. The curves obtained by longitudinal stripes were approximated to a linear function (y = a + bx) plus a power-function (y = cxd). Their constants were explained as indices to the plasticity of the aorta, the retraction-power of the elastic fibres, the degree of the spiralization of the collagen fibres and the amount and/or the stability of the collagen. The ageing changes of these parameters indicated an increase of plasticity, an increase in the retraction-power of the elastic fibres, a rise of the pitch of the collagen spiral and an increase in the amount and/or in the stability of collagen. The curves from the extension of the transversal stripes revealed a different extension characteristic and could be described as the sum of two power functions. The causes of this different behaviour are not yet clearly understood.
二、不同年龄阶段的弹性参数
通过机电测量仪器记录了雄性Sprague-Dawley大鼠胸主动脉纵向和横向条纹的力-伸长图。样本取自108只年龄分别为9个月、15个月和24个月的雄性Sprague-Dawley大鼠。从三个连续拉伸-松弛循环的滞后回线计算出以下描述年龄依赖性变化的参数：1. 最大功率；2. 第一个滞后回线的面积；3. 第三个循环松弛部分的特征。最大功率以及部分滞后回线的面积随年龄增加。纵向条纹得到的曲线近似为线性函数（y = a + bx）加幂函数（y = cxd）。它们的常数被解释为主动脉可塑性、弹性纤维回缩力、胶原纤维螺旋化程度以及胶原量和/或稳定性的指标。这些参数的老化变化表明可塑性增加、弹性纤维回缩力增加、胶原螺旋间距增大以及胶原量和/或稳定性增加。横向条纹拉伸得到的曲线显示出不同的拉伸特征，可描述为两个幂函数的和。这种不同行为的原因尚未完全清楚。
