Abstract: Objective To investigate the expression changes of aquaporin-1 (AQP1) and aquaporin-9 (AQP9) in rats after traumatic brain injury, and explore the roles of AQP1 and AQP9 in the development of brain edema.Methods In an impact-acceleration head injury model of rat, brain water content was measured by wet-dry weight method at 1 h, 6 h, 24 h, 48 h and 168 h after brain trauma. The expressions of AQP1 and AQP9 in brains were investigated by immunohistochemistry and Western blot.Results Brain water content increased in the injuried brain tissues after 1 h post-injury, reached peak at 24 h and returned at 168 h. Both expressions of AQP1 and AQP9 were induced in reactive astrocytes adjacent to injury sit at 6 h and 24 h after brain trauma. Staining of AQP1 in the endothelial cells was not present in normal rat brains but appeared strong after brain trauma.Conclusion A remarkable induction expression of AQP1 or AQP9 after brain trauma may participate in the development of brain edema.

Key words: traumatic brain injury, brain edema, aquaporin-1, aquaporin-9