Migration and Proliferation of Motile Immature Glial Cells in the Developing Cerebral Cortex of Infantile Rat

Abstract

Using immunohistochemistry of thymosin β4 (Tβ4), GFAP, vimentin 9 and lectin histochemistry of Griffonia simplicifolia B4 isolectin (IB4), we investigated migration and proliferation of immature glial cells in the infantile rat cerebral cortex from P0 to P60. Although the immature glial cells in the cortex are commonly Tβ4 positive, dynamic behavior of the immature glial cells are dramatically different before and after P11; between P0 and P11, they are actively migrating, highly proliferative and differentiate other types of glial cells, while after 12 days of birth, they turn out to react positively with Thiamine pyrophosphatase (TTPase), a definitive marker of mature microglia, and stop migration and proliferation. We concluded that the Tβ4 positive immature glial cells in the rat cortex before P11, although they have been called the microglia, are glioblasts, common precursors of neuroglia, and they are differentiated into microglia during the second postnatal week.