THE BINDING OF BASIC FIBROBLAST GROWTH-FACTOR TO ISCHEMIC NEURONS IN THE RAT

Transient occlusion of the right middle cerebral artery for 15 min produced a small ischaemic lesion in the dorsal portion of the right striatum in rats as seen on days 3, 7 and 14 postoperatively. The lesions consisted mainly of reactive astrocytes and 'schaemic neurons' with chromatin-condensed (pyknotic) nuclei and homogeneously eosinophilic cytoplasm. The incubation of tissue sections with basic fibroblast growth factor (bFGF) followed by anti-bFGF, or with biotinylated bFGF without anti-bFGF, labelled virtually all ischaemic neurons, indicating that bFGF had bound to the latter. The pretreatment of sections with heparitinase prevented the binding of bFGF to these cells, suggesting that the chemical substrate for the bFGF binding was heparan sulphate. In light of the findings that many normal-looking neurons were observed in the corresponding portion of the right striatum in most rats on post-operative days 28 and 90, the appearance of bFGF-binding sites in ischaemic neurons may contribute to the repair process of injured neurons.