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

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. 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. 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. The effective neuroprotection induced by intermittent normobaric hyperoxia seems to be mediated at least partially by oxygen radicals.