Abstract
In the chick and quail embryo, two cell populations migrate into the neural tube from the surrounding mesodermal tissues during the fourth day of incubation: individual cells which represent macrophages, and endothelial cells which remain continuous with the extraneural vessels. We report here on the proliferative capacity of these mesoderm-derived cells. A double-immunofluorescence protocol for two monoclonal antibodies of subtype IgG1, the endothelial cell/macrophage marker QH1, and the S-phase marker bromodeoxyuridine, was developed. With confocal laser scanning microscopy of thick microtome sections, labeling indices of intraneural individual QH1-positive cells (12%) and of endothelial cells (10%) were determined. In contrast, the labeling index of extraneural endothelial cells was 25%. With three-dimensional visualization of confocal data, the variable morphology of macrophages was shown. Our results indicate that: (1) proliferative activity of intraneural capillary endothelial cells is less than expected and that it is absent from sprouts; (2) both spheroidal and ramified macrophages proliferate inside the neural tissues; and (3) ramified macrophages frequently make contact with capillary endothelial cells. We conclude that most embryonic microglia may be derived from the early invasive QH1+ macrophages.
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Accepted: 11 October 1996
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Cossmann, P., Eggli, P., Christ, B. et al. Mesoderm-derived cells proliferate in the embryonic central nervous system: confocal microscopy and three-dimensional visualization. Histochemistry 107, 205–213 (1997). https://doi.org/10.1007/s004180050105
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DOI: https://doi.org/10.1007/s004180050105