纳洛酮与舒必利对大鼠脑震荡后空间学习记忆及海马CA3区锥体细胞影响的对照研究

摘要

目的 研究比较纳洛酮和舒必利对大鼠脑震荡后空间学习记忆能力及海马CA3区锥体细胞影响的异同,并对可能发生的机制进行探讨.方法 用金属单摆打击装置制作SD大鼠脑震荡模型,将32只大鼠随机分为4组:假打击组(6只)、脑震荡组(8只)、脑震荡+纳洛酮治疗组(以下简称纳洛酮治疗组,9只)、脑震荡+舒必利治疗组(以下简称舒必利治疗组,9只).用Morris水迷宫训练方法 ,评价动物的空间学习记忆能力;用Nissl染色对海马CA3区锥体细胞计数;用激光共聚焦显微镜和钙荧光探针flou-3/AM技术,观察海马CA3区锥体细胞内钙离子荧光量值.结果 (1)行为学:打击后第8～13天脑震荡组隐匿平台逃避潜伏期长于假打击组、纳洛酮治疗组、舒必利治疗组(P＜0.01);穿越原平台位置的次数[(2.0±0.8)次/min]少于假打击组[(5.1±0.6)7欠/min]、纳洛酮治疗组[(4.8±1.0)次/min]、舒必利治疗组[(4.6±1.0)次/min],均P＜0.01.(2)海马CA3区锥体细胞计数:假打击组[(62.7±3.4)个]高于脑震荡组[(49.8±1.7)个]、纳洛酮治疗组[(57.3±1.5)个]和舒必利治疗组[(54.8±1.7)个],均P＜0.01;而纳洛酮和舒必利治疗组高于脑震荡组(P＜0.01);纳洛酮治疗组又高于舒必利治疗组(P＜0.01).(3)海马CA3区锥体细胞内游离钙荧光量:脑震荡组[(3.0±0.6)×106]高于假打击组[(1.0±0.3)×106]、纳洛酮治疗组[(0.9±0.4)×106]和舒必利治疗组[(1.1±0.3)×106],均P＜0.01.结论 大鼠脑震荡后学习记忆缺失与海马CA3区锥体细胞数减少有关;纳洛酮和舒必利对这种损害均有保护作用.%Objective To compare the effects of naloxone,a competitive opioid receptor alltagonist,with sulpiride,a dopamine D2 receptor antagonist,on spatial learning and memory deficits and the pvramidal cells in hippocampus CA3 area following cerebral concussion.Methods A metallic pendulum-striker concussive device was used to make the animal model of cerebral concussion in SD rats.The rats were randomly divided into four groups:sham injury group,concussion group,naloxone treatment group and sulpiride treatment group.Spatial learning and memory abilities were evaluated with a series of tasks to find a hidden platform in Morris Water Maze on day 8-13 after concussion.The number of hippocampal CA3 pyramidal cells was counted after Nissl staining.Laser scanning confocal microscope and Fluo-3 were used to measure intracellular cMcium fluorescence pixel values of the hippocampus CA3 pyramidal cells.Results The escape latencies in concussion group were statistically longer thml that in other three groups respectively (P<0.01),with no significant differences between the three groups.The number of crosslng the former site between other three groups.The number of hippocampal CA3 pyramidal cells in concussion group(49.8±1.7),naloxone group(57.3±1.5)and sulpiride group(54.8±1.7)was significantly less than that in sham group(62.7±3.4)respectively(P<0.01),and the differences between concussion group and two treatment group,and the difference between sulpiride group and naloxone group was significant(P<0.01).The fluorescence pixel value of intracellular calcium of hippocampus CA3 pyramidal ceHs in concussion group [(3.0±0.6)×106]was significantly increased compared with other groups[sham group(1.0±0.3)×106,naloxone group(0.9±0.4)×106,sulpiride group(1.1±0.3)×106]respectively(P<0.01),with no significant differences between other three groups.Conclusion The rats spatial learning and memory deficits following cel:cerebral concussion may be related to the reduced number of hippocampus CA3 pyramidal.Apoptosis mechanism may account for the selective loss of hippocampus CA3 pyramidal cells,and both naloxone and sulpiride may be of protective effects.