Microcirculation in periportal and pericentral regions of lobule in perfused rat liver

A noninvasive method was developed to quantitate the vascular space and the fraction of fluid entering the liver via the hepatic artery or portal vein in periportal and pericentral regions of the lobule. Fluorescence of fluorescein-dextran measured with a light guide placed on the surface of livers perfused via the portal vein in situ correlated closely with liver vascular space (r = 0.85). Thus, fluorescein-dextran fluorescence can be used to measure vascular space. Livers were then perfused simultaneously via the hepatic artery and portal vein at flow rates of 8 and 24 ml/min, respectively. Fluorescein-dextran (12 microM) was infused via the hepatic artery and portal vein separately or simultaneously. The sum of fluorescence increases due to fluorescein-dextran infused via the artery and vein equaled the increases due to simultaneous infusion via the artery and vein. From these measurements, the fraction of fluid that entered the vascular space via the artery or the portal vein was calculated. Vascular space was similar in hilar and tip areas of the left lateral lobe; however, threefold more fluid entered the liver via the hepatic artery in hilar regions than in tip areas. Micro-light guides were placed on periportal and pericentral areas of the liver lobule to monitor fluorescein-dextran fluorescence. Fluorescence changes indicated that the vascular space was about twice as large in pericentral as in periportal areas, whereas the fraction of fluid that entered the liver via the hepatic artery was similar in both regions. In addition, morphometric analysis of sections of liver indicated that the vascular space was 60% greater in pericentral than periportal regions.(ABSTRACT TRUNCATED AT 250 WORDS)