Ou L C, Sardella G L, Hill N S, Thron C D
Department of Physiology, Dartmouth Medical School, Lebanon, New Hampshire 03756-0001.
J Appl Physiol (1985). 1993 Jun;74(6):3020-6. doi: 10.1152/jappl.1993.74.6.3020.
Chronic hypoxia increases the total blood volume (TBV) and pulmonary arterial blood pressure (Ppa) and induces pulmonary vascular remodeling. The present study was undertaken to assess how the pulmonary blood volume (PBV) changes during hypoxia and the possible role of PBV in chronic hypoxic pulmonary hypertension. A novel method has been developed to measure the TBV, PBV, and Ppa in conscious rats. The method consists of chronic implantation of a loose ligature around the ascending aorta and pulmonary artery, so that when the ligature is drawn tightly, it traps the blood in the pulmonary vessels and left heart and simultaneously kills the rat. The pulmonary veins are then ligated to separate the left ventricular blood volume from the PBV. This surgical approach, together with chronic catheterization of the pulmonary artery and the use of 51Cr-labeled red blood cells, allows measurement of TBV, PBV, and Ppa. This method has been used to analyze the relationships between TBV and PBV and between Ppa or right ventricular hypertrophy and PBV in two rat strains with markedly different TBV and Ppa responses to chronic hypoxia. PBV per given lung weight did not increase and even decreased during hypoxia despite marked increases in TBV. There was a close correlation between Ppa or right ventricular hypertrophy and PBV in the two strains of chronically hypoxic animals, suggesting that a greater PBV plays a significant role in the development of severe chronic hypoxic pulmonary hypertension in the altitude-susceptible Hilltop rats.
慢性缺氧会增加总血容量（TBV）和肺动脉血压（Ppa），并导致肺血管重塑。本研究旨在评估缺氧期间肺血容量（PBV）如何变化以及PBV在慢性缺氧性肺动脉高压中的可能作用。已开发出一种新方法来测量清醒大鼠的TBV、PBV和Ppa。该方法包括在升主动脉和肺动脉周围长期植入一个宽松的结扎线，这样当结扎线收紧时，它会捕获肺血管和左心内的血液并同时杀死大鼠。然后结扎肺静脉以将左心室血容量与PBV分开。这种手术方法，连同肺动脉的长期插管和使用51Cr标记的红细胞，使得能够测量TBV、PBV和Ppa。该方法已用于分析两种对慢性缺氧有明显不同TBV和Ppa反应的大鼠品系中TBV与PBV之间以及Ppa或右心室肥大与PBV之间的关系。尽管TBV显著增加，但在缺氧期间每单位肺重量的PBV并未增加甚至减少。在两种慢性缺氧动物品系中，Ppa或右心室肥大与PBV之间存在密切相关性，这表明更大的PBV在易受高原影响的山顶大鼠严重慢性缺氧性肺动脉高压的发展中起重要作用。
