Protective effect of different concentrations of normobaric oxygen in early cerebral ischemic-reper-fusion injury rat model

Objective To observe the protective effect of different concentrations of normobaric oxygen (NBO) on rats with acute cerebral ischemia reperfusion in early time.Methods 120 rats were divided randomly into high,medium and low NBO treatment groups and model group.Every group was divided into 3,6,12,24,48,and 72 h subgroups after ischemia reperfusion (n =5 each).The neurologic impairment scores were assessed in rats before and after oxygen inhalation,and the expression of Caspase-9 and Caspase-3 protein was detecte 4 d by using immunohistochemistry.Results Neurologic impairment scores in NBO treatment groups were decreased to varyoing degrees.There was statistically significant difference beween the high NBO treatment group (1.40 ±0.55,1.20 ±0.45,1.40 ±0.55,1.20 ±0.84,1.20 ±0.84,1.00±0.71) and the model group (2.20 ±0.45,2.20 ±0.84,2.20 ±0.45,2.20 ±0.45,2.80 ±0.84,2.60 ± 0.54) at each time point (P ＜ 0.05).The expression of Caspase-9 and Caspase-3 protein in the high,medium and low NBO treatment groups was lower than in the model group (P ＜ 0.05) at each time point.Conclusion The high concentration of NBO could reduce the expression of Caspase-9 and Caspase-3 protein obviously in rats with acute cerebral ischemia reperfusion and enhance the neurological function in early time,and medium and low concentrations of NBO had obvious effect delay as compared with high concentration of NBO. Key words: Normobaric oxygen;  Cerebral ischemia;  Reperfusion injury;  Caspase-9 ; Caspase-3