Scanning electronmicroscopic study of the red pulp of mouse spleen

Tn order to study three-dimensional fine architecture of the red pulp, especially the relationships between the splenic sinuses and the cordal capillaries, mouse spleens were perfusion-fixed, loading normal arterial and venous hydrostatic pressures via the abdominal aorta and the portal vein. The fixed splenic tissue were alcohol-freeze-fractured and specimens were processed routinely for scanning electron microscopy (SEM). The normal red pulp of the mouse spleen consists, like spleens of many other mammals, of the splenic cords formed by a three-dimensional network of reticular tissue and of the splenic sinuses separated by areas of the splenic cords. The inner surface of the sinus wall is covered with a lining of irregularly shaped flat cells with scattered nuclear protuberances. The outer surface of the sinus wall is covered with attenuated reticular cell processes supporting the sinus. The wall of the splenic sinus is perforated with round or elliptical stomata 1 to 3 /im in di-ameter through which the sinus lumen communicates with the cordal laby-rinthine space. In comparison with other mammals such as human, dog an