Expression of fibroblast growth factors in rat dorsal root ganglion neurons and regulation after peripheral nerve injury

Using cDNA array, we observed the expression of eight members of the fibroblast growth factor (FGF) family, FGF 2, 5, 7, 9, 10, 13 and 14, in rat lumbar 4 and 5 dorsal root ganglia (DRGs). Over a period of 28 days after sciatic nerve transection, the array signals for FGF 2 and 7 were significantly increased in the DRGs, while FGF 13 decreased. Using the reverse transcription polymerase chain reaction (RT-PCR), we confirmed the axotomy-induced changes in the expression of FGF 7 and 13. In situ hybridization showed that FGF 13 was expressed in 60% of DRG neurons under normal circumstance. Seven days after axotomy the number of FGF 13-positive neurons was decreased to 18%, but partially recovered to 40% after 28 days. FGF 13 immunoreactivity was also decreased. These data indicate that FGFs are important for DRG neurons under normal circumstance and after nerve injury.