An electron microscopic study of phagocytic ability of epithelial cells in mollar tooth germ of mouse embryos

Abstract

The epithelial tooth germs of mandibular first molars of mice from the 17th day of gestation to birth were investigated by electron and light microscopy. The following results were obtained: 1) On the 17th day of gestation, blood vessels were close to the external epithelium. Free red blood cells which seemed to come through these blood vessels were scattered among the stellate cells. 2) These blood vessels were considered to some variation of sinusoidal capillaries. 3) On the 18th day, the blood vessels penetrated into the stellate reticulum at the transitional portion between the dendal lamina and the epithelial tooth germ. The basal lamina of the external epithelium and that of the blood vessels at the site of invasion were discontinuous and not distinguishable. 4) Two types of cells which phagocytosed the free blood cells were observed in the stellate reticulum; one was macrophages and the other was stellate cells. The epithelial cells of developing tooth germs, in particular seemed to have the phagocytic ability.