急性酒精中毒合并中度创伤性脑损伤对大鼠海马NOS2表达和学习记忆的影响

Moderate Traumatic Brain Injury Following Acute Alcoholism Affect Rats Study-Memory and NOS2 Expression in Hippocampus

目的:探讨急性酒精中毒合并中度创伤性脑损伤对大鼠海马NOS2表达和学习记忆的影响。方法:健康成年雄性SD大鼠96只,水迷宫训练3天后分为4组:生理盐水组(N组)、急性酒精中毒组(A组)、中度创伤性脑损伤组(T组)和急性酒精中毒合并中度创伤性脑损伤(AT组)。腹腔单注射25%酒精(2.5g/kg),2 h后以重物自由落体击打大鼠头部建立动物模型,存活1、3、5、7、14天。免疫组化方法检测海马CA1区NOS2表达,水迷宫检测大鼠学习记忆。结果:NOS2免疫组化染色发现各实验组阳性细胞数均高于N组。术后1天T组比AT组表达显著增高(P<0.01);术后5天AT组比T组表达增高(P<0.05);术后14天AT组比T组表达显著增高(P<0.05)。水迷宫实验测潜伏期,术后1天AT组比T组延长(P<0.05),术后3天AT组比T组缩短(P<0.05),术后14天AT组比T组显著延长(P<0.01)。结论:大鼠急性酒精中毒合并颅脑外伤后晚期,潜伏期延长,空间位置学习与记忆能力显著下降;在海马CA1区NOS2表达阳性细胞增多,为继发性脑损伤致其表达上调,是酒精急性中毒合并中度颅脑外伤预后欠佳的原因之一。

Objective： To investigate the spatial memory and the expression of hippocampal NOS2 in rat model of acute alcohol intoxication combined with TBI. Methods： After practice in water maze,96 male SD rats were randomly divided into four groups： N group（saline injection）,A group（alcohol injection）,T group（traumatic brain injury and saline injection） and AT group（traumatic brain injury and alcohol injection）. The animal model of acute alcohol intoxication with TBI was established by hitting rat forehead vertically 2hours following injecting of 25% alcohol 2.5 g/kg intraperitoneally. Animals of each group sacrificed at 1,3,5,7,14 days after behavior tests respectively. The spatial memory was tested by Morris-maze. The expression of NOS2 in hippocampus neurons was detected by immunohistochemistry method. Results： All experimental groups exhibit higher expression of NOS2 than that of N control group. NOS2 expression in T group was higher than in AT group at the 1stday after surgery（P〈0.01）. NOS2 expression in AT group was higher than that of T group from 5^thday to 14^th day after surgery（P〈0.05）. In water maze tests,latency in T group was shorter than that in AT group（P〈0.05） in the 1^st and the 14^th day. However,in the 3rdday,latency in NT group was longer than in AT group（P〈0.05）. Conclusions： Acute alcohol intoxication with advanced TBI had long latency in finding the platform,suggesting that capacity of spatial learning and memory was impaired. The increased expression of NOS2 in rat CA1 neurons area of hippocampus may contribute to secondary brain injury,and may be one of the reasons for unfavourable prognosis in later stage.