Invasion of lymphosarcoma cells into the perfused mouse liver.

Liver of (C57BL X DBA)F1 mice were perfused in situ with a synthetic hemoglobin-free medium, to which murine lymphosarcoma cells were added. All cells were arrested. They were only found in the sinusoids, predominantly in periportal areas. Many lymphosarcoma cells penetrated the walls of the sinusoids with protrusions that extended into and through the endothelial cells. The protrusions often also invaded hepatocytes, and some cells migrated out of the sinusoids. The percentage of the cells that penetrated endothelium was constant and reproducible (68 +/- 4%) in experiments lasting longer than 90 minutes, but the percentage of these cells that also invaded hepatocytes varied greatly. Parellel experiments in vivo yielded similar results, except that the number of cells that invaded hepatocytes was generally much lower. The advantages of the perfused liver as a model for experimental study of the invasion mechanism were evaluated.