Turek Z, Rakusan K, Olders J, Hoofd L, Kreuzer F
Department of Physiology, Faculty of Medicine, Catholic University Nijmegen, The Netherlands.
J Appl Physiol (1985). 1991 Apr;70(4):1845-53. doi: 10.1152/jappl.1991.70.4.1845.
A model of myocardial oxygenation was developed that allows calculation of Po2 histograms under varying conditions. The model consists of parallel tissue cylinders with varying radii, simulating the heterogeneity of capillary spacing, in agreement with our previous experimental results. The facilitated diffusion of O2 by myoglobin, an additional resistance to diffusion at the capillary level, and the Michaelis-Menten type of O2 consumption were also incorporated. The shape of the histograms depends on input data. When no additional barrier to O2 transport is included, the histograms resemble those obtained with Po2 surface electrodes, and they are strongly dependent on heterogeneity in capillary spacing and capillary blood flow. On the other hand, an inclusion of an additional capillary barrier combined with the Michaelis-Menten type of O2 consumption can generate Po2 histograms similar to those derived from myoglobin cryospectroscopy. In this case, the Po2 histograms are relatively independent of heterogeneity of capillary spacing and blood flow. The facilitation of O2 diffusion by myoglobin has only a modest effect on the form of the histograms in all situations considered.
我们开发了一种心肌氧合模型，该模型能够计算不同条件下的氧分压直方图。该模型由不同半径的平行组织圆柱体组成，模拟毛细血管间距的异质性，这与我们之前的实验结果一致。模型还纳入了肌红蛋白对氧气的易化扩散、毛细血管水平的额外扩散阻力以及米氏类型的氧气消耗。直方图的形状取决于输入数据。当不包含氧气传输的额外屏障时，直方图类似于用氧分压表面电极获得的直方图，并且它们强烈依赖于毛细血管间距和毛细血管血流的异质性。另一方面，纳入额外的毛细血管屏障并结合米氏类型的氧气消耗，可以生成与从肌红蛋白低温光谱学得出的类似的氧分压直方图。在这种情况下，氧分压直方图相对独立于毛细血管间距和血流的异质性。在所有考虑的情况下，肌红蛋白对氧气扩散的促进作用对直方图的形式只有适度的影响。
