β-淀粉样蛋白_(25-35)杏仁核注射对大鼠空间学习记忆及海马突触素表达的影响

Influence of unilateral amyloid-β_(25-35) injections into the amygdala on the spatial learning and memory ability and the expression of synaptophysin in hippocampus of rats

目的探讨β-淀粉样蛋白_(25-35)(Aβ_(25-35))杏仁核注射所造痴呆模型大鼠海马突触素的改变及其与空间学习记忆力的关系。方法雄性 Sprague-Dawley 大鼠24只,随机分为正常对照组、假手术组(颅内注射5.0 nmol 0.1%三氟乙酸)、痴呆模型组(颅内注射5.0 nmol AB_(25-35)),每组各8只。采用杏仁核注射 Aβ_(25-35)的方法建立大鼠痴呆模型;通过 Morris 水迷宫测试观察大鼠空间学习记忆能力的改变;应用免疫组织化学染色测定模型大鼠海马突触素表达的水平。结果大鼠痴呆模型建立6周后,痴呆模型组大鼠存在明显的空间学习记忆力障碍,为期6 d 水迷宫测试的平均潜伏期均明显长于正常对照组及假手术组,其中第4～6天与正常对照组的差异有统计学意义(P<0.01)。免疫组织化学染色,痴呆模型组大鼠海马突触素表达的阳性数及着色密度均明显少于正常对照组及假手术组,其中与正常对照组的差异均有统计学意义(P 均<0.01)。结论 Aβ_(25-35)杏仁核注射所造痴呆模型的大鼠海马突触数量明显减少,其空间学习记忆力功能障碍可能与突触的减少有关。

Objective To explore the relationship between the expression of synaptophysin （SYN） in hippocampus and cognitive function in dementia model rats. Methods The dementia rat model was made by unilateral Aβ25-35 injecting into the amygdala. The spatial learning and memory ability were observed by means of Morris water maze experiment, The protein expression of SYN was estimated with immunohistocbemistry. Results The results of Morris water maze indicated that both spatial learning and memory ability in model group rats were impaired seriously compared with the control group rats. The positive cell numbers and optical density of SYN in hippocampus of the model group rats decreased remarkably, Conclusion The synapses reduction in hippocampus is probably related to the impairment of spatial learning and memory in dementia model rats.