Ultrastructural aspects of red cell destruction in the normal rat spleen

Abstract

Pulp from normal rat spleens was studied with the light and electron microscopes. Macrophages in the red pulp, marginal zones, and peripheral white pulp were involved in the phagocytosis of red cells and to a lesser degree of platelets and leukocytes. The endothelial cells lining sinuses did not take part. No intravascular lysis or extracellular fragmentation of red cells was observed, and no morphological evidence of extracellular degeneration of red cells was obtained. A peculiar type of degradation of the phagocytosed erythrocyte was observed. Soon after the cell had been phagocytosed, a peculiar “tunnelization” or canalization occurred.