INTRALESION INJECTION OF BASIC FIBROBLAST GROWTH-FACTOR ALTERS GLIAL REACTIVITY TO NEURAL TRAUMA

A traumatic injury to the rat brain is known to induce astrocyte proli feration and hypertrophy leading to astrogliosis. In addition, trauma also induces microglial proliferation in the brain. Since basic fibrob last growth factor (bFGF) is believed to play a role in mediating glia l responses to brain injury, we examined the effects of bFGF administr ation on astrocyte and microglial proliferation and astrocyte hypertro phy resulting from a traumatic injury to the rat brain. Intracerebrove ntricular infusion of bFGF for 2 days prior to and following injury fa iled to alter glial reactivity. In contrast, a single intralesion inje ction of bFGF immediately after injury increased total cell. division 2 and 5 days later, with an exclusive effect on glial fibrillary acidi c protein-negative glia which consisted mostly of cells of macrophage- microglial phenotype. In addition, bFGF also enhanced injury-induced a strocyte hypertrophy. These results support a role for bFGF in macroph age-microglia proliferation and astrocyte hypertrophy following brain injury. They also suggest that alteration of injury responses of nonne uronal cells of the brain may be a potential side effect of intracereb ral administration of bFGF. (C) 1994 Academic Press, Inc.