Changes in the Microglial Population during Spinal Cord Formation Indicate an Involvement of Microglia in the Regulation of Neuronogenesis and Synaptogenesis.

The localization and distribution of microgliocytes in the spinal cord (SC) of rat embryos during the formation of motor neuron precursors were studied. Antibodies to the Iba1 protein were used for the identification of microglial cells. To study the dynamics of the development of embryonic SC cells, we used the following immunohistochemical markers: vimentin (a marker of radial glia cells), doublecortin (a marker of neuroblasts), and synaptophysin (a marker of synaptic vesicles). It is shown that microglia progenitors penetrate the dorsal part of the spinal cord on day 12 of embryonic development; they are detected in the area of emerging motor neurons on day 14. It was found that embryonic microgliocytes are in close relationship with the processes of the radial glia and the processes of the neuroblasts of the anterior horns. The study into the dynamics of the development of the rat embryonic SC and the comparison of the processes of its histogenesis with the localization and morphological changes of the embryonic microglia indicates its participation in synaptogenesis and the differentiation of motor neurons (neuronogenesis). [ABSTRACT FROM AUTHOR]