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青少期应激对成年小鼠情绪行为的影响及其脑内自噬反应特征
Alternative TitleAdolecent stress inducecd emotional behavior in adult mice and its characteristics of brain autophagy response
任凤燕
Contributor王玮文
2021-06
Abstract发育早期敏感时间窗应激显著增加后期情绪障碍的发病风险。 自噬过程是机体维持细胞稳态的基本反应途径之一在正常脑发育、应激反应调节中发挥重要作用。 近期的临床和基础实验证据显示,情绪障碍患者和模型动物存在自噬反应异常。自噬是否以及如何影响早期应激诱导的情绪障碍疾病的易感性增加目前尚不清楚。 青少期是情绪障碍高发和易感的阶段,而社会应激事件是重要的诱发因素。本研究采用已建立的小鼠青少期社会挫败应激范式 及成年期 10min 强迫游泳的二次应激范式来探讨: 1 )青少期应激对成年动物的基础情绪行为和二次应激所致情绪异常行为易感性的影响 2) 青少期应激对成年动物情绪相关脑区自噬反应的影响; 3) 脑内自噬反应异常与青少期应激诱导的情绪行为改变间的关系。研究首先采用表征快感缺失行为的糖水偏好测试、反映社交兴趣的三箱社交行为测试和表征无助行为的强迫游泳测试 来评估 抑郁样行为;以旷场和高架 十字迷宫测试结果作为焦虑行为的评估指标;以社会回避测试的结果作为经历相关的恐惧行为的评估指标。其次通过 Western blot 方法检测以内侧前额叶 medial Prefrontal cortex mPFC 和皮层下边缘脑区(海马 、杏仁核、伏隔核 与下丘脑为核心的情绪相关脑区内自噬相关分子的表达水平,分别选择自噬上游蛋白Beclin-1、定位在自噬小体双层膜的LC3II蛋白和标志自噬底物降解情况的p62蛋白作为监测完整自噬流的分子指标。 研究 结果: 1) 在行为学水平,与对照组相比,基础状态下经历青少期应激的成年小鼠表现出明显的社会回避行为,社会交往兴趣下降,而其焦虑行为无显著变化。成年期经历二次应激后 ,有早期创伤经历的动物在旷场中表现出显著的焦虑样行为,提示二次应激诱导的焦虑易感 性增高 2) 在情绪相关脑区的分子表达水平上,早期应激组动物在成年期基础状态下海马 的自噬相关分子 LC3II表达显著低于对照组动物而在其他所检测脑区,包括 mPFC 、杏仁核、伏隔核、下丘脑 ,两组动物的自噬分子表达均无显著差异。在经历二次应激后与对照组动物相比,早期应激组 动物海马区的 LC3II 表达显著升高, mPFC 的 LC3II 和Beclin- 1 蛋白表达量则显著降低 ,其余脑区(杏仁核 、伏隔核与下丘脑 的自噬相关蛋白分子表达量无显著差异 ,提示青少期应激诱导了特异性脑区的自噬活动改变 。 3 相关分析结果表明,恐惧行为与 二次应激后 mPFC 自噬活动水平呈显著负相关 ,而与海马区的自噬活动水平呈显著正相关 ;社交兴趣与 mPFC 自噬活动水平呈显著正相关。二次应激后,动物在旷场中的焦虑行为与 mPFC 脑区的LC3II 蛋白表达量的相关性呈边缘显著 。 研究结论: 情绪调节的特异性脑区的自噬活动可能参与了青少期社会应激对成年动物情绪行为的持续影响,为进一步研究自噬过程在早期应激诱导的情绪障碍易感性增高中的作用提供了新的研究证据。
Other AbstractStress in the early stage of development, especially in early adolescence, has a long term impact on the brain and behaviors so that increases the risk of mood disorders significantly. Autophagy is one of the basic functions to maintain cell homeostasis, which plays an important role in brain development and stress responses.Recent clinical and experimental evidence has shown that patients who suffered from mood disorders and relevant model animals had abnormal autophagy responses, but its role in the pathogenesis of psychopathology and its correlation with specific symptomatic phenotypes are still unclear. Whether and how autophagy influences the susceptibility to early stress induced disease is not understood yet. Adolescence is a high incidence and sensitive period for kinds of mood disorders. While social stress is an important predisposing factor for mood disorders. The established adolescent social stress paradigm and adult forced swimming stress were carried out in the investigation of 1) basal emotional behaviors and susceptibility to subsequent stress at adulthood; 2) brain basal autophagy activity and response to subsequent stress; 3) relationship between emotional behavior and autophagy responses inner brain. Sucrose preference test, three chambers social behavior test, and forced swimming test were conducted to evaluate depressive behavior. Open field tests and eleva ted plus maze tests were perform ed to assess anxiety behavior. The social avoidance test was used as an indicator of experience related fear behavior. Weste rn blot experiments were carri e d out to detect the expression levels of autophagy-related proteins in emotion-related brain regions, including the medial Prefrontal cortex (mPFC) and subcortical limbic regions (hippocampus, amygdala, nucleus accumbens, and hypothalamus). The upstream autophagy protein Beclin-1, LC3II protein which is located in the membranes of the autophagosome, and the autophagy substrate degradation marker p62 were chosen as the biomarkers of autophagy flow. Results: 1) Adolescent social defeat stress stably induced fear behavior and decreased interest in social interaction in adult mice, but no significant changes in anxiety behaviors at baseline. Adult animals which experienced adolescent social defeat stress behaved more anxious in open field test after the second hit, suggesting susceptibility to secondary stress. 2) In the stress group, the expression of LC3II in the hippocampus decreased in the basal state of adult mice, indicating a lower autophagic level. While it expressed the opposite trend after the second hi t. The expression levels of LC3II and Beclin 1 in the medial prefrontal cortex were decreased after secondary stress, indicating decreased autophagy levels. However, there were no significant changes in the expression of autophagy related proteins in the a mygdala, nucleus accumbens and hypothalamus. 3) Correlation analysis suggested fear behavior was negatively correlated with autophagy activity in the medial prefrontal cortex and positively correlated with autophagy activity in the hippocampus after second ary stress. There was a significant positive correlation between social interest and medial prefrontal autophagy activity. There was a marginal correlation between animal anxiety behaviors in the open field and LC3II protein expression in mPFC after the se condary stress. Conclusion: In this study, we found autophagy activity changes in the emotion regulating brain region may be involved in the long lasting effect of adolescent social stress on adulthood emotional behavior, which provides new evidence to fur ther study the role of autophagy in early stress induced susceptibility to mood disorders.
Keyword青少期社会应激 恐惧 焦虑 抑郁 自噬 二次应激
Subtype硕士
Language中文
Degree Name理学硕士
Degree Discipline健康心理学
Degree Grantor中国科学院心理研究所
Place of Conferral中国科学院心理研究所
Document Type学位论文
Identifierhttp://ir.psych.ac.cn/handle/311026/39573
Collection健康与遗传心理学研究室
Recommended Citation
GB/T 7714
任凤燕. 青少期应激对成年小鼠情绪行为的影响及其脑内自噬反应特征[D]. 中国科学院心理研究所. 中国科学院心理研究所,2021.
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