Effects of propofol on the expression AQP-4 in rat brains following ischemia-reperfusion injury

Objective Propofol has a cerebral protective effect,but its molecular mechanism remains unclear.Aquaporin 4(AQP-4) is related with brain edema following brain injury.The aim of this research was to explore the expression of AQP-4 in rat brains following ischemia-reperfusion injury and the effect of propofol on it.Methods A total of 108 male adult SD rats weighing(220 ± 20) g were randomly allotted to three groups of 36 each: sham-operation,ischemia-reperfusion injury(IR) and propofol.The latter two groups were given normal saline at 2 ml/(kg·h) and propofol at 20 mg/(kg·h) respectively,starting from 20 min before ischemia until 3 hours after ischemia-reperfusion injury.The rats were sacrificed at 0.5,1,3,6,12 and 24 h after reperfusion respectively,6 each time.The water contents of the brains were measured,and the expressions of AQP-4 mRNA and AQP-4 protein in the brains of the rats were detected by RT-PCR and Western-blot.Results The brain water content began to increase at 3 h after reperfusion,but it was significantly lower in the propofol than in the IR group at 3,6,12 and 24 h(P 0.05 or 0.01).Both the expression of AQP-4 mRNA and that of AQP-4 protein were significantly increased after ischemia-reperfusion injury(P0.05 or 0.01),the former peaked at 12 h,and the latter at 6 h.Compared with the IR group,the propofol group showed significantly decreased expressions of AQP-4 mRNA and AQP-4 protein at different time points after ischemia-reperfusion injury(P 0.05 or 0.01).Conclusion Propofol can partially suppress the expressions of AQP-4 mRNA and AQP-4 protein and antagonize the increase of water content in rat brains following ischemia-reperfusion injury,which may be one of the mechanisms of its neuroprotection.