Observations on rat spleen reticulum during the development of syngeneic hepatocellular implants.

August rat hepatocytes isolated by collagenase perfusion were implanted directly into the spleens of syngeneic recipients. Graft development was monitored by a combination of staining techniques and when surviving hepatocytes were difficult to recognize by routine histology, indirect immunofluorescence permitted their rapid identification. Liver cells were found up to 21 months after transplantation, thus confirming the ability of the spleen to support hepatocellular grafts. The reticular framework of the spleen appears to play an important role. The reticulum mesh of the red pulp traps injected cells and there is rapid generation of reticulum fibres around them within 4 days. The subsequent proliferation and organization of liver cells into recognizable hepatic plates, glandular rosettes and acini was accompanied by the development of a rich and distinctive reticular scaffold with a pattern resembling that of regenerating splenic tissue.