关键词: 脑水肿; 水通道蛋白质4; 甘露醇

Abstract: Objective To study the aquaporin-4(AQP-4) expression after cerebral ischemia and the effect of mannitol on AQP-4.Methods The middle cerebral artery thrombosis model were established , randomly divided into three groups, low dose mannitol group (0.5g/kg, n=32), high dose mannitol group(1.0g/kg,n=32)and control group (n=32), and 5 rats were randomly decapitated at the time points of 6h, 12h,1d and 3d after cerebral ischemia (n=5 in each group). Meanwhile, we also establish sham group(n=5). Brain tissues were taken, the brain water content and permeability of Blood-brain Barrier were detected (Evans blue as a tracer), reverse transcription-polyrnerase chain reaction (RT-PCR) were used to detect the expression of AQP-4.Results In low dose group, high dose group and control group, brain water content in ischemic tissues increases after cerebral ischemia, and reaches 3d as the highest point (P <0.05), no significant differences is observed among groups(P >0.05); In low dose group , high dose group and control group, the Evans Blue in ischemic tissues increases after cerebral ischemia, and reaches 1d as the highest point (P <0.05), no significant differences between groups(P >0.05); In control group, the expression of AQP-4 mRNA in peri-ischemic cortex reaches 1d as the highest point, then declines at 3d, but still at high level(P <0.05); and there is a significant difference with low dose groupand high dose group (P <0.05), no significant differences between low dose group and high dose group(P >0.05).Conclusion The dynamic change regulation of expression of AQP-4 mRNA in rat peri-ischemic cortex after cerebral ischemia suggest that AQP-4 is closely related to the occurrence and development of cerebral edema; mannitol can significantly reduces the expression of AQP-4 mRNA in peri-ischemic cortex, and that mannitol is a disincentive for AQP-4.

Key words: Brain edema; Aquaporin-4; Mannitol