Observation of Microcirculatory Disorders of the Hemorrhagic Rat Liver by Use of Fluorescence-Stained Gamma Globulins

Summary

Using two different fluorescent dyes coupled to serum albumin, the sinusoids of the rat liver (n = 36, ketamine-xylazin anesthesia) were first stained red with an RB-200 infusion. The spreading of the yellow-green plasma front in the acinus following FITC bolus application was then fixed by means of liquid N₂ and investigated with the background of the red-marked sinusoidal network (7μm cryostat cuts).

Under normovolemia, the convective front had a sharply defined, regular contour which spread over all of the acinus sections with an increasing perfusion period.

Some liver acini showed asymmetrical coloring toward the terminal branch, which was probably caused by vasomotion and flow redistribution as well as through the course of sinusoids situated perpendicular to the observation plane. Compared with intravital microscopic observations of superficial acini, a wider variety of sinusoidal network architecture can be observed within deeper tissue layers where groups of sinusoids run perpendicular to each other.

Under hemorrhagic hypotension (mean arterial pressure = 40 mmHg, lasting 90 min), plasma-perfused and nonplasma-perfused sinusoids lie adjacent to one another; the distinct contour of the convective front is absent. Despite intrasinusoidal erythrocyte aggregation and break-down of hepatic O₂ transport (91 % of the liver surface has a P02 value of 0 mmHg), the remaining circulation during hemorrhage is about 25% that of normal and is mainly established through the sinusoidal plasma flow.