Abstract: Objective To investigate observe the effects of asphyxial hypoxic preconditioning on neurological symptoms,expression of Hypoxia-inducible factor-1α(HIF-1α),content of nitric oxide(NO) and nitric oxide synthase(NOS) in brain tissue after intracranial hemorrhage(ICH) in rats.Methods 180 male SD rats were randomly allocated into three groups: sham group(group S,n=60),ICH group(group I,n=60) and preconditioning group(group P,n=60).The rats were anesthetized,paralyzed with vecuronium 2 mg/kg and mechanically ventilated.The rats in P group were pretreated with four times of preconditioning,by being stopped ventilation for 1 min and reventilated for 5 min per circle.One hour later,endotracheal was extubated. ICH model was made by stereotactic injection of 50 μL antilogous blood into the caudate nucleus in group P and I,and 50 μL saline in group S.Neural deficit scores(NDS) and Rosenberg scores were evaluated and the expression of HIF-1α in cerebral tissues were detected by using immunohistochemistry techniques and the content of NO and NOS were assayed by spectrometry at 6 h,(24) h,48 h and 72 h after intracerebral hemorrhage.Results In group P,NDS scores were much better at 6 h,24 h and 48 h than that in group I(P<0.05).Rosenberg score was significantly decreased in group P at 6 h(3.9±1.5) as compared with group I(5.4±1.5,(P<)0.01).HIF-1α expression raised obviously at 24 h and increased to the 72 h after ICH.The number of HIF-1α positive cells was much higher in group I than that in group P at 24 h and 48 h after ICH(P<0.01).Compared with the S group,NO and NOS content in group P and I raised obviously after 6 h ICH.But in group P the changes of NO and NOS content were much less at(24) h than that in group I((P<)(0.01)).Conclusion Asphyxial hypoxic preconditioning improves NDS and Rosenberg scores and demonstrates cerebral protective effect after ICH in rats which maybe related to the decreasing of the HIF-1α expression and the depressing of the NO and NOS increase in brain tissue.

Key words: hypoxic preconditioning, intracerebral hemorrhage, NDS scores, HIF-1α, NO, NOS scores