König M F, Lucocq J M, Weibel E R
Institute of Anatomy, University of Berne, Switzerland.
J Appl Physiol (1985). 1993 Oct;75(4):1877-83. doi: 10.1152/jappl.1993.75.4.1877.
To estimate the fraction of dense pulmonary capillary network that is perfused under physiological conditions, we developed a new method for the demonstration of in vivo capillary perfusion by light and electron microscopy. Blood plasma was labeled by 8-nm colloidal gold particles coated with rabbit serum albumin. In anesthetized rabbits, 4-5 ml of this tracer were injected into the right atrium. Two and 15 min later, the circulation was interrupted by a snare around the heart, and the lung was fixed by instillation with glutaraldehyde. Gold particles were found in the plasma space of alveolar capillaries as well as in other organs. A random sample of thin sections studied by electron microscopy revealed that the entire capillary bed of the lung was perfused at least with plasma within 2 min after tracer infusion. Light microscopy of silver-enhanced sections showed areas with different staining intensities but no obviously unperfused capillaries. The concept of capillary recruitment, which would require a significant fraction of capillaries unperfused at rest, may have to be reassessed to consider time factors as well as the two-phase nature of blood; red blood cells and plasma may take different paths.
为了估计在生理条件下灌注的致密肺毛细血管网络的比例，我们开发了一种通过光学显微镜和电子显微镜来证明体内毛细血管灌注的新方法。血浆用包被兔血清白蛋白的8纳米胶体金颗粒标记。在麻醉的兔子中，将4 - 5毫升这种示踪剂注入右心房。2分钟和15分钟后，通过环绕心脏的圈套器中断循环，并用戊二醛灌注固定肺。在肺泡毛细血管以及其他器官的血浆间隙中发现了金颗粒。通过电子显微镜研究的随机薄切片样本显示，在注入示踪剂后2分钟内，肺的整个毛细血管床至少被血浆灌注。银增强切片的光学显微镜检查显示出染色强度不同的区域，但没有明显未灌注的毛细血管。毛细血管募集的概念，即需要相当一部分毛细血管在静息时未被灌注，可能需要重新评估，以考虑时间因素以及血液的两相性质；红细胞和血浆可能走不同的路径。
