Cortical basic fibroblast factor expression after head injury: preliminary results

Growth factors are important for normal development and maturation of the CNS. Recently, interest has centred on the role of these factors in response to the CNS injury. Basic Fibroblast Growth Factor (bFGF) stimulates mitogenesis of neuroectodermal tissues, potentially promoting neuronal survival and astrocytic growth suggesting a possible role following injury. We have studied expression of bFGF in male Sprague-Dawley rats subjected to a fluid percussion head injury of 4 atmospheres. Sham operated controls and injured animals were perfused 48 h after injury. 50 micron frozen sections of fixed tissue were immunohistochemically analysed for bFGF expression using the avidin-biotin complex technique with antibodies to bFGF. In the cortex, bFGF expression on astrocytes was enhanced in the injured hemisphere as compared with the contralateral uninjured hemisphere or controls (914 vs. 334 cells/mm2). bFGF expression in the hippocampal (CA2) neurons was the same for both normal and injured rats. The finding of enhanced bFGF in the cortex is consistent with the pathologic astrocytic responses found 48 h after injury and may correlate with later gliosis. These results suggest further study of bFGF, its temporal expression and relationship to other growth factors is warranted.