| Objective:To observe the effect of electroacupuncture preconditioning(EAP) on BAIHUI (GV20) and SHUIGOU (GV26) with different time course on brain water content,meanwhile observe the influence of EAP to the blood brain barrier(BBB) ultrastructure changes. From the EAP effect on the expression of AQP-4and Claudin-5in BBB in rats with middle cerebral artery occlusion(MCAO) ischemia injury, further investigate the possible mechanism of EAP protection effect on BBB.Method:Experiment1:32male SD rats were randomly divided into4groups(n=8):a sham-operatedgroup(SH), a model group(M), an EAP7day group(EAP7d) and an EAP15daygroup(EAP15d). Apart from the model group and the SH group, each EAP groups were treated with EAP according relevant cumulative time. The rats in EAP groups and model group were established to MCAO ischemia-reperfusion models, other than SH group rats were without ligating artery nor inserting intraluminal monofilament, the rest of procedure the same as the other groups. Moreover, to control the quality of MCAO rat models, monitoring the middle cerebral artery blood flow preoperation and postoperation, then carrying out neural behavioral score after ischemia-reperfusion anesthesia. Finally,24h after MCAO surgery, samples were taken for detection of brain water content. In addition,16SD rats were randomly divided into2groups(n=8):an M group and an EAP15d group,being nursed and treated the same as those groups of the same name. And these rats were used to observe BBB ultrastructure under transmission electron microscope(TEM). Experiment2:64male SD rats were randomly divided into4groups(n=16):SH group, M group, EAP7d group and EAP15d group, being nursed and treated the same as experiment1. When the taking samples, the rat brain in each group were randomly then divided into2subgroups(n=8), one group for detecting positive cell expression of AQP-4and Claudin-5with immunohistochemical method, the other one for detecting mRNA expression of AQP-4and Claudin-5with fluorescent quantitative PCR method. Result:The quality control of the rat MCAO models was in condition. The cerebral blood flow of rats in EAP groups and model group decreased in rats as the basis of the value of45±10%. The neural behavioral score of EAP groups and model group was significantly higher than that of sham-operated group (P<0.01), compared with model group rats, the score of EAP7day group rats was significantly reduced (P<0.05), that of EAP15day group rats was more significantly reduced (P<0.01), and that of EAP15day group rats also lower than that of EAP7d group(P<0.05). The brain water content of EAP7d group rats significantly alleviated comparing the model group (P<0.05) while that of EAP15d group rats much more significantly alleviated(P<0.01). And the brain water content of EAP15d group rats was not so high as that of EAP7d group rats(P<0.05). Comparing the model group with EAP15d group, we found EAP could mitigate BBB ultrastructure changes inducing by ischemia-reperfusion injury. Ischemia-reperfusion injury, which increased the positive cells and mRNA expression of AQP-4in the cerebral cortex. EA preconditioning for7d and15d, on the other hand, partially reverses the AQP-4up-regulation induced by CIR injury (P<0.01),. The positive cells and mRNA expression of Claudin-5in model group and EAP groups were significantly decreased compared with the SH group. EA preconditioning for7d and15d obviously supressed the decrease of Claudin-5(P<0.01).Conclusion:1. EAP could improve the nerve function, the cerebral edema and the BBB ultrastructure pathological damage of ischemia-reperfusion injury in rats.2. EAP could promote the expression of Claudin-5and inhibite that of AQP-4in blood-brain barrier of cerebral ischemia-reperfusion injury.3. The mechanism EAP protective effect on function and morphology of BBB may realize by up-regulating Claudin-5expression and down-regulating AQP-4expression.4. EAP for long term had more significantly protective effect on blood-brain barrier in rats with ischemia-reperfusion injury. |
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