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背景:水通道蛋白4可能是导致脑水肿形成的重要调节因素之一,但水通道蛋白4是否参与脑出血后脑水肿的形成尚未见报道。目的:观察出血性脑水肿病理过程中水通道蛋白4的表达情况,探讨其与脑水肿形成的关系。设计:随机对照动物实验。单位:广西壮族自治区人民医院神经内科和重庆医科大学神经生物学研究室。材料:实验于2003-04/2003-10在重庆医科大学生物学实验室完成。选择健康Wistar大鼠120只,雄性,体质量250～300g,由重庆医科大学实验动物中心提供。方法:实验分为4部分,每部分(n=30)均随机分为对照组(n=5)和手术组(n=25),并将手术组进一步分为出血后6h,1d,3d,5d,7d共5个时相组(n=5)。手术组大鼠麻醉后将定量胶原酶注入脑左侧尾状核建立脑出血模型;对照组只进针不注胶原酶。造模成功标准:将大鼠尾巴提起,瘫痪侧前肢回收后屈曲于腹下,正常侧前肢向地面伸展。实验分为以下4个部分:①采用免疫组化检测水通道蛋白4蛋白的表达。②采用原位杂交法检测水通道蛋白4mRNA的表达。③采用反转录-聚合酶链反应检测水通道蛋白4mRNA的表达。④应用电镜观察大鼠脑水肿的病理改变。主要观察指标:①各组大鼠水通道蛋白4mRNA及其蛋白的表达水平。②造模大鼠脑水肿区的病理改变。结果:手术组大鼠均造模成功,全部大鼠均进入结果分析,无脱失。①各组大鼠水通道蛋白4mRNA及其蛋白的表达水平比较:对照组大鼠水通道蛋白4的表达无明显改变。与对照组相比,手术组大鼠脑出血后6h,水通道蛋白4mRNA和蛋白在脑水肿区表达增强;至第3天,水通道蛋白4mRNA和蛋白的表达达到高峰;1周后,水通道蛋白4的表达仍显著高于对照组(t=12.65,P<0.01)。②脑水肿形成过程中水通道蛋白4mRNA和蛋白的关系:水通道蛋白4mRNA和蛋白的表达呈高度正相关(r=0.8281～0.9821,P<0.01)。③手术组大鼠脑水肿区相应的病理改变:在脑出血后1～3d内为逐渐加重的细胞内水肿,到第3天,脑水肿进一步加剧,出现血管源性水肿,而且有部分组织变性和坏死。结论:脑出血后水通道蛋白4表达明显增强,提示水通道蛋白4可能参与了出血性脑水肿的发生发展过程。抑制水通道蛋白4的表达可能是防治脑水肿的一种有效途径。
BACKGROUND: Aquaporin 4 may be one of the most important regulators of brain edema formation. However, whether aquaporin 4 participates in cerebral edema after intracerebral hemorrhage has not been reported yet. Objective: To observe the expression of aquaporin 4 during hemorrhagic brain edema pathological process and to explore its relationship with the formation of cerebral edema. Design: Randomized controlled animal experiments. SETTING: Department of Neurology, People’s Hospital of Guangxi Zhuang Autonomous Region and Department of Neurobiology, Chongqing Medical University. MATERIALS: Experiments were performed at the Biology Laboratory of Chongqing Medical University from April 2003 to October 2003. A total of 120 healthy Wistar rats were selected, weighing 250-300 g male and provided by Experimental Animal Center of Chongqing Medical University. Methods: The experiment was divided into 4 parts and each part (n = 30) was randomly divided into control group (n = 5) and operation group (n = 25). The operation group was further divided into 6 hours, 1 day, 5d, 7d total 5 phase group (n = 5). Rats in the operation group were given intracerebral hemorrhage by injection of quantitative collagenase into the left caudate nucleus after anesthesia. In the control group, only collagenase was not injected into the needle. Modeling success criteria: the rat tail lifted, paralyzed forelimb recovery after buckling in the abdomen, the normal side of the forelimb to the ground stretch. The experiment is divided into the following four parts: ① immunohistochemical detection of aquaporin 4 protein expression. ② using in situ hybridization detection of aquaporin 4 mRNA expression. Reverse transcription - polymerase chain reaction was used to detect the expression of aquaporin 4 mRNA. ④ electron microscopy pathological changes of rat brain edema. MAIN OUTCOME MEASURES: ① The expression of aquaporin 4 mRNA and protein in rats in each group. ② pathological changes in rat brain edema area. Results: All the rats in the operation group were successfully established. All the rats were involved in the analysis of the results without any loss. ①Compared with the expression of aquaporin 4 and its protein in the rats in each group, the expression of aquaporin 4 in the control group did not change significantly. Compared with the control group, the expression of aquaporin 4 mRNA and protein in brain edema area increased 6 h after intracerebral hemorrhage in rats in operation group. The expression of aquaporin 4 mRNA and protein peaked on the 3rd day. After 1 week, Protein 4 expression was still significantly higher than the control group (t = 12.65, P <0.01). The relationship between aquaporin 4 mRNA and protein during the process of brain edema: The expression of aquaporin 4 and protein was highly positively correlated (r = 0.8281 ~ 0.9821, P <0.01). ③ The corresponding pathological changes in brain edema area of rats in operation group: gradual aggravation of intracellular edema within 1 ~ 3 days after intracerebral hemorrhage. On the third day, brain edema further aggravated with vasogenic edema, and some tissue degeneration And necrosis. Conclusion: The expression of aquaporin 4 after intracerebral hemorrhage was significantly increased, suggesting that aquaporin 4 may be involved in the development of hemorrhagic brain edema. Inhibition of aquaporin-4 expression may be an effective way to prevent cerebral edema.