Increased expression and nuclear accumulation of basic fibroblast growth factor in primary cultured astrocytes following ischemic-like insults.

Basic fibroblast growth factor (bFGF) is a biological active polypeptide with potent trophic effects on neurons, glia and endothelial cells. In the present study, we examined the temporal expression profile of bFGF protein in cultured cortical astrocytes under ischemic-like conditions such as serum-free, glucose-free or glutamate application. A peak increase of bFGF level was observed at 24 h after the initiation of insults. A striking increase in the bFGF immunoreactivity and a moderate increase in the fibroblast growth factor receptor-1 (FGFR-1) immunoreactivity were also found in the astrocytes treated with serum- or glucose-deprivation or glutamate. The increased bFGF immunoreactivity and FGFR-1 immunoreactivity were mainly accumulated in the nuclei of astrocytes. The results suggest that the expression of bFGF and FGFR-1 in the astrocytes, especially in the nuclear interior, can be up-regulated under ischemic-like conditions and that the up-regulation of bFGF and FGFR-1 may play an important role in the maintenance and repair of the central nervous system (CNS) after ischemia.