In order to evaluate the cellular responses to different treatment modalities following traumatic brain injury, the expression of c-Fos protein and Heat shock protein (HSP70) in rat brain tissue subjected to moderate severity of fluid-percussion injury (FPI) was measured with Western blot analysis.

Male Sprague-Dawley (SD) rats (n=62, 200-250 g) were subjected to sham surgery alone (n=10) or to lateral fluid percussion brain injury of moderate severity (n=52, 2.1-2.5 atm). Parasagittal FPI induced the expression of c-Fos and HSP70 proteins in the hemisphere ipsilateral to the injury. Injured rats were treated with hypothermia (n=20) or decompressive craniectomy (n=20). Ten rats in each group were sacrificed 24h or 72h following FPI. The brain specimens were collected at 24, or 72 hours after injury and prepared for Western blot analysis.

Expression of c-Fos protein and HSP70 following FPI showed a increased pattern at 24 hours post-injury and maintained till 72 hours post-injury. The expression of c-Fos and HSP70 was significantly reduced in rats treated with either moderate hypothermia or decompressive craniectomy at 24 and 72 hours post-injury, compared with those without treatments. The expression patterns of c-Fos and HSP70 were not same, however, theses differences were not statistically significant.

These results suggest that treatment of traumatic brain injury with either decompressive craniectomy or hypothermia may similarly influence the cellular defense mechanism involving the expression of IEGs and HSP70.