Effect of intermittent normobaric hyperoxia on bloodbrain barrier in a rat model of stroke

Recent studies have shown that the use of prolonged or intermittent normobaric hyperoxia (90 percent) can decrease brain damages caused by stroke. The aim of this study was to investigate the effects of oxygen radicals in potentiating the blood-brain barrier caused by normobaric hyperoxia in a rat model of stroke. This was a experimental study performed in spring 2010. A total of 42 male Wistar rats (250-350 g) were initially divided into two main groups. Both group were exposed to normobaric hyperoxia (90 percent; HO) and room air (21 percent; RA) 4 h/day for 6 days. Later، each main group was subdivided into three subgroups to receive dimethyltiourea. After 24 h، the neurologic deficit scores and blood-brain barrier permeability were assessed. Data were analyzed by one way ANOVA and Mann Whitney U tests. The medians of neurologic deficit scores and blood-brain barrier permeability decreased in RA and HO (P=0. 02). The neurologic deficit score and the reduced brain edema were significantly relived by MT (P=0. 43). The blood-brain impermeability caused by intermittent normobaric hyperoxia was relieved by use of oxygen radical scavengers.