Objectives: To explore the effect of electroacupuncture (EA) at "Baihui" (GV20) and "Shenting" (GV24) on the microvascular structure and related protein expression in the hippocampus of vascular dementia (VD) rat model, and to investigate the mechanism of EA in the treatment of VD.
Methods: A total of 24 SD rats were randomly divided into sham operation, model, EA, and oxiracetam groups, with 6 rats in each group. Multiple cerebral infarction method was used to establish VD model. In the EA group, EA was applied to GV20 and GV24 for 30 min, once daily for 14 days. Rats in the oxiracetam group were treated with oxiracetam (50 mg/kg) by intraperitoneal injection, and the course of treatment was the same as that in the EA group. Learning and memory ability were evaluated by using Morris water maze test and new object recognition experiment. The cerebral blood flow was detected by laser doppler. The microvascular structure in the hippocampus was observed by transmission electron microscopy. The expression of vascular structure related proteins of platelet-derived growth factor receptor (PDGFR)-β, platelet endothelial cell adhesion molecule-1(CD31), neural cadherin N-Cadherin, Zonula occludens protein-1(ZO-1) in the hippocampus were measured by Western blot.
Results: Compared with the sham operation group, the rats in the model group had a significant increase in time of first crossing the platform, a significant decrease in the number of crossing platform and the new object preference index (P<0.05), a significant decrease in cerebral blood flow (P<0.05), and a significant increase in the brain weight (P<0.05). The structure boundary of pericyte and endothelial cells in the microvessels of the hippocampal CA1 area of model group was blurred, accompanied by obvious edema around the vessels and the reduction of tight junctions. The protein expression levels of PDGFR-β, CD31, N-Cadherin, ZO-1 were significantly decreased in the model group compared with those in the sham operation group (P<0.05). Compared with the model group, the time of first crossing the platform of rats in the EA and oxiracetam group was shortened, the number of crossing platform were increased (P<0.05), the cerebral blood flow was increased (P<0.05), the brain weight was decreased (P<0.05), the morphology and structure of pericyte and endothelial cells in the microvessels of hippocampal CA1 area were intact, accompanied by the increase of tight junctions. Additionally, Compared with the model group, the EA group had a significant increase in the new object preference index (P<0.05), the protein expression levels of PDGFR-β, CD31, ZO-1 in the EA group were increased (P<0.05), and the expression of PDGFR-β, N-Cadherin, ZO-1 in the oxiracetam group were increased (P<0.05).
Conclusions: EA at GV20 and GV24 can improve the learning and memory ability of VD rats, and the mechanism may be related to the repair of microvascular structures and improvement of cerebral blood flow.
目的: 观察电针“百会”“神庭”对血管性痴呆（VD）大鼠海马微血管结构及相关蛋白表达的影响，探讨电针治疗血管性痴呆的作用机制。方法: SD大鼠随机分为假手术组、模型组、电针组、奥拉西坦组，每组6只。采用多发性脑梗死法复制VD模型。电针组电针“百会”“神庭”，每次30 min；奥拉西坦组予以奥拉西坦（50 mg/kg）腹腔注射，两组均1次/d，持续14 d。采用Morris水迷宫实验、新物体识别实验评价各组大鼠学习和记忆功能；电子天平测量大脑质量；激光多普勒血流监测仪检测各组大鼠脑血流变化；透射电子显微镜观察各组大鼠海马CA1区微血管结构；Western blot法检测各组大鼠海马微血管结构相关蛋白血小板衍生生长因子受体β（PDGFR-β）、血小板内皮细胞黏附分子-1（CD31）、神经钙黏附蛋白（N-Cadherin）、闭锁小带蛋白-1（ZO-1）蛋白表达情况。结果: 与假手术组比较，模型组大鼠第1次穿越平台时间延长（P<0.05），跨越平台次数减少（P<0.05），新物体认知指数（RI）降低（P<0.05），脑血流量降低（P<0.05），大脑质量增加（P<0.05），海马CA1区微血管周细胞、内皮细胞结构边界模糊，血管周围有明显水肿，紧密连接明显减少，海马组织PDGFR-β、CD31、N-Cadherin、ZO-1蛋白表达水平显著降低（P<0.05）。与模型组比较，电针组和奥拉西坦组大鼠第1次穿越平台时间缩短（P<0.05），跨越平台次数增加（P<0.05），脑血流量显著增加（P<0.05），大脑质量减少（P<0.05），海马CA1区微血管中周细胞、内皮细胞形态结构完整，紧密连接明显增多，海马组织PDGFR-β、ZO-1蛋白表达水平上调（P<0.05）；电针组RI升高（P<0.05），海马组织CD31蛋白表达水平上调（P<0.05）；奥拉西坦组海马组织N-Cadherin蛋白表达水平上调（P<0.05）。结论: 电针“百会”“神庭”能改善VD大鼠学习记忆功能，其机制可能与修复微血管结构、改善脑血流相关。.
Keywords: Electroacupuncture; Microvascular structure; Neural cadherin; Platelet derived growth factor receptor-β; Platelet endothelial cell adhesion molecule; Vascular dementia; Zonula occludens protein-1.