Jones D P, Kennedy F G
Am J Physiol. 1986 Mar;250(3 Pt 1):C384-90. doi: 10.1152/ajpcell.1986.250.3.C384.
The influence of cellular shape, cellular O2 consumption rate, and intracellular diffusion coefficient for O2 on the magnitude of intracellular O2 gradients during hypoxia was analyzed with the model of Boag (Curr. Top. Radiat. Res. 5: 141-195, 1969) to determine whether these parameters could account for the experimentally measured O2 dependence curves for myoglobin (Mb) oxygenation and cytochrome a + a3 oxidation in heart cells. The analysis shows that the intracellular diffusion coefficient for O2 must be below 4 X 10(-6) cm2/s for a substantial intracellular gradient to occur. The intracellular diffusion coefficient was calculated from the difference in half-maximal oxidation (P50) values for isolated Mb and intracellular Mb and was found to be 1.76 X 10(-6) cm2/s. Use of this value and appropriate geometric models satisfactorily described the O2 dependence of Mb oxygenation and cytochrome a + a3 oxidation in cells over an eightfold range of O2 consumption rates. However, the analysis does not account for the correspondence of intracellular P50 values of Mb oxygenation and cytochrome a + a3 oxidation. This implies that there exists an intracellular heterogeneity of either Mb distribution, mitochondrial distribution, or mitochondrial respiratory characteristics. Such heterogeneity would further contribute to diffusion limitation of O2 supply during hypoxia and could be a major factor underlying the cardiac myocyte structure-function relationship.
利用博阿格模型（《辐射研究前沿》第5卷：141 - 195页，1969年）分析了细胞形状、细胞耗氧率以及细胞内氧气扩散系数对缺氧期间细胞内氧气梯度大小的影响，以确定这些参数是否能够解释实验测量得到的心肌细胞中肌红蛋白（Mb）氧合和细胞色素a + a3氧化的氧气依赖性曲线。分析表明，为了产生显著的细胞内梯度，细胞内氧气扩散系数必须低于4×10⁻⁶ cm²/s。通过分离的肌红蛋白和细胞内肌红蛋白的半最大氧化（P50）值差异计算出细胞内扩散系数，结果为1.76×10⁻⁶ cm²/s。使用该值和适当的几何模型，在八倍的耗氧率范围内令人满意地描述了细胞中肌红蛋白氧合和细胞色素a + a3氧化的氧气依赖性。然而，该分析并未解释肌红蛋白氧合和细胞色素a + a3氧化的细胞内P50值的对应关系。这意味着在肌红蛋白分布、线粒体分布或线粒体呼吸特性方面存在细胞内异质性。这种异质性将进一步导致缺氧期间氧气供应的扩散限制，并且可能是心肌细胞结构 - 功能关系的一个主要因素。
