电针改善大脑中动脉闭塞模型大鼠空间学习记忆的机制研究

Mechanism of electroacupuncture in improving spatial learning memory in a rat model of middle cerebral artery occlusion

目的探讨电针对大脑中动脉闭塞(MCAO)模型大鼠空间学习记忆的影响及相关机制。方法40只SD大鼠随机数字表法分为假手术组、模型组、电针穴位组、电针非穴组,每组10只。采用线栓塞法建立MCAO大鼠模型,电针穴位组给予电针百会和神庭,每次20 min,每天1次,治疗7 d,电针非穴组电针大鼠胁部以下,髂嵴以上10~15 mm非穴位处,余同电针组,假手术组和模型组仅给予同等时间的抓取和固定。观察各组大鼠神经行为学评分、水迷宫空间探索实验和定向巡航实验结果,正电子发射断层-X线计算机断层组合系统(PET-CT)检测大鼠海马区葡萄糖摄取率,蛋白质印迹法检测葡萄糖转运蛋白1(GLUT1)和葡萄糖转运蛋白3(GLUT3)表达水平。结果与模型组比较,电针穴位组大鼠干预第5、7天神经行为学评分显著降低[(1.55±0.51)分比(2.05±0.45)分,(1.30±0.47)分比(1.96±0.26)分,P均<0.05];干预第3、4、5、6天逃避潜伏期明显缩短[(58.65±10.55)s比(86.18±15.86)s、(45.16±11.76)s比(73.89±14.85)s、(36.48±11.27)s比(63.23±13.87)s、(25.41±8.73)s比(50.77±11.57)s,P均<0.01];穿越平台次数增加[(2.93±0.95)次比(1.53±0.53)次,P<0.01];左/右侧海马区葡萄糖摄取率比值增加[(86.75±25.13)%比(80.28±24.00)%,P<0.05];脑组织含水量减少[(78.27±0.60)%比(84.45±1.08)%,P<0.05];左侧海马区GLUT1、GLUT3表达水平增加[(73.22±10.48)%比(56.39±12.21)%、(79.18±9.82)%比(58.37±16.07)%,P均<0.05]。与电针非穴组比较,电针穴位组大鼠干预第5、7天神经行为学评分显著降低[(1.55±0.51)分比(2.03±0.45)分、(1.30±0.47)分比(1.82±0.47)分,P均<0.05];第3、4、5、6天逃避潜伏期明显缩短[(58.65±10.55)s比(84.48±14.36)s、(45.16±11.76)s比(70.78±13.93)s、(36.48±11.27)s比(59.94±11.02)s、(25.41±8.73)s比(48.97±10.44)s,P均<0.01];穿越平台次数增加[(2.93±0.95)次比(1.63±0.50)次,P<0.01];左/右侧海马区葡萄糖摄取率比值增加[(86.75±25.13)%比(81.87±25.67)%,P<0.05];脑组织含水量减少[(78.27±0.60)%比(82.44±0.40)%,P<0.05];左侧海马区GLUT1、GLUT3表达水平增加[(73.22±10.48)%比(58.57±8.74)%、(79.18±9.82)%比(62.10±9.98)%,P均<0.05]。结论电针百会和神庭可能通过调节GLUT1和GULT3的表达改善MCAO模型大鼠脑内葡萄糖代谢水平,从而改善其空间学习记忆能力。

Objective To assess the effects and underlying mechanisms of electroacupuncture(EA)in improving spatial learning and memory in a rat model of the middle cerebral artery occlusion(MCAO).Methods Forty Sprague-Dawley rats were randomly divided into sham operation,MCAO model,EA,and non-acupoint groups according to the random number table method,with 10 rats in each group.The MCAO model was established using thread embolization.In the EA group,EA was administered at the Baihui and Shenting points for 20 minutes each time,once daily,for 7 days.In the non-acupoint group,EA was performed at a non-acupoint location between 10~15 mm below the ribs and above the iliac crest,following the same procedures as in the EA group.The sham operation and the model groups were given the same duration of grasping and fixation.Neurobehavioral scores,Morris water maze spatial exploration test,and direct navigation test results were recorded for each group.Glucose metabolism in the hippocampus was assessed using a positron emission tomography-computed tomography system.The expression levels of glucose transporter 1(GLUT1)and GLUT3 were detected using Western blotting.Results Compared with the model group,the EA group showed significantly lower neurobehavioral scores on the 5th and 7th days[(1.55±0.51)vs.(2.05±0.45),(1.30±0.47)vs.(1.96±0.26),all P<0.05].The escape latency was significantly reduced on the 3th,4th,5th,and 6th days of intervention[(58.65±10.55)s vs.(86.18±15.86)s,(45.16±11.76)s vs.(73.89±14.85)s,(36.48±11.27)s vs.(63.23±13.87)s,(25.41±8.73)s vs.(50.77±11.57)s,all P<0.01].Additionally,the number of crossing the platform increased[(2.93±0.95)vs.(1.53±0.53),P<0.01].Glucose uptake rate in the left/right hippocampal regions increased[(86.75±25.13)%vs.(80.28±24.00)%,P<0.05]while the brain tissue water content decreased[(78.27±0.60)%vs.(84.45±1.08)%,P<0.05].Furthermore,the expression levels of GLUT1 and GLUT3 in the left hippocampal region increased[(73.22±10.48)%vs.(56.39±12.21)%,(79.18±9.82)%vs.(58.37±16.07)%,P<0.05].Compared with the non-acupoint group,the EA group showed significantly lower neurobehavioral scores on the 5th and 7th days[(1.55±0.51)vs.(2.03±0.45),(1.30±0.47)vs.(1.82±0.47),all P<0.05].The escape latency was significantly reduced on the 3th,4th,5th,and 6th days of intervention[(58.65±10.55)s vs.(84.48±14.36)s,(45.16±11.76)s vs.(70.78±13.93)s,(36.48±11.27)s vs.(59.94±11.02)s,(25.41±8.73)s vs.(48.97±10.44)s,all P<0.01].Additionally,the number of crossing the platform increased[(2.93±0.95)vs.(1.63±0.50),P<0.01].Glucose uptake rate in left/right hippocampal regions increased[(86.75±25.13)%vs.(81.87±25.67)%,P<0.05]while the brain tissue water content decreased[(78.27±0.60)%vs.(82.44±0.40)%,P<0.05].Furthermore,the expression levels of GLUT1 and GLUT3 in the left hippocampal region increased[(73.22±10.48)%vs.(58.57±8.74)%,(79.18±9.82)%vs.(62.10±9.98)%,all P<0.05].Conclusion EA at Baihui and Shenting points may improve the spatial learning and memory abilities of MCAO model rats by regulating the expression levels of GLUT1 and GLUT3,thereby enhancing glucose metabolism in the brain.