[Expression of aquaporin-4 protein in rats with acute radiation-induced cerebral edema].

OBJECTIVE: To explore the relation between changes in expression of aquaporin-4(AQP4) protein and acute radiation-induced cerebral edema after Gamma knife radiation. METHODS: The experimental model was established in rats by radiating 2 mm right to median line in cerebral hemisphere with 50 Gy Gamma knife (the center located at the line of auditory canal). The changes of brain water content were measured by the wet and dry weight method. Immunohistochemistry was used to determine the change of expression of AQP4 protein at different periods after Gamma knife radiation. RESULTS: The brain water content and the expression of AQP4 in the target area and the peripheral zone obviously increased at 12 h after Gamma knife radiation, and achieved the peak after 2 d. It was still higher than normal after 14 d. The gray value of expression of aquaporin-4 was negatively related to brain water content (r=-0.9857, P<0.05). CONCLUSION: AQP4 has a close relationship with acute radiation-induced cerebral edema.