Electron microscopic study of the spleen of the hedgehog (Erinaceus europaeus) . I. Cells of the reticulum, venous sinuses and erythropoietic foci
Cirri-Borghi, M.B.
Bollettino della Societa Italiana di Biologia Sperimentale 50(1-2): 6-9
1974
ISSN/ISBN: 0037-8771 PMID: 4425588 Document Number: 75160
The spleen of the hedgehog [E. europaeus] has few sinus formations, a considerable development of pericapillary sleeves and a large number of giant elements very similar to those of the bone marrow. During hibernation the volume increases due to an accumulation of blood in the venous sinuses and the red pulp. When the hibernating animal is exposed to a temperature of 35.degree. C for 6 h the structure returns to the waking state; there is a gradual return, characterized by blood depletion, mobilization of lymphocytes in the white pulp and reappearance of blood platelet formation. These phenomena were further studied ultrastructurally, with particular reference to the venous sinuses and the erythropoietic foci. Spleen fragments of 5 adult hedgehogs in the waking state, 2 in hibernation for 10 days at +9.degree. C and 49 days at +8 and +5.degree. C and 2 waking animals at +17.degree. and +33.degree. C, were fixed, sectioned and stained. In the waking state the reticular cells were characterized by irregular shape with well developed granular endoplasmic reticulum or numerous ribosomes, free or grouped in polysomal complexes, a somewhat reduced Golgi zone and many small mitochondria. In hibernation the cells of the reticulum appeared to be dissociated due to the accumulation of erythrocytes in the red pulp.