The concerns about negative consequences of estrogen therapy have led to introduce other strategies to obtain estrogen's benefits in the brain. The present study tests the hypothesis that a major isoflavone of soy; genistein with estrogen-like activity can be neuroprotective in traumatic brain injury (TBI). The male Wistar rats were randomly divided to four groups: sham, TBI, vehicle and genistein. The TBI was induced by Marmarou method. The brain edema and the disruption of blood–brain-barrier (BBB) were evaluated 48 h post-TBI. Genistein (15 mg/kg) or dimethyl sulfoxide (DMSO) was injected i.p., twice after TBI. The intracranial pressure (ICP), the motor performance, and the beam-walk task (WB) were determined before trauma, on trauma day (D0), and first (D1) and second (D2) days post-TBI. Genistein inhibited a development of brain edema and a BBB permeability in TBI animals. An increase of ICP and a …