电针改善缺血性卒中模型小鼠认知障碍的作用机制研究

Study on the Mechanism of Action of Electro-acupuncture in Improving Cognitive Impairment in Mice Model with Ischemic Stroke

【目的】探讨电针改善缺血性卒中模型小鼠认知障碍的作用机制。【方法】将45只8周龄雄性C57BL/6小鼠随机分为假手术组、模型组与电针组。随机选取33只采用大脑中动脉闭塞法诱导缺血性卒中模型,其余12只作为假手术组。共有23只小鼠造模成功,将其随机分为模型组11只、电针组12只。电针组给予电针治疗,取百会、大椎穴,直刺2~3 mm,接通电针仪,连续15 d。比较各组小鼠对新物体偏好指数,通过水迷宫实验比较各组小鼠逃避潜伏期、平台穿越次数和平台象限滞留时间比,高尔基染色观察各组小鼠海马CA 1区神经元形态,蛋白质免疫印迹实验观察各组小鼠海马组织Aβ斑块沉积和APP表达。【结果】(1)模型组小鼠对新物体偏好指数显著减少,与假手术组比较,差异有统计学意义(P<0.05);电针组小鼠对新物体偏好指数显著增加,与模型组比较,差异有统计学意义(P<0.05)。(2)模型组小鼠第3、4天逃避潜伏期延长,与假手术组比较,差异有统计学意义(P<0.05);电针组小鼠第4天逃避潜伏期缩短,与模型组比较,差异有统计学意义(P<0.05)。(3)模型组小鼠平台穿越次数和平台象限滞留时间比均显著减少,与假手术组比较,差异均有统计学意义(P<0.05);电针组小鼠平台穿越次数和平台象限滞留时间比均显著增加,与模型组比较,差异有统计学意义(P<0.05)。(4)模型组小鼠海马神经元树突与同心圆交叉点数量减少,与假手术组比较,模型组同心圆与胞体的距离为100、140、180μm时,差异有统计学意义(P<0.05);电针组小鼠海马神经元树突与同心圆交叉点数量增加,与模型组比较,电针组同心圆与胞体的距离为100、140、180μm时,差异有统计学意义(P<0.05)。(5)模型组小鼠树突分支数量显著减少,与假手术组比较,差异有统计学意义(P<0.05);电针组小鼠树突分支数量显著增加,与模型组比较,差异有统计学意义(P<0.05)。(6)模型组小鼠脑组织中Aβ沉积增加,与假手术组比较,差异有统计学意义(P<0.05);电针组小鼠海马组织中的Aβ沉积减少,与模型组比较,差异有统计学意义(P<0.05)。模型组小鼠脑组织中APP表达增加,与假手术组比较,差异有统计学意义(P<0.05);电针组小鼠海马组织中的APP表达减少,与模型组比较,差异有统计学意义(P<0.05)。【结论】电针能够改善缺血性卒中模型小鼠的认知障碍,其作用机制可能与调节神经元形态、抑制Aβ沉积有关。

Objective To investigate the mechanism of action of electro-acupuncture(EA)in improving cognitive impairment in mice model with ischemic stroke.Methods A total of 458-week-old male C57BL/6 mice were randomly divided into the sham-operation group,the model group and the EA group.Thirty-three mice were randomly selected to induce ischemic stroke model by middle cerebral artery occlusion,and the remaining 12 were used as the sham-operation group.A total of 23 mice were successfully modeled and randomly divided into 11 in the model group and 12 in the EA group.The EA treatment was applied to the“Baihui”(DU20)and“Dazhi”(CV14)points for 15 days.The preference index for new objects was compared between the mice in each group,and the latency to evade,the times of platform crossings and the retention time ratio in the platform quadrant were compared between the mice in each group by the water maze experiment.The neuronal morphology of the CA1region of the hippocampus was observed by Golgi staining,and the Aβplaque deposition and amyloid precursor protein(APP)expression in the hippocampus were observed by protein immunoblotting.Results(1)The preference index for new objects in the model group was significantly decreased compared with that in the sham-operation group(P<0.05);the new object preference index of mice in the EA group was significantly increased compared with that in the model group(P<0.05).(2)The escape latency of the model group was prolonged on the third and forth day,the difference being statistically significant compared with the sham-operation group(P<0.05).The escape latency of the EA group on the fourth day was shorter than that of the model group,the difference being statistically significant(P<0.05).(3)The number of platform crossing and the retention time ratio of platform quadrant in the model group were significantly reduced,the differences being statistically significant compared with the sham-operation group(P<0.05).The times of platform crossing and the retention time ratio of platform quadrant in the EA group were significantly increased,the differences being statistically significant compared with the model group(P<0.05).(4)The number of intersections between dendrites and concentric circles of hippocampal neurons in the model group was decreased,and the distances between concentric circles and cell body in the model group were 100,140,180μm,the differences being statistically significant(P<0.05).The number of intersections between dendrites and concentric circles of hippocampal neurons in the EA group was increased,and the distances between concentric circles and cell body in the EA group were 100,140,180μm,the differences being statistically significant(P<0.05).(5)The number of dendritic branches in the model group was significantly reduced compared with that in the sham operation group(P<0.05);the number of dendritic branches in the EA group was significantly increased compared with that in the model group(P<0.05).(6)Aβdeposition in the brain tissue of the model group was increased,the difference being statistically significant compared with that of the sham-operation group(P<0.05).Aβdeposition in hippocampus of mice in the EA group was decreased compared with that in the model group(P<0.05).The expression of APP in brain tissue of the model group was increased,the difference being statistically significant compared with that of the sham-operation group(P<0.05).APP deposition in hippocampus of mice in the EA group was decreased compared with that in the model group,the difference being statistically significant(P<0.05).Conclusion EA has effects in improving cognitive impairment in mice model with ischemic stroke,and its mechanism of action may be related to the regulation of neuronal morphology and inhibition of Aβdeposition.