大鼠重型颅脑损伤急性期水通道蛋白4的表达

目的探讨水通道蛋白（AQP4）在大鼠重型脑外伤急性期的表达变化及其与脑水肿间的关系。方法49只成年雄性SD大鼠,随机分为对照组及实验组（伤后4h、8h、12h、24h、5d共5组）。制作重度冲击加速性损伤模型,分别于伤后4h、8h、12h、24h、72h、5d采用干湿比重法测脑组织含水量,原子吸收分光光度法测定Na^＋、K^＋含量,Evans Blue（EB）测定法观察大鼠血-脑屏障（BBB）通透性变化,半定量逆转录聚合酶链反应（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4h开始表达上调,8h、12h依次增高,24h达到峰值（P〈0.05）,3d时仍维持较高水平,伤后5d有所降低。脑含水量、Na^＋含量的变化与AQP4 mRNA表达变化一致。经相关性分析,AQP4 mRNA的表达与脑含水量及脑EB含量均呈正相关（P〈0.05）。结论重型脑损伤急性期,AQP4 mRNA表达的变化与颅脑损伤后BBB的破坏及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。

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

Objective To investigate the expression of aquaporin-4(AQP4) and its correlation with brain edema at the acute phase after severe traumatic brain injury(TBI) in rats.Methods Forty-nine adult male SD rats were divided into the experimental groups designated 4 h,8 h,12 h,24 h,72 h and 5 d after the injury and control group.A severe TBI model was used.The water contents in the brain tissues were measured by the wet and dry weight method.The sodium(Na+) and potassium(K+) contents were measured by atomic absorption spectrophotometry.The blood-brain barrier(BBB) permeability was measured by Evans blue extravasation.The expression of AQP4 mRNA was assessed by RT-PCR.Results The expression of AQP4 mRNA significantly increased after 4 hours,8 hours,12 hours,get the highest level at 24 hours(P<0.05),keep high level at 3d and then decreased gradually at 5 d.The changes of brain water content and Na+ content was the same as that of AQP4 mRNA expression.Correlative analysis results showed that the expression of AQP4 mRNA was positive correlated with the brain water content(P<0.05) and the change of EB content(P<0.05).Conclusion The change of AQP4 mRNA expression is closely related to the destruction of BBB and the formation and development of brain edema during the acute stage after severe traumatic brain injury.AQP4 maybe participated in the brain edema formation after severe traumatic brain injury and plays an important role.