In vivo expression and localization of the fibroblast growth factor systemin the intact and lesioned rat peripheral nerve and spinal ganglia

Basic fibroblast growth factor (FGF-2) is involved in several cellular proc esses of the nervous system during development, maintenance, and regenerati on. In the central nervous system, FGF-2 has been shown to be expressed in neurons and glial cells, depending on the developmental stage and brain are a. In the present study, a comprehensive analysis was performed of the cell ular distribution of the transcripts of FGF-2 and of the FGF high-affinity receptors (R) 1-4 in intact and lesioned sciatic nerve and spinal ganglia. In the adult rat sciatic nerve FCF-2, FGFR1-3 were expressed at low levels as revealed by reverse transcriptase-polymerase chain reaction (RT-PCR). Sc iatic nerve crush resulted in an increase of these transcript levels. FGFR4 expression was not detected in the intact and crushed nerve as revealed by RT-PCR and RNase protection assay. In situ hybridization using riboprobes for FGF-S. FGFR1-3 displayed staining in diverse cell types. Immunocytochem ical staining of consecutive sections with cell markers far myelin, macroph ages, and neurons revealed colocalization of the transcripts with Schwann c ells and macrophages, In addition to FGF-2 and FGFR1, the transcripts of FG FR2-4 were expressed in neurons of spinal ganglia. Crush lesion of the scia tic nerve resulted in no alterations of the FGFR1-4 transcripts, whereas FG F-2 and FGFR3 mRNAs were up-regulated in spinal ganglia. The expression of FGFRs and FGF-S in Schwann cells and macrophages at the lesion site of the sciatic nerve and in sensory neurons suggests that FGF-2 is involved in spe cific functions of these cells during regeneration. (C) 2001 Wiley-Liss, In c.