title: Early adversity contributes to chronic stress induced depression-like behavior in adolescent male rhesus monkeys.
abstract: Chronic stress is an important cause for depression. However, not everyone who is exposed to chronic stress will develop depression. Our previous studies demonstrated that early adversity can cause lasting changes in adolescent rhesus monkeys, but depressive symptoms have not been observed. Compared to adults, it is still unknown that whether adolescent rhesus monkeys experiencing early adversity are more likely to develop depressive symptoms. In this study, we investigated the long term relationship between early adversity, chronic stress and adolescent depression for the first time. Eight male rhesus monkeys were reared in maternal separation (MS) or mother-reared (MR) conditions. All of them went through unpredictable chronic stress for two months at their age four. The stressors included space restriction, intimidation, long illumination and fasting. Behavioral and physiological data were collected during the experiment. The results showed that, compared with the MR group, the locomotor activity of MS group was significantly decreased after one month of chronic stress while huddling up and stereotypical behaviors were significantly increased. Moreover, this trend continued and even worsened at the second month. Significantly higher hair cortisol levels and lower body weight were observed in MS group after two months of stress. These results indicate that early adversity is one of the environmental factors which can increase the susceptibility of depression when experiencing chronic stress in the later life. This will further clarify the important roles of early environmental factors in the development of adolescent depression and children rearing conditions should receive more attention.
authors.affiliation: Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China; University of the Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Zhi-Yi
authors.initials: ZY
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China; Center for Drug Safety Evaluation, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China; Kunming Primate Research Center, Chinese Academy of Sciences, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Mao
authors.affiliation: Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China.
authors.forename: Xiao-Li
authors.initials: XL
authors.lastname: Feng
authors.affiliation: Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China; University of the Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Na
authors.initials: N
authors.lastname: Zheng
authors.affiliation: Kunming Primate Research Center, Chinese Academy of Sciences, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China.
authors.forename: Long-Bao
authors.initials: LB
authors.lastname: Lü
authors.affiliation: Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China.
authors.forename: Yuan-Ye
authors.initials: YY
authors.lastname: Ma
authors.affiliation: Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China. Electronic address: qindong108@163.com.
authors.forename: Dong-Dong
authors.initials: DD
authors.lastname: Qin
authors.affiliation: Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China; CAS Center for Excellence in Brain Science, Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China. Electronic address: xthu@mail.kiz.ac.cn.
authors.forename: Xin-Tian
authors.initials: XT
authors.lastname: Hu
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001835:Body Weight; D003863:Depression / Q000209:etiology*; D004195:Disease Models, Animal; D006197:Hair / Q000737:chemistry; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism; D008124:Locomotion / Q000502:physiology; D008253:Macaca mulatta; D008297:Male; D008426:Maternal Deprivation; D011897:Random Allocation; D020018:Sexual Dysfunctions, Psychological / Q000209:etiology; D013239:Stereotyped Behavior / Q000502:physiology; D013315:Stress, Psychological / Q000150:complications* / Q000209:etiology*
chemical_list: D006854:Hydrocortisone
keywords: Chronic unpredictable stress; Cortisol; Depression; Early adversity; Monkeys