EXPRESSION OF MONOCYTE CHEMOATTRACTANT PROTEIN (MCP-1) AND NITRIC-OXIDE SYNTHASE-2 FOLLOWING CEREBRAL TRAUMA

Traumatic injury to the brain initiates multiple interrelated processe s that involve parenchymal, vascular, and infiltrating inflammatory ce lls. Nitric oxide (NO) and chemokines have been implicated as regulato rs of the central nervous system ir?jury response, Following a cryogen ic lesion of the cerebral cortex in mice, mRNA for NO synthase (NOS)-2 was detected by reverse transcriptase polymerase chain reaction ipsil aterally 12 h after injury and persisted for 2 weeks. While mRNA was a lso detected contralaterally, the time course of expression was shorte r (1 week). By immunohistochemistry, NOS-2 protein was initially detec ted ipsilaterally 12 h after injury in infiltrating inflammatory cells . Astroglial cells expressed NOS-2 from 24 to 72 h after injury. The e xpression of monocyte chemoattractant protein (MCP-1) mRNA peaked at 6 h on the lesion side, remained for 24 h and then declined by 48 h. On the unlesioned side, MCP-1 mRNA was expressed to a much lesser extent and had declined by 24 h. The up-regulation of MCP-1 was relatively s pecific as a closely related mRNA encoding IP-10 was not significantly increased. These findings implicate a role for NOS-2 and MCP-I as pot ential regulators of cellular events following cryogenic cerebral trau ma.