摘要
目的观察大鼠脑挫裂伤形成的创伤性脑水肿病理过程中水通道蛋白-4（AQP4）的表达与脑水肿形成之间的关系以及脑挫裂伤时多剂量应用甘露醇对水通道蛋白-4表达的影响。方法采用自由落体脑损伤模型方式制作大鼠左顶叶脑挫裂伤模型，通过对应用多剂量甘露醇前后（1、6、12、24、48h）脑挫裂伤组织免疫组织化学方法和半定量逆转录-聚合酶链反应（RT—PCR）检测AQP4 mRNA的表达，干湿重法测定脑组织水含量。结果与对照组比较，脑挫裂伤后自6h开始脑组织水含量持续增加（P〈0．05），并在24h时达到高峰；AQP4 mRNA和蛋白质在脑水肿区表达增强，挫裂伤未进行甘露醇治疗组（IR）6h AQP4 mRNA（吸光度值，A）由0．33±0．04上升到0．58±0．05（P〈0．05），48h AQP4 mRNA（吸光度值，A）由12h的0．61±0．07上升到0．78±0．10（P〈0．05）；甘露醇应用后（MI组）挫裂伤灶AQP4 mRNA和蛋白质从6h开始明显增高（P〈0．05），并随着时间推移含量持续增高，甘露醇应用后6h和12h与应用前相应时间组之间差异无统计学意义（P〉0．05）；伤后24h和48h明显高于应用前相应时间组，两者差异有统计学意义（P〈0．05）。在整个脑水肿的形成过程中AQP4 mRNA和脑组织含水量呈正相关（rs〉0．780，Ps〈0．05）。结论脑挫裂伤后AQP4 mRNA和蛋白的表达明显增强，提示AQP4参与了脑挫裂伤创伤性脑水肿的发生发展过程，水通道蛋白的改变可能是甘露醇出现“反跳现象”的重要原因之一。
Objective To study the relationship between the expression of aquaporin4 （AQP4） and cerebral edema formation during the pathologic course of traumatic brain injury animal model caused by controlled focal cortical contusion compact and injections of mannitol to evaluate the effect of mannitol on brain edema and AQP4. Methods 127 adult Wistar rats received a focal cortical contusion of the parietal cortex,7 of which died and were excluded from the study,and the remaining 120 were randomly divided into two groups, one group with injection of mannitol （ 1.0 g/kg q6h）, MI group ; another group without injection of mannitol, IR group. Additional 12 rats underwent a craniectomy, but no trauma was inflicted （RH group）. Animals were killed at lst,6th, 12th,24th and 48th h. The rat brains were examined for water content by comparing the wet and dry weights of the injurious hemisphere. AQP4 mRNA was detected by reverse transcription-polymerase chain reaction. Immunohistochemistry was used to measure AQP4 protein expression. Results As compared with the control group, there appeared a significant increase in water content, AQP4 mRNA and protein expression on the edematous tissue at 6th h in rats （P 〈 0.05 ）. At 24th h, the water content reached its maximum ： （ 1 ） In IR group, at 6th h AQP4 mRNA expression （ absorbance, A） was increased from 0.33 ± 0.04 to 0.58± 0.05 （ P 〈 0.05） , and AQP4 protein expression increased from 17.85 ±3.98 to 42.15 ±7.32 at the same time; At 48th h AQP4 mRNA expression reached at 0.78 2 0.10 and AQP4 protein expression at 59.45 ± 3.48 （P 〈 0.01 ）, which was significantly higher than at 12th h （P 〈0.05） ; （2）. In MI group,at 12th h AQP4 mRNA expression was increased from 0.31 ±0.04 to 0.61 ±0.07 （P 〈0.01 ） ,and AQP4 protein expression increased froml7.78 2 3.75 to 46.75 ±2.91 at the same time; At 48th h,AQP4 mRNA expression reached at 0.90 20.04 and AQP4 protein expression at 68.45 2 1.82 （ P 〈 0.01 ） ,which was significantly higher than at 12th h （ P 〈 0.05 ） ; （ 3 ） There was no significant difference in water content, AQP4 mRNA and protein expression in MI and IR groups at 6th h and 12th h on the edematous tissue （P〉0. 05） ; （4） At 24th h and 48th h,water con- tent,AQP4 mRNA and protein expression in MI group were significandy higher than in IR group （P 〈 0.05 ） ; （5） The AQP4 mRNA expression showed a positive relationship with the water content （rs 〉 0. 780,Ps 〈 0.05 ）. Conclusion An up-regulation of AQP4 occurs at the site of traumatic brain injury, suggesting that AQP4 should play an important role in the pathological course of the cerebral edema. The upregulation of AQP4 may play a role in the rebound phenomenon which was induced by the administration of multidoses of mannitol.
出处
《中华实验外科杂志》
CAS
CSCD
北大核心
2008年第1期103-106,共4页
Chinese Journal of Experimental Surgery
