DEVELOPMENT OF SLIT LASER MICROSCOPE FOR QUANTIFICATION OF TISSUE PO2 DISTRIBUTION

为了阐明氧在微血管中的传输和氧在骨骼肌中的分布，我们设计了一台具有氧依赖磷光猝灭技术的活体激光显微镜。将氧磷光探针注入全身血液，用光电倍增管测量由N_2/染料脉冲激光激发的直径为15微米的组织区域的磷光。体外和活体氧分压(PO2)测量表明，这种方法的效率，因为它的非侵入性，准确性和快速反应时间。这项技术被应用于大鼠微循环中的PO2测量。测量动脉和静脉血氧分压(PO2)，按分支顺序进行分类。不同级别的平均动脉血氧分压随血管分支的增加而降低(A1：72.4，A2：51.8，A3：44.1 mm Hg)，而静脉血氧分压与血管级别无关(V1：27.5，V2：28.6，V3：32.0 mm Hg)。邻近不同级别小动脉的间质血氧分压显著低于血管内血氧分压(I1：47.8、I2：35.8和I3：24.4)。总之，我们设计的新的活体显微镜被证明是阐明氧通过微血管的运输机制和氧在骨骼肌中分布的有效方法。此外，不同级别小动脉的PO2水平显著降低，以及血与组织交界处存在较大的PO2梯度，提示骨骼肌小动脉的平滑肌和/或内皮细胞的耗氧量可能较高。

To clarify the oxygen transport across the microvessel and oxygen distribution in the skeletal muscle, we have newly designed an intravital laser microscope with oxygen-dependent quenching of phosphorescence technique. The phosphorescence probe for oxygen was injected into the systemic blood, and phosphorescence excited by N_2/dye pulse laserin the tissue area of 15 mum in diameter was measured by a photomultiplier. In vitro and in vivo oxygen tension (pO2) measurements revealed the efficiency of this method because of its non-invasiveness, accuracy, and rapid response time. This technique was applied to pO2 measurements in the rat microcirculation. The arteriolar and venular pO2 measurements were performed at the several regions classified by branching order. The mean arteriolar pO2 of different orders decreased according to increase the branching(A1 : 72.4, A2 : 51.8 and A3 : 44.1 mmHg), however venular pO2 were independent on vessel orders(V1 : 27.5, V2 : 28.6 and V3 : 32.0 mmHg). Interstitial pO2 adjacent to arterioles of different orders were significantly lower than those of intravascular pO2 (I1 : 47.8, I2 : 35.8 and I3 : 24.4 mmHg). In conclusion our new designed intravital microscope was proved the effective method to clarify the mechanisms of oxygen transport across the microvessels and the oxygen distribution in the skeletal muscle. In addition, the existence of significant reduction of pO2 levels in arterioles of different orders and large pO2 gradients at the interface between blood and tissue suggest that oxygen consumption of the smooth muscle and/or endothelium in the skeletal muscle arteriole might be high.