Abstract: ObjectiveTo investigate the dynamic change of cerebral aquaporin 4 (AQP4) expression level during traumatic brain injury (TBI) in rats and the relationship between AQP4 expression and traumatic brain injury and edema. MethodsThe experimental TBI model was established by bumpiness of free falling body according to Feeney's. The changes of brain water content (BWC) and permeability of blood-brain barrier (BBB) were measured by the methods of wet and dry weight and Evans blue fluorometry. Immunohistochemistry was used to determine the change of expression of AQP4 during different periods after TBI. Results6 h after TBI, water content of brain tissue and EB content in the contusion side significantly increased, and the protein expression of AQP4 in contusion marginal region began to increase. They reached summit 24 h after operation and did not come back normal level 5 d after operation. There was significantly positive correlation between protein expression of AQP4 and change of EB content (r=0.957486,P<0.05). ConclusionThe dynamic change of cerebral AQP4 expression level closely related to the destruction of BBB and the formation of cerebral edema during traumatic brain injury.

Key words: cerebral trauma, cerebral edema, aquaporin 4(AQP4), blood-brain barrier, rat