α-突触核蛋白A53T转基因小鼠各月龄运动症状和认知功能的改变

Changes in motor symptoms and cognitive function inα-synuclein A53T transgenic mice at different months of age

目的探讨α-突触核蛋白A53T转基因小鼠各月龄运动症状及认知水平的改变及可能的机制。方法选取6月龄α-突触核蛋白A53T转基因小鼠和野生C57/BL6J小鼠,采用旷场、转棒实验观察小鼠的运动功能及情绪反应,用恐惧刺激和新物体识别试验观察小鼠的认知功能,用免疫印迹方法观察出现认知差异后的两组小鼠海马内M1型胆碱能受体的表达水平,采用转录组方法观察两组小鼠海马组织基因表达的差异。结果各行为学实验表明,与野生型小鼠相比,A53T转基因小鼠在12月龄时出现认知功能障碍[新物体识别系数:A53T(36.74±13.33),C57/BL(46.90±6.58),t=-2.368,P=0.027<0.05],且该种现象发生在运动症状之前。免疫印迹法检测显示,A53T转基因小鼠海马区M1型胆碱能受体水平较野生型小鼠相比差异无统计学意义(P=0.537)。转录组学分析结果提示两组间差异基因290种,其中显著性差异的有20种,而A53T小鼠海马显著下调的基因合集中指向抗细胞炎症反应及抗氧化水平。结论A53T转基因小鼠出现认知功能障碍早于运动症状的发生,且时间节点偏晚。转录组测试提示细胞炎性反应及氧化应激损伤可能参与了A53T转基因小鼠早期的认知障碍病理过程。

Objective To investigate the changes in motor symptoms and cognitive levels in α-synuclein A53T transgenic mice at different months of age and possible mechanisms.Methods The α-synuclein A53T transgenic mice and wild C57/BL6J mice,aged 6 months,were selected.The open field test and the rotarod test were used to observe the motor function and emotional response of mice;fear conditioning and the novel object recognition test were used to observe the cognitive function of mice;Western blotting was used to measure the expression level of M1 cholinergic receptor in the hippocampus of the mice in the two groups,and the transcriptome method was used to observe the difference in gene expression in the hippocampus between the two groups.Results Behavioral experiments showed that compared with the wild-type mice,the A53T transgenic mice showed cognitive dysfunction at 12 months of age[novel object recognition test:(36.74±13.33)vs(46.90±6.58),t=-2.368,P=0.027],and this phenomenon occurred before motor symptoms.Western blotting showed that there was no significant difference in the level of M1 cholinergic receptor in the hippocampus between the A53T transgenic mice and the wild-type mice(P=0.537).The transcriptome analysis identified 290 differentially expressed genes between the two groups,among which there were 20 genes with significant difference,and the significantly downregulated gene sets in the hippocampus of A53T mice were mainly involved in anti-cellular inflammatory response and antioxidant level.Conclusion Cognitive dysfunction in A53T transgenic mice occurs earlier than motor symptoms,with a relatively late time node.Transcriptome tests suggest that cellular inflammatory response and oxidative stress injury might be involved in the early pathological process of cognitive impairment in A53T mice.