Abstract: Objective To investigate the expression of aquaporin 9(AQP9) and its influence after chronic cerebral ischemia. Methods rats were randomly divided into sham operation group and chronic cerebral ischemia 1, 3 and 6 months groups. Ligation of bilateral common carotid artery (2-vo) was induced to build chronic cerebral ischemia model. The animals were sacrificed after chronic cerebral ischemia. The ability of learning and memory of rats was measured by morris water maze test. Brain water content (BWC) was measured by the wet-dry weighing ratio method. HE staining was used to observe the morphological changes after cerebral ischemia. to detect the contents of lactic acid in brain by absorption spectrophotometry. Immunofluorescence and Western blotting were used to test the expression of AQP9 in brain. Results Compared with the sham operation group, the ability of learning and memory of rats in all chronic cerebral ischemia groups decreased distinctly. Brain water content did not changed significantly in all the groups of chronic cerebral ischemia (P > 0. 05). Proliferation of glial cells and neurons apoptosis were observed in all chronic cerebral ischemia groups detected by HE staining. The contents of lactic acid in brain was increased in all chronic cerebral ischemia groups (P < 0. 05). The expression of AQP9 was increased in all chronic cerebral ischemia groups detected both in immunofluorescence and Western blotting (P < 0. 05). Conclusions The expression of AQP9 was increased after chronic cerebral ischemia, which may participate in transport of energy substrate after ischemia.

Key words: Chronic ischemia, brain, aquaporin-9