Karlinsky J B
Department of Veterans Affairs Medical Center, Boston, MA 02130.
Respir Physiol. 1992 Dec;90(3):251-60. doi: 10.1016/0034-5687(92)90106-7.
A simple mathematical model of the one dimensional, stress-strain behavior of hamster lung tissue based on strain energy considerations was tested in degassed, uniaxially stretched strips obtained from normal and emphysematous hamster lungs cycled in saline. The relationship between Eulerian stress (sigma) and extension ratio (lambda) was found to take the form sigma = (lambda 2-1/lambda) x f(lambda) where the function f(lambda) was experimentally determined. Stress in six normal and five emphysematous strips was calculated by dividing the tension at each stretch increment by the strip cross-sectional area. Plotting sigma lambda/(lambda 2-1) versus a function of the form e eta lambda yielded a linear expression for f(lambda), me eta lambda + b, where n = 2. The complete stress-strain behavior of hamster lung strip tissue could then be expressed as a simple function of lambda over a range of lambda = 1.0-2.0: sigma = (lambda 2-1/lambda)(me2 lambda+b) The values of the constants m and b depend solely upon the mechanical properties of the elastic and collagen fiber networks in these atelectatic, saline cycled lung strips. The slope m = 0.151, and the intercept b = 0.416 in normal strips (r = 0.98). In emphysematous strips m = 0.016 and b = -0.199 (r = 0.82). Given the smaller m found for emphysematous strips, less strain energy accumulated with increasing stretch and did not even begin in these strips until lambda = 1.3. Further, the fit of the equation to the data was not as good for emphysematous as for normal strips. We conclude that the above equation adequately describes the stress-strain properties of normal hamster lung strips tissue but is not as good in emphysematous strips where the disease is patchy.
基于应变能考量，建立了一个描述仓鼠肺组织一维应力 - 应变行为的简单数学模型，并在从正常和肺气肿仓鼠肺中获取的、在盐水中循环的脱气单轴拉伸条带上进行了测试。发现欧拉应力（σ）与伸长比（λ）之间的关系形式为σ = (λ² - 1/λ) × f(λ)，其中函数f(λ)通过实验确定。通过将每个拉伸增量处的张力除以条带横截面积，计算了六个正常条带和五个肺气肿条带中的应力。绘制σλ/(λ² - 1) 与eηλ形式的函数关系图，得到了f(λ)的线性表达式，即mηλ + b，其中n = 2。然后，仓鼠肺条带组织的完整应力 - 应变行为可以表示为在λ = 1.0 - 2.0范围内λ的简单函数：σ = (λ² - 1/λ)(m2λ + b)。常数m和b的值仅取决于这些肺不张、在盐水中循环的肺条带中弹性和胶原纤维网络的力学性能。正常条带中斜率m = 0.151，截距b = 0.416（r = 0.98）。肺气肿条带中m = 0.016，b = -0.199（r = 0.82）。鉴于在肺气肿条带中发现的m较小，随着拉伸增加积累的应变能较少，并且直到λ = 1.3这些条带中才开始积累。此外，该方程对数据的拟合在肺气肿条带中不如在正常条带中好。我们得出结论，上述方程充分描述了正常仓鼠肺条带组织的应力 - 应变特性，但在疾病呈斑片状的肺气肿条带中效果不佳。
