尼莫地平对大鼠脑出血周边组织AQP4表达的影响

Effects of nimodipine on the expression of AQP4 around the edema after intracerebral hemorrhage in rats

目的观察尼莫地平对ICH周边组织AQP4表达、细胞内Ca2+浓度变化及对BBB保护作用的影响。方法参考Rosenberg等方法复制大鼠ICH动物模型,随机将120只Wistar大鼠分为假手术组(n=20)、脑出血组(n=50)和尼莫地平治疗组(n=50),脑出血后分别观察6h、1d、3d、5d、7d等5个时间点。用免疫组化法测定ICH周边组织AQP4的表达,用荧光标记检测胞内Ca2+及EB作为示踪剂监测BBB的损伤程度,用干湿法测定脑组织含水量。结果 (1)脑出血组3d含水量达到高峰,第7天明显下降,但仍高于正常水平;尼莫地平组3d含水量达高峰,但低于脑出血组;(2)脑出血后6h血肿周边组织EB含量增加,1d达高峰,7d已明显下降;尼莫地平干预后各时间点EB含量明显低于脑出血组,高于假手术组,7d后EB含量恢复正常;(3)脑出血后6h血肿周边组织AQP4表达及细胞内Ca2+浓度逐渐增高,3d达高峰,7d后下降明显;尼莫地平组血肿周边组织AQP4表达及细胞内Ca2+浓度逐渐增高,3d达高峰,明显低于脑出血组。结论 (1)Ca2+能促进AQP4的过度表达,使BBB通透性增加,参与出血性脑水肿的病理过程;(2)尼莫地平可阻断Ca2+向细胞内过度内流,进而降低AQP4的表达,减轻脑水肿程度,为脑出血治疗提供新的靶点。

Objective To study the influence of nimodipine in the dynamic expression of Aquaporin-4 and the concentration of free intracellular calcium,blood-brain barrier and brain water content around intracerebral hemorrhage（ICH） in rats.Methods A rats model of ICH was made according to the methods of Rosenberg,160 wistar rats were randomly separated into sham group（n=20）,ICH group（n=50）,nimodipine group（n=50）,and observed the expression of AQP4 and the concentration of free intracellular calcium by the time of 6h,1d,3d,5d,7d.Result（1） On 3d in the ICH group,the brain water content peaked and on 7d it decreased but still higher than normal.On 3d in the nimodipine group,the brain water content peaked but still lower than ICH group.（2） After intracerebral hemorrhage,the EB content around the area of hemorrhage increased after 6h and on the first day it peaked but began to decrease significantly on 7d.By the passage of time,EB content significantly decreased in nimodipine group than that of in ICH group and higher in sham group,by 7d it became normal.（3）After 6h of hemorrhage,the edema around the hemorrhagic area,AQP4 expression and intracellular calcium concentration gradually increased.On 3d,it peaked and on 7d it significantly decreased.In nimodipine group,AQP4 expression of edema around hemorrhagic tissue and intracellular calcium concentration gradually increased,on 3d it peaked but significantly lower than ICH group.Conclusion In the pathogenesis of hemorrhage,calcium induces AQP4 over expression,increases BBB infiltration and induces brain edema.Nimodipine can block intracellular calcium transport,therefore decrease AQP-4 expression and inhibit brain edema,which offers us a new target in the therapy of ICH.