A model for provoking ischemic necrosis in rat liver parenchyma and its quantitative analysis.

Ischemia in the left lateral and median lobe of the rat liver was provoked by means of a small clip, as applied in human microvascular surgery. After various periods of ischemia (30, 40, 50, 60 and 90 min) the blood flow to these lobes was restored. Twenty-four hours after restoration, the extent of necrosis was estimated quantitatively via morphometric measurements of the relative surfaces of necrotic tissue in photomicrographs of gallocyanin-stained serial sections. After periods of ischemia longer than 40 min, the percentage of necrotic tissue increased linearly with the period of clamping. After 40 min of total ischemia the changes in hepatocytes are for the greater part reversible, whereas after 90 min the majority of the cells have passed the "point of no return" and will no more be able to maintain their integrity.