['Traumatic brain injury (TBI) is a worldwide health problem with oxidative stress recognized as a major pathogenetic factor. The present experimental study was designed to explore the neuroprotective effect of NADPH oxidase (NOX) inhibitor, apocynin, on mouse TBI.', 'Moderately severe weight-drop impact head injury was induced in adult male mice, randomly divided into four groups: sham, TBI, TBI+vehicle and TBI+apocynin treatment. Apocynin (50 mg/kg) was injected intraperitoneally 30 min before TBI. The expression of NOX2 protein was investigated using immunoblotting techniques 1 and 24h after TBI. Neurological score was evaluated 24h after TBI. Blood-brain barrier disruption was detected by Evans blue extravasation and cortical apoptosis was analyzed by TUNEL assay. Additionally, we assessed tissue levels of malondialdehyde (MDA).', 'NOX2 expression increased rapidly following TBI in male mice, with an early peak at 1h, followed by a second peak at 24h. Pre-treatment with the NOX inhibitor, apocynin markedly inhibited NOX2 expression. Apocynin also attenuated MDA levels and TBI-induced blood-brain barrier dysfunction. In addition apocynin significantly attenuated TBI-induced neurological deficits and cortical apoptosis.'] Does nADPH oxidase inhibition improve neurological outcome in experimental traumatic brain injury?