实验性脑出血后水通道蛋白4的表达变化(英文)

Changes of aquaporin-4 expressions after experimental intracerebral hemorrhage

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 candidates for inducing the brain edema in ischemic stroke, however, it still has not been reported whether aquaporin-4 is involved in the formation of brain edema after intracerebral hemorrhage （ICH）. OBJECTIVE： To observe the expression of aquaporin-4 of cerebral tissue in the pathologic course of hemorrhagic cerebral edema in rats, and investigate its relationship with the formation of brain edema following ICH. DESIGN： A randomized controlled experimental study. SETTING： Department of Neurology, People＇s Hospital of Guangxi Zhuang Autonomous Region; Research Room of Neurobiology, Chongqing University of Medical Sciences. MATERIALS： This experiment was carried out in the Research Room of Neurobiology, Chongqing University of Medical Sciences between April and October 2003. Totally 120 adult healthy male Wistar rats, weighing 250-300 g, were provided by the Experimental Animal Center of Chongqing University of Medical Sciences. METHODS： The experiment had four parts, each part （n=30） was divided into the control group （n=5） and operation group （n=25）, and then the latter was subdivided into 6-hour, 1, 3, 5 and 7-day following ICH groups with 5 rats in each group. In the operation group, ICH models were established by infusing collagenase into left caudate nucleus of rats unilaterally. The operative process in the control group was the same as that in the operation group except for infusing collagenase. Standards for successful model establishment： the paralytic forelimb flexed under abdomen after withdrawal, and the normal forelimb extended to the ground. ① The expression of aquaporin-4 was detected with immunohistochemistry. ② The expression of aquaporin-4 mRNA was assessed with in situ hybridizution. ③ The expression of aquaporin-4 mRNA was assessed with reverse transcription polymerase chain reaction （RT-PCR）.④The pathological changes of hemorrhagic edema were observed under transmission electron microscope. MAIN OUTCOME MEASUREs： ① expression of aquaporin-4 mRNA and protein; ② pathological changes of hemorrhagic edema. RESULTS： The model establishments were all successful in the operation group, and all the rats were involved in the analysis of results without deletion. ① Comparison of the expression of aquaporin-4 mRNA and protein among the groups. There was no significant change in the control group. As compared with the control group, there was a significant increase of the expressions of aquapofin-4 mRNA and protein in the edematous tissue at 6 hours following ICH, and then reached the peaks at 3 days, and the expression of aquaporin-4 was still significantly higher than that in the control group at one week following ICH （t=12.65, P 〈 0.01）. ② The corresponding sequential pathological changes in the edematous tissue of rats in the operation group： There was a gradual increase of intracellular edema within 1-3 days following ICH, and then the brain edema became aggravated at 3 days, an emergence of vasogenic edema and local edema tissue degeneration and necrosis were observed. CONCLUSION： The increased expression of aquaporin-4 was obviously enhanced following ICH, suggesting that aquaporin-4 may play an important role in the pathological course of hemorrhagic brain edema, and inhibition of aquaporin-4 expression may be an effective pathway to prevent and treat brain edema.