Nugent William H, Song Bjorn K, Pittman Roland N, Golub Aleksander S
Department of Physiology and Biophysics, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA 23298, USA.
Department of Physiology and Biophysics, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA 23298, USA.
Microvasc Res. 2016 May;105:15-22. doi: 10.1016/j.mvr.2015.12.007. Epub 2015 Dec 9.
Under physiologic conditions, microvascular oxygen delivery appears to be well matched to oxygen consumption in respiring tissues. We present a technique to measure interstitial oxygen tension (PISFO2) and oxygen consumption (VO2) under steady-state conditions, as well as during the transitions from rest to activity and back. Phosphorescence Quenching Microscopy (PQM) was employed with pneumatic compression cycling to achieve 1 to 10 Hz sampling rates of interstitial PO2 and simultaneous recurrent sampling of VO2 (3/min) in the exteriorized rat spinotrapezius muscle. The compression pressure was optimized to 120-130 mmHg without adverse effect on the tissue preparation. A cycle of 5s compression followed by 15s recovery yielded a resting VO2 of 0.98 ± 0.03 ml O2/100 cm(3)min while preserving microvascular oxygen delivery. The measurement system was then used to assess VO2 dependence on PISFO2 at rest and further tested under conditions of isometric muscle contraction to demonstrate a robust ability to monitor the on-kinetics of tissue respiration and the compensatory changes in PISFO2 during contraction and recovery. The temporal and spatial resolution of this approach is well suited to studies seeking to characterize microvascular oxygen supply and demand in thin tissues.
在生理条件下，微血管的氧气输送似乎与呼吸组织中的氧气消耗良好匹配。我们提出了一种在稳态条件下以及从静息到活动再恢复的过程中测量组织间氧张力（PISFO2）和氧气消耗（VO2）的技术。采用磷光猝灭显微镜（PQM）结合气动压缩循环，以实现对大鼠体外斜方肌组织间PO2的1至10Hz采样率以及VO2的同步重复采样（3次/分钟）。将压缩压力优化至120 - 130 mmHg，且对组织制备无不良影响。5秒压缩随后15秒恢复的周期产生的静息VO2为0.98±0.03 ml O2/100 cm³·min，同时保持微血管的氧气输送。然后使用该测量系统评估静息状态下VO2对PISFO2的依赖性，并在等长肌肉收缩条件下进一步测试，以证明其具有强大的能力来监测组织呼吸的启动动力学以及收缩和恢复过程中PISFO2的代偿性变化。这种方法的时间和空间分辨率非常适合旨在表征薄组织中微血管氧气供需情况的研究。
