Temporal variability of jun family transcription factor levels in peripherally or centrally transected adult rat dorsal root ganglia.
Enhanced chemiluminescent (ECL) immunoblotting was used to quantitatively assess the initial changes in jun family transcription factor protein levels in adult rat lumbar dorsal root ganglia (DRG) after peripheral axotomy and dorsal root transection, and to study the effects of neurotrophic factor administration on these changes. Transection of central (dorsal root) or peripheral (spinal nerve) branches of DRG neurons resulted in rapid elevation of c-jun protein levels, which was transient after dorsal root transection but sustained, though slightly attenuated, after spinal nerve transection. These results suggest that injury-induced c-jun elevation is biphasic, consisting of an early, transient, injury-initiated phase and a more prolonged secondary phase specific to peripheral target disconnection. c-jun protein changes were not modulated by administration of NGF or BDNF. Immunohistochemistry was used to localize c-jun protein induction to DRG neurons. Using ECL immunoblotting, we also observed temporally regulated increases in junD protein levels after both injuries. A transient up-regulation of junB was detected by immunoblotting 5 days after peripheral axotomy, coincident with a slight decrease in c-jun protein levels.