Objective   To study the effects of chronic intermittent hypoxia and removal of hypoxia on learning and memory ability and glial fibrillary acidic protein (GFAP) expression in CA3 region of hippocampus in Sprague-Dawley rats.     Methods   A total of 24 Sprague-Dawley rats were randomly assigned to three experimental groups: unhandled control group (UC)

chronic intermittent hypoxia group (CIH)

and removal of hypoxia group (RH). Rats in CIH group and RH group underwent intermittent hypoxia for 8 h everyday. The duration of experiment was 4 weeks

and then those in RH group were fed normally in 4 more weeks. The learning and memory ability of rats in each group was assessed with the Morris water maze test. GFAP expression in CA3 region of hippocampus was also investigated.     Results   ① Morris water maze test learning scores: CIH groupRH groupUC group (P0.01

P0.05); ② Morris water maze test memory scores: The number of times of crossing the platform and the percentage of time spent on crossing the target quadrant to the total swimming time: UC groupRH groupCIH group (P0.01

P0.05); ③ GFAP expression in CA3 region of hippocampus: CIH groupRH groupUC group (P0.01).    Conclusion   Chronic intermittent hypoxia can attenuate the function of learning and memory in rats

but the function of learning and memory can be partly improved after removal of hypoxia

suggesting that the attenuated learning and memory in rats may be associated with the changes in GFAP expression in CA3 region of hippocampus in rats.