Sasaki Nobuhiko, Horinouchi Hirohisa, Ushiyama Akira, Minamitani Haruyuki
Graduate School of Science and Technology, Keio University, Tokyo, Japan.
Keio J Med. 2012;61(2):57-65. doi: 10.2302/kjm.61.57.
Oxygen transport is believed to primarily occur via capillaries and depends on the oxygen tension gradient between the vessels and tissues. As blood flows along branching arterioles, the O(2) saturation drops, indicating either consumption or diffusion. The blood flow rate, the O(2) concentration gradient, and Krogh's O(2) diffusion constant (K) of the vessel wall are parameters affecting O(2)delivery. We devised a method for evaluating K of arteriolar wall in vivo using phosphorescence quenching microscopy to measure the partial pressure of oxygen in two areas almost simultaneously. The K value of arteriolar wall (inner diameter, 63.5 ± 11.9 μm; wall thickness, 18.0 ± 1.2 μm) was found to be 6.0 ± 1.2 × 10(-11) (cm(2)/s)(ml O(2)·cm(-3) tissue·mmHg(-1)). The arteriolar wall O(2) consumption rate (M) was 1.5 ± 0.1 (ml O(2)·100 cm(-3) tissue·min(-1)), as calculated using Krogh's diffusion equation. These results suggest that the arteriolar wall consumes a considerable proportion of the O(2) that diffuses through it.
氧气运输被认为主要通过毛细血管进行，并且取决于血管与组织之间的氧分压梯度。当血液沿分支小动脉流动时，O₂饱和度下降，这表明存在消耗或扩散。血流速率、O₂浓度梯度以及血管壁的克罗格O₂扩散常数（K）是影响O₂输送的参数。我们设计了一种在体评估小动脉壁K值的方法，利用磷光猝灭显微镜几乎同时测量两个区域的氧分压。发现小动脉壁（内径，63.5±11.9μm；壁厚，18.0±1.2μm）的K值为6.0±1.2×10⁻¹¹（cm²/s）（ml O₂·cm⁻³组织·mmHg⁻¹）。使用克罗格扩散方程计算得出小动脉壁的O₂消耗率（M）为1.5±0.1（ml O₂·100 cm⁻³组织·min⁻¹）。这些结果表明，小动脉壁消耗了相当一部分通过它扩散的O₂。
