运动对快速老化小鼠海马β-淀粉样蛋白及淀粉样蛋白前体蛋白的影响

目的 研究运动对快速老化小鼠(SAMP)8海马β-淀粉样蛋白(Aβ)及淀粉样蛋白前体蛋白(APP)的影响,以探讨运动改善阿尔茨海默病(AD)学习记忆功能的机制.方法 将40只3月龄SAMP8小鼠采用单纯随机抽样法分为运动组和对照组,运动组进行跑笼运动训练,第1个月每周训练5 d,每天10 min,第2个月每周训练5 d,每天20 min.2个月后采用H-E染色观察2组小鼠海马神经元形态改变;免疫组织化学技术检测海马Aβ免疫阳性细胞的表达;逆转录-聚合酶链反应(RT-PCR)技术检测海马APP mRNA的表达水平.结果 对照组5月龄SAMP8小鼠海马部分神经元细胞变性、死亡,核浓缩,空泡变性;运动组偶有神经元细胞变性、死亡,大部分细胞形态正常.运动组海马Aβ免疫阳性细胞表达水平为(0.192±0.018),明显低于对照组的(0.274±0.017)(P＜0.05);运动组海马APP mRNA表达水平为(0.168±0.059),明显低于对照组的(0.574±0.115)(P＜0.01).结论 运动可以延缓SAMP8小鼠海马神经元变性,降低海马Aβ及APP的表达,这可能是运动改善AD学习记忆功能的重要机制之一.

Abstract：

Objective To explore the effects of movement on hippocampal β-amyloid protein ( Aβ ) and amyloid precursor protein (APP) in senescence-accelerated and senescence-prone (SAMP8) mice, and the mechanism by which movement improves learning and memory in mice with a model of Alzheimer's disease. Methods Forty 3-month-old SAMP8 mice were divided randomly into a movement group and a control group. The movement group was trained with a running wheel 10 min daily, 5 days a week in the first month, and 20 min daily in the second month. Morphological changes in the hippocampus were observed under the microscope after HE staining. The expression of Aβ in the hippocampus was detected by immumohistochemical methods and APP mRNA expression was detected by RT-PCR two months later. Results HE staining showed neuron degeneration and death, chromatin condensation and vacuolar degeneration in the hippocampus of the 5-mouth-old SAMP8 mice of the control group. The movement group showed less neuron degeneration and death, and the morphology of most cells was normal The expression of Aβ in the hippocampus of the 5-month-old SAMP8 mice in the movement group was significantly lower than that in the control group. APP mRNA expression levels in the movement group were also significantly lower.Conclusions Movement can delay neuron degeneration and down-regulate Aβ and APP mRNA expression levels in the hippocampus of SAMP8 mice. It may be an important mechanism by which movement improves learning and memory in mice with a model of Alzheimer's disease.