Brain injury induces c-fos protein(s) in nerve and glial-like cells in adult mammalian brain.

Recent studies have shown that the c-fos protein(s) exists in low basal levels in adult mammalian neurons, but not in glial cells. Here we report that c-fos-protein-like immunoreactivity is induced in glial cells following cortical injury. Glial cells in white matter regions around the wound margin express the c-fos protein maximally at 12-24 h post-insult. Injury is also associated with a massive induction of c-fos proteins in nerve cells in the damaged cerebral cortex. Injections of [3H]thymidine into mice and autoradiographic analysis of [3H]thymidine incorporation showed that the increase in c-fos preceded glial cell division following injury. These results show that c-fos protein is induced in glial and nerve cells after injury.