THE ANTIOXIDANT ENZYMES GLUTATHIONE-PEROXIDASE AND CATALASE INCREASE FOLLOWING TRAUMATIC BRAIN INJURY IN THE RAT

The inflammatory response following mechanical brain injury is charact erized by an increase in the cytokine interleukin-1 beta (IL-1 beta) f ollowed by a large elevation in the neurotrophin, nerve growth factor (NGF). The substantial upregulation in NGF observed in our previous st udies suggests that it may have functions in addition to that of a tar get-derived neuronal support mechanism. We hypothesize that NGF is a m ediator of oxidative homeostasis, by inducing the production of oxygen -free radical scavengers in brain tissue following injury. We tested t his hypothesis by measuring the activity of the antioxidant enzymes, g lutathione peroxidase (GSH-Px), and catalase in cortical brain tissue following experimentally induced cortical contusion. We observed a two fold increase in GSH-Px and a threefold increase in catalase activitie s in a time course which reflected the temporal increase in NGF observ ed following the same cortical contusion model. These findings support the hypothesis and illuminate an important reparative role for NGF fo llowing trauma. (C) 1997 Academic Press.