Neuroglial response to sciatic neurectomy. II. Electron microscopy,

The response of oligodendrocytes, astrocytes, multipotential glia (MPG), and pericytes to sciatic neurectomy in young adult rats was studied by electron microscopy. Animals were perfused with aldehyde fixative at 2, 4, 7, and 14 days postoperative (dpo). Neuronal changes were slight and there was no apparent response in either oligodendrocytes or pericytes. Typical reactive changes observed in the astrocytes included an increase in glial filament bundles and microtubles. At 2 dpo mitotic cells were observed and by 4 dpo many MPG were located around affected neuron cell bodies apparently isolating them. The MPG processes formed overlapping sheets of processes between neurons and the elements of the neuropil. Hence synaptic boutons were displaced from the surfaces of the ensheathed neurons, but phagocytosis of synaptic boutons was rarely observed. The role and origin of the MPG and their similarity to microglia are discussed.