电针对局灶性脑缺血再灌注大鼠水通道蛋白-4的调节作用

目的:探讨电针、脑水肿和水通道蛋白-4(AQP4)之间的变化关系。方法:选用健康SD雄性大鼠,阻塞大鼠大脑中动脉(MCAO),制作缺血性脑水肿模型。动物分为正常对照组、模型组和电针处理组,每组大鼠36只。电针处理组电针“水沟”“百会”穴,0.8-1.0mA,疏密波,电针30min。用CV染色法测定脑水肿肿胀率,用IgG免疫组化法测定脑组织中的IgG来反映血脑屏障(BBB)的通透性,采用免疫组化和逆转录聚合酶链式反应(RT-PCR)技术分别观察AQP4蛋白和mRNA在脑组织中表达的变化。结果:MCAO12h后,模型组脑水肿所引起的缺血侧脑半球开始肿胀,IgG开始外渗,AQP4蛋白和mRNA的表达开始上升,随着梗塞时间的延长,肿胀和外渗逐渐加重,AQP4的表达进一步增多,在72h均达到高峰。而电针能够明显减轻脑水肿所引起的缺血侧脑半球的肿胀,减少IgG外渗,降低AQP4蛋白和mRNA的表达。结论:电针可减轻脑缺血后脑水肿肿胀率,同时改善BBB的损伤程度。电针的这种保护作用可能与AQP4表达下调有一定的关系。

Regulative Effect of Electroacupuncture on Aquaporin-4 in Rats with Focal Cerebral Ischemia/reperfusion

OBJECTIVE: To study the effect of electroacupuncture (EA) on changes of aquaporin-4 (AQP4) expression in rats with cerebral ischemia/reperfusion(CI/R). METHODS: One hundred and seventy male Sprauge-Dawley rats were randomized into control (n = 50), CI/R model (n = 60) and EA (n = 60) groups, and the later 2 groups were further divided into 6 h, 12 h, 24 h, 48 h and 72 h subgroups, with 12 cases in each. CI/R model was established by occlusion of the middle cerebral artery (MCAO). EA (3.85/6.25 Hz, 0.8 - 1.0 mA) was applied to "Shuigou" (GV 26) and "Baihui" (GV 20) for 30 min. Transcardial perfusion was conducted with normal saline + paraformaldehyde in rats of different groups for taking brain tissue samples. The degree of brain edema was detected by cresyl violet stain method, permeability of the blood-brain barrier (BBB) reflected with IgG value in brain tissue was displayed by immunohistochemistry, and AQP4 protein and mRNA expression of corpora striata (CS) were detected by using immunohistochemistry (ABC) and RT-PCR techniques respectively. RESULTS: Twelve hours after CI/R, the hemisphere of brain began to get swelling significantly and the exosmose state of IgG became evidently; compared with the corresponding phases of model group, the swell rates in 24 h, 48 h and 72 h subgroups of EA group were significantly lower (P < 0.05, 0.01), and nearly no IgG immunoreaction positive products were found in different phases of EA group. The expression of AQP4 protein and mRNA increased significantly from 12 h and 24 h on separately in model group, while the expression in EA group was markedly weaker. The ratios of AQP4 mRNA and beta-actin mRNA of CS on the affected side of the brain from 24 h to 72 h of EA group were significantly lower than those of model group (P < 0.05, 0.01). CONCLUSION: EA can reduce the degree of brain edema induced by CI/R and improve the degree of BBB injury, which may be related to its effect in down-regulating AQP4 expression.