Electron microscopic study on the migrating process of supraependymal macrophages in the third ventricle of rat

Different phases of migrating supraependymal macrophages in the third ventricle of rat were observed by scanning electron microscopy(SEM).The cell type of supraependymal macrophages and its relevant functions were analysed using transmission electron microscopy(TEM).The results indicated that the cell bodies of supraependymal macrophages in the third ventricle were ovoid or elliptic in shape and stretched out several peripheral lingual and fingerlike pseudopods.The whole migrating process may be,at first,a dome-like structure was formed on the surface of ependyma,then the interspace between ependymal cells were pushed open and the cell body of the migrating macrophages appeared,and eventually moved outside and droped in the ventricular lumen.Under TEM,supraependymal macrophages were ovoid with a large nucleus and scant of cytoplasmic organelles.These morphological characters are compatible with the characteristics of mononuclear phagocytes and provide the ultrastructural basis for further research on their functions.