REACTIVE ASTROCYTES EXPRESS THE EMBRYONIC INTERMEDIATE NEUROFILAMENT NESTIN

NESTIN is a neurofilament protein expressed by the immediate precursor s to neurons and glia in rats and humans. Nestin immunoreactivity in t he rat CNS was studied following kainic acid (KA) hippocampal lesions. Numerous nestin positive cells within the KA lesion were confirmed to be reactive astrocytes by their immunoreactivity for glial fibrillary acidic protein (GFAP). The number of these cells decreased with time after the KA lesion and no astrocyte immunostaining for nestin was obs erved in control animals. A subset of nestin-positive cells in the ven tricular subependymal region appeared to be radial glial cells, extend ing to cell body layers. Nestin is one of several embryonic markers ex pressed by reactive astrocytes, suggesting an embryonic reversion indu ced by the KA lesion, possibly to enhance functional recovery.