Local neutrophil influx following lateral fluid-percussion brain injury inrats is associated with accumulation of complement activation fragments ofthe third component (C3) of the complement system

Traumatic brain injury can lead to locally destructive secondary events med iated by several inflammatory components. Following lateral fluid-percussio n (FP) brain injury in rats, we examined cortical and hippocampal sections for neutrophil infiltration and accumulation of complement component C3. Ne utrophil influx into the brain after injury was detected by an improved mye loperoxidase (MPO) microassay and manual cell counting, while C3 accumulati on was detected using immunocytochemistry. MPO levels were elevated in the injured cortical tissue, whereas C3 immunoreactivity was increased in both injured cortical and ipsilateral hippocampal sections. These results show t hat the FP model of head injury leads to an intense local inflammatory reac tion and subsequent tissue destruction. (C) 2000 Elsevier Science B.V. All rights reserved.