DIFFERENTIAL UPTAKE OF DEXTRAN BEADS BY ASTROCYTES, MACROPHAGES AND OLIGODENDROCYTES IN MIXED GLIAL-CELL CULTURES FROM BRAINS OF NEONATAL RATS

The present study addresses a controversy over the abilities of astroc ytes to perform phagocytosis. Primary glial-cell cultures were prepare d from the brains of neonatal rats and were incubated with fluorescent ly-labeled dextran beads (molecular weights similar to 10 and similar to 40 kDa). Astrocytes and oligodendrocytes were double-labeled by imm unofluorescence staining of cell-specific markers, and microglia by le ctin histochemistry. Cells were permitted to take up beads for 1 h, fi xed, and incubated with primary antibodies, followed by fluorescent se condary antibodies or fluorescently-labeled lectin. Macrophages and as trocytes internalized beads of both sizes. In astrocyte processes the beads appeared to line up along glial filaments. The results, which pr ovide direct evidence for uptake of beads by astrocytes in vitro and a gainst equally rapid, if any, uptake by oligodendrocytes, bear upon is sues of acid/base balance and glial cell development and are relevant to neuropathological observations in human disease. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.