J. Neurochem. (2010) 115, 921–929. Abstract Antagonism of tumor necrosis factor‐alpha with etanercept has proved to be effective in the treatment of spinal cord injury and centrally endotoxin‐induced brain injury. However, etanercept may offer promise as therapy for traumatic brain injury (TBI). In this study, anesthetized rats, immediately after the onset of TBI, were divided into two major groups and given the vehicle solution (1 mL/kg of body weight) or etanercept (5 mg/kg of body weight) intraperitoneally once per 12 h for consecutive 3 days. Etanercept caused attenuation of TBI‐induced cerebral ischemia (e.g., increased cellular levels of glutamate and lactate‐to‐pyruvate ratio), damage (e.g., increased cellular levels of glycerol) and contusion and motor and cognitive function deficits. TBI‐induced neuronal apoptosis (e.g., increased numbers of terminal deoxynucleotidyl transferase αUTP nick‐end labeling and neuronal‐specific nuclear protein double‐positive cells), glial apoptosis (e.g., increased numbers of terminal deoxynucleotidyl transferase αUTP nick‐end labeling and glial fibrillary acidic protein double‐positive cells), astrocytic (e.g., increased numbers of glial fibrillary acidic protein positive cells) and microglial (e.g., increased numbers of ionized calcium‐binding adapter molecule 1‐positive cells) activation and activated inflammation (e.g., increased levels of tumor necrosis factor‐alpha, interleukin‐1β and interleukin‐6) were all significantly reduced by etanercept treatment. These findings suggest that etanercept may improve outcomes of TBI by penetrating into the cerebrospinal fluid in rats.

Collectively, these results suggest that HBO2 therapy may improve outcomes of TBI in rats by inhibiting activated inflammation and gliosis while stimulating both angiogenesis and neurogenesis in the early stage.