大鼠颅脑损伤急性期水通道蛋白4表达变化的研究

Expression of AQP4 during acute stage of traumatic brain injury in rats

目的探讨水通道蛋白4(AQP4)在大鼠重型颅脑损伤时的表达变化及其与脑水肿间的关系。方法98只成年雄性Wistar大鼠,随机分为对照组及实验组(伤后0.5、2、6、12、24、48、72 h共7组,对照组不打击)。制作大鼠液压冲击颅脑损伤模型,分别于伤后0.5、2、6、12、24、48、72 h采用干湿比重法测脑组织含水量,半定量反转录聚合酶链反应(RT-PCR)检测脑组织AQP4 mRNA表达及其变化。结果脑组织AQP4 mRNA在伤后0.5 h开始表达上调,2、6、12 h依次增高,24 h达到峰值(P<0.05),72 h时仍维持较高水平。脑组织含水量与AQP4 mRNA表达变化一致。经相关性分析,AQP4 mRNA的表达与脑组织含水量呈正相关(r=0.095,P<0.05)。结论重型脑损伤急性期,AQP4 mRNA表达变化与颅脑损伤后脑水肿的形成和发展密切相关。AQP4可能参与重型脑损伤后脑水肿的形成并起重要作用。

Objective To investigate the expression of aquaporin-4 （AQP4） and its correlation with brain edema during the acute phase of severe traumatic brain injury （TBI） in rats. Methods Fifty-six adult male Wistar rats were randomized into seven experimental groups （0.5, 2, 6, 12, 24, 48 and 72 h post-injury） and one control group. A severe TBI model generated with hydraulic impact was used. At each time spots, the water contents in the brain tissues were measured as wet-to-dry weight ratio and the expression of AQP4 mRNA was assessed by semi-quantitative RT- PCR. Results The expression of AQP4 mRNA was up-regulated 0.5 hours after injury, progressively enhanced from 2 h to 6 h to 12 h, peaked at 24 h （P〈0.05） and remained a high level at 72 h. A similar change was noted for water contents in brain tissues. Correlation analysis showed that the expression of AQP4 mRNA was positively correlated with brain water contents （r=0.095 ,P〈0.05）. Conclusion The changes in AQP4 mRNA expression may be closely related to formation and progression of brain edema during the acute stage of severe traumatic brain injury. AQP4 may be playing an important role in brain edema after severe TBI.