[Expression of Aquaporin 4 in Diffuse Brain Injury of Rats]

To observe the expression of aquaporin 4 (AQP4) in diffuse brain injury (DBI) of rats and to explore the corresponding effect of AQP4 for brain edema.The rat model of DBI was established using Marmarou's impact-compression trauma model. Brain water content was measured by dry-wet weight method. Blood-brain barrier permeability was evaluated by Evans blue (EB) staining. Immunohistochemical method was used to observe the expression of AQP4.Brain water content increased after 3 h and peaked at 24 h after DBI. Brain EB content significantly increased and peaked at 12 h after DBI. The expression of AQP4 significantly increased after 3 h and peaked at 24 h after DBI, and the number of AQP4 positive astrocytes increased.The increment of the permeability of blood-brain barrier and the expression of AQP4 may contribute to the development of brain edema in rat DBI. The change of AQP4 expression in astrocytes may also contribute to determine DBI.