| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1989: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1988: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Research Abstract |
Using semithin plastic sections, sequential changes in the mouse peritoneal cells and mononuclear cells of extraembryonic coelom during their intrauterine life were observed by light microscopy, and following results were obtained.
1. Peritoneal mononuclear free cells Embryonic peritoneal cavity contained a small number of free mononuclear cells, singly scattered. The cytoplasm contained large phagocytic vacuoles, and long cytoplasmic processes extended from the cell surface. The mononuclear cells could be considered mature macrophages. Most of them were 9 to 12 um in cell diameter, and N-C ratio was smaller than 0.7. In 18-day-old fetuses, the peritoneal cells consisted of mononuclear cells, 79.5%, and mast cells, 20.5%. Small lymphocytes and neutrophils were not contained in embryonic peritoneal cavity.
2. Mononuclear cells in extraembryonic coelom Before 11 days of gestation, the extraembryonic coelom was continuous with the intraembryonic coelom, and the exocoel contained a small number of mononuclear free cells. These cells had an elongated or kidney-shaped nucleus and the cell surface showed many villous projection. The cytoplasm occasionally contained small lucent vesicles but no phagocytic vacuoles. In vitelline vessels at 9 days, mononuclear cells bearing a close morphological resemblance to extraembryonic free cells were observed. It is likely that yolk sac mononuclear cells are the earliest recognizable precursors of mature macrophages in embryonic cavities.
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