中国神经再生研究(英文版) ›› 2020, Vol. 15 ›› Issue (6): 1150-1159.doi: 10.4103/1673-5374.270414

• 原著:脑损伤修复保护与再生 • 上一篇    下一篇

慢性不可预测轻度应激诱导抑郁模型大鼠行为学、齿状回神经发生和海马miR-124的动态变化

  

  • 出版日期:2020-06-15 发布日期:2020-07-05
  • 基金资助:
    国家自然科学基金(81573858);广东省自然科学基金(2016A030313648);广东省教育委员会重大基础研究项目(2017KZDXM020)

Dynamic changes of behaviors, dentate gyrus neurogenesis and hippocampal miR-124 expression in rats with depression induced by chronic unpredictable mild stress

Yun-Ling Huang1, Ning-Xi Zeng1, Jie Chen1, Jie Niu1, Wu-Long Luo1 , Ping Liu2 , Can Yan1 , Li-Li Wu1   

  1. 1 Research Center for Basic Integrative Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong Province, China
    2 Department of Pharmacology, PLA General Hospital, Beijing, China
  • Online:2020-06-15 Published:2020-07-05
  • Contact: Li-Li Wu, PhD,wulili@gzucm.edu.cn; Can Yan, PhD,yc1970@gzucm.edu.cn.
  • Supported by:
    This study was supported by the National Natural Science Foundation of China, No. 81573858 (to LLW); the Natural Science Foundation of Guangdong Province of China, No. 2016A030313648 (to CY); and the Major Basic Research Project of Educational Commission of Guangdong Province of China, No. 2017KZDXM020 (to CY).

摘要:

在抑郁症的病理机制研究和抗抑郁治疗中,抑郁样行为表型、齿状回区神经发生和海马miR-124是目前研究的关注点。实验旨在了解慢性应激致抑郁的过程中,抑郁样行为,齿状回区神经发生及海马区miR-124的动态变化,揭示抑郁症的不同发病阶段具有的不同病理变化,进而为临床抑郁症的治疗策略提供线索。(1)将SD大鼠暴露在各种轻度应激源(包括白噪音、热水游泳、频闪、湿笼、新侵入者、冰水游泳、夹尾、束缚、禁水及禁食等)中建立慢性不可预计轻度应激(CUMS)抑郁症模型,造模过程中与正常组大鼠(正常喂养)进行1-8周动态观察对比;(2)为观察CUMS诱导抑郁过程中抑郁样行为表型的变化,采用糖水偏爱实验检测快感缺失程度,采用旷场实验检测自发活动情况及焦虑情况,发现模型组大鼠在造模第1-4周,虽出现体质量下降,但是无抑郁样行为表型的出现,造模第5-8周,出现了糖水偏爱度降低(快感缺失)和自发活动减少的行为学表型特征,造模1-8周,未见其出现焦虑症状;(3)为观察CUMS诱导抑郁过程中齿状回区神经发生情况及神经元数目改变,采用免疫荧光染色观察大鼠齿状回区神经增殖分化标志物(DCX、DCX/BrdU)双标及神经元标志物(NeuN)的变化发现,与正常组比较,模型组大鼠海马神经发生在造模第2-6周海马齿状回区未见无神经元数目的下降,造模第7-8周,海马齿状回区出现神经增殖分化障碍、神经元数目降低;(4)为观察CUMS诱导抑郁过程中海马miR-124表达的变化,采用qRT-PCR、荧光原位杂交检测发现,与正常组比较,模型组大鼠海马区miR-124的表达在造模1-4周无变化,造模5-6周海马区miR-124的表达升高,造模7-8周海马区miR-124含量降低;(5)以上结果提示,在CUMS诱导的抑郁的过程中,抑郁样行为表型、海马区miR-124表达、海马齿状回区神经发生与神经元数目均呈现动态变化,提示在抑郁症发病的不同阶段具有不同的病理改变。

orcid: 0000-0002-3643-9010 (Li-Li Wu)

         0000-0003-0680-5099 (Can Yan)

关键词: 慢性不可预测轻度应激模型, 抑郁症, 抑郁样行为, 海马, 神经发生障碍, 神经元减少, miR-124, 动态变化, 连续观察

Abstract: The depression-like behavior phenotype, neurogenesis in the dentate gyrus and miR-124 expression in the hippocampus are the focus of current research on the pathogenesis of depression and antidepressant therapy. The present study aimed to clarify the dynamic changes of depression-like behavior, dentate gyrus neurogenesis and hippocampal miR-124 expression during depression induced by chronic stress to reveal pathological features at different stages of depression and to further provide insight into depression treatment. Chronic unpre- dictable mild stress depression models were established by exposing Sprague-Dawley rats to various mild stressors, including white noise, thermal swimming, stroboscopic illumination, soiled cages, pairing with three other stressed animals, cold swimming, tail pinch, restraint and water and food deprivation. Chronic unpredictable mild stress model rats underwent dynamic observation from 1 to 8 weeks and were compared with a control group (normal feeding without any stressors). To observe changes in the depression-like behavior phenotype during chronic unpredictable mild stress-induced depression, a sucrose preference test was used to evaluate the degree of anhedonia. An open-field test was used to evaluate locomotor activity and anxiety status. Compared with the control group, chronic unpredictable mild stress rats lost weight but did not have a depression-like behavioral phenotype at 1–4 weeks. Chronic unpredictable mild stress rats pre- sented decreased sucrose preference and locomotor activity at 5–8 weeks. In addition, chronic unpredictable mild stress rats did not have significant anxiety-like behavior during 1–8 weeks of modeling. To observe neurogenesis dysfunctions and changes in neuronal number in the dentate gyrus during chronic unpredictable mild stress-induced depression, markers (DCX and DCX/BrdU) of neural proliferation and differentiation and the neuronal marker NeuN were assessed by immunofluorescence. Compared with the control group, neurogen- esis and the neuronal number in the dentate gyrus did not change from 2 to 6 weeks; however, neural proliferation and differentiation in the dentate gyrus decreased, and the number of neurons decreased until the eighth week in the chronic unpredictable mild stress group. Real-time quantitative reverse transcription polymerase chain reaction assays and fluorescence in situ hybridization were used to measure the expression of hippocampal miR-124 during chronic unpredictable mild stress-induced depression. The results showed that the expres- sion of hippocampal miR-124 was unchanged during the first 4 weeks but increased from 5 to 6 weeks and decreased from 7 to 8 weeks compared with the control group. These findings indicate that during chronic unpredictable mild stress-induced depression, the behavioral phenotype, miR-124 expression in the hippocampus, neurogenesis in the dentate gyrus and neuronal numbers showed dynamic changes, which suggested that various pathological changes occur at different stages of depression. All experimental procedures and protocols were approved by the Experimental Animal Ethics Committee of Guangzhou University of Chinese Medicine of China in March 2015.

Key words: chronic unpredictable mild stress model, continuous observation, depression, depression-like behavior, dynamic changes, hippocampus, miR-124, neurogenesis dysfunction, neuronal loss