Traumatic injury in vitro induces IEG mRNAs in cultured glial cells, suppressed by co-culture with neurons

GLIAL changes following traumatic injury to glial monolayers as well as to neuronal-glial co-culture systems in vitro were examined with a focus on th e expression of mRNAs coding for the immediate early genes (IEG) c-fos, c-j un and zif/268, demonstrated using in situ hybridization. Glial cells along scratch wound lines extended cytoplasmic processes as early as 10 min post -injury and the whole wound was covered with gliosis by 24 h. For complete restoration in the case of glial cells co-cultured with neurons, this requi red 48h. Induction of the three IEG mRNAs was eminent along the edges of sc ratch wound, peaking at 30-60 min postinjury and subsiding by 3 h. The peak expression of IEG mRNAs was delayed to 1-3h post-injury and became undetec table at 6h in neuronal-glial co-cultures. The data suggest that mechanical injury to glial cells causes gliosis and the expression of IEG mRNAs, whic h are suppressed by co culture with neurons, indicating some influence of n euronal-glial interactions. NeuroReport 10:2439-2448 (C) 1999 Lippincott Wi lliams & Wilkins.