the role of oxygen radicals-scavenger in neuroprotection-induced by normobaric hyperoxia on infarct volume in the rat brain

objective: recent studies have shown that the use of prolonged and intermittent normobaric hyperoxia (95%) decrease the infarct volume of stroke. the aim of current study was to study the effect of an oxygen radicals-scavenger applied during intermittent normobaric hyperoxia on infarct volume in the rat brain and neurologic deficit. materials and methods: male wistar rats (250-350 g) were divided to two main groups. these groups were respectively subjected to room air (21% o2; ra) or normobaric hyperoxia (95% o2; ho) 4 hours per day for 6 days. each main group was divided to three subgroups which received nothing (ra and ho), normal saline (ho-s and ra-s) or dimethyltiourea (ho-mt and ra-mt. afterward, all rats were subjected to 60 min middle cerebral artery occlusion (mcao). after 24 h, neurologic deficit scores and infarct volume were assessed. results: the medians of neurologic deficit scores in ra, ra-mt, ra-s, ho-mt, ho-s, and ho were 2, 2, 2, 2, 0, 0, respectively. the infarct volume in ra, ra-mt, ra-s, and ho-mt versus ho-s, and ho were increased. above results showed that neurologic deficit score and infarct volume were restored by mt significantly. conclusion: the effective neuroprotection induced by intermittent normobaric hyperoxia seems to be mediated at least partially by oxygen radicals.