Study of the haemopoietic tissues during the pre-and post-natal life of the mouse

Abstract

In the present study, Swiss mice strain was used, a total number of

25 embryos and another 25 mice at different ages postnatally were used. The embryonic ages were 12,13,16,17, 18 days of gestation while mice used postnatally were at 0 day(the day ofbirth), 3,5,10 and at 21 days old. The pregnant and postnatal mice at the selected ages, were injected slowly with 0.3 ml aqueous buffered solution containing carbon particles, tow hours before sacrifice. This was to determine tlie phagocytic uptake of the carbon particles by the macrophages. Mice were anaesthetized using ether then livers, spleens, and bone marrows were aspirated under aseptic conditions and the aspirate was spread, air dried and stained by Leishman stain. Tissue pieces from livers, spleens and bone marrows were obtained, fixed and processed by paraffin technique then stained by hematoxylin and eosin. Some of these tissues which processed by the paraffin technique were deparaffinized and treated with Perls' Prussian blue reaction, to detect ferrous and ferric iron in the haemopoietic foci. The light microscopic study and morphological analysis were done revealing that: In fetal liver, at 12 days of gestation, the haemopoietic cells appeared obviously, there were numerous proerythroblasts and few basophilic erythroblasts. At 12-13 days of gestation, the number of haemopoietic cells with clear-cut erythrocytic features had increased. The morphologic differentiation of erythroid elements within the fetal mouse liver proceeds through a series of stages, denoted as proerythroblasts, basophilic, polychromatophilic, orthochromatic erythroblasts, reticulocytes, and mature erythrocytes. During the maturation of the hepatocytes, the haemopoietic cells were gradually incorporated within