Temporal profile of cerebrospinal fluid glutamate, interleukin-6, and tumor necrosis factor-alpha in relation to brain edema and contusion following controlled cortical impact injury in rats

Traumatic brain injury is associated with release of the excitotoxin glutam ate and production of pro-inflammatory cytokines IL-6 and tumor necrosis fa ctor-alpha (TNF-alpha). Following controlled cortical impact injury, cerebr ospinal fluid (CSF) glutamate, IL-6, and TNF-alpha concentrations were meas ured to investigate their relationship to evolving tissue damage. Compared to non-traumatized rats CSF glutamate, IL-6 and TNF-alpha: levels were sign ificantly increased by 8 h after trauma (P < 0.005). Parallel to Increasing brain swelling and contusion CSF glutamate was significantly elevated over time, reaching highest levels by 48 h (33 +/- 4 mu M) while IL-6 and TNF-a lpha showed maximum values at 24 h after trauma (42 +/- 7 and 4.7 +/- 1 pg/ ml) (P < 0.005). The observed different temporal profile of CSF glutamate, IL-6, and TNF-alpha following focal traumatic brain injury could be of ther apeutic importance. (C) 2000 Elsevier Science Ireland Ltd. All rights reser ved.