Elsevier

Neuroscience Research

Volume 171, October 2021, Pages 124-132
Neuroscience Research

Sleep disturbance induces depressive behaviors and neuroinflammation by altering the circadian oscillations of clock genes in rats

https://doi.org/10.1016/j.neures.2021.03.006Get rights and content

Highlights

  • Sleep deprivation (SD) for 3 days induces anxiety and depressive-like behaviors in rats.

  • SD alters the circadian oscillations of clock genes in the hypothalamus.

  • SD alters the expression of BBB tight junction protein and disrupts BBB integrity.

  • Neuroinflammation is involved in SD-induced changes in neuropathology and behaviors.

Abstract

Sleep loss leads to a spectrum of mood disorders such as anxiety disorders, bipolar disorder and depression in many individuals. However, the underlying mechanisms are largely unknown. In this study, sleep-disturbed animals were tested for anxiety and depressive behaviors. We then studied the effects of SD on hypothalamic-pituitary-adrenal (HPA) axis function by measuring serum and CSF levels of corticosterone (CORT), and at the end of the experiment, brains were collected to measure the circadian oscillations of clock genes expression in the hypothalamus, glial cell activation and inflammatory cytokine alterations. Our results indicated that SD for 3 days resulted in anxiety- and depressive-like behaviors. SD exaggerated cortisol response to HPA axis, significantly altered the circadian oscillations of clock genes, decreased the expression of tight junction protein ZO-1 and Claudin 5 and increased the number of GFAP-positive cells and Iba-1-positive cells and caused subsequent elevation of pro-inflammatory cytokines IL-6, IL-1β and TNFα. These findings demonstrated that SD for 3 days induced anxiety- and depression-like behaviors in rats in company with altering the circadian oscillations of clock genes and inducing neuroinflammation, indicating the underlying mechanism of sleep loss induced neuronal dysfunction.

Introduction

Sleep, as a physiological phenomenon, has been found to play important roles in the functioning of the nervous, muscular and immune systems, leading to accentuated growth and rejuvenation (Bass and Takahashi, 2010; Ferguson et al., 2016). A lack of sleep is a common problem in modern society, and it has severe consequences for health and results in related neurological disorders that consume a large fraction of health care resources. Sleep loss has a profound, negative impact on cognition, learning, mood, and diverse aspects of mental health. Despite decades of research, the reasons why sleep loss negatively impacts brain function have remained unclear.

Circadian rhythms, defined as oscillations with a period of 24 h, are a fundamental component of mammalian physiology. Sleep is clearly regulated by the circadian clock, as human sleep patterns follow clear circadian patterns. Mammalian circadian rhythms are regulated by a molecular transcription/translation feedback loop involving transcriptional inhibitory proteins (PER1, PER2, CRY1, and CRY2) and transcriptional activating proteins (BMAL1, CLOCK, and NPAS2) (Ho et al., 2018; Kayaba et al., 2017; Lauretti et al., 2017; Pan and Rickard, 2015). The deletion of the master clock geneBMAL1 abrogates all circadian function, leading to a total loss of the day-night rhythmicity of sleep and massive astrocyte activation and inflammation (Laposky et al., 2005; Li et al., 2013; Ratajczak et al., 2009). Circadian rhythm impairments occur in many mental disorders such as depression (Bhattacharjee, 2007), manic disorders (Yin et al., 2006; Toh et al., 2001). Patients with major depressive disorder (MDD) presented with disruptions in biological circadian rhythms (Kronfeld-Schor and Einat, 2012). However, how these disruptions cause homeostatic imbalances in neurological diseases remains poorly understood.

Circadian rhythm dysfunction has been associated with inflammation in the periphery, but the role of the circadian clock genes in neuroinflammation remains poorly understood. Neuroinflammation is widely regarded as inflammation of the central nervous system, which includes microglia activation and increases in the levels of pro-inflammatory cytokines in the brain, and may lead to cognitive function decline (Aguirre, 2016; Rasch and Born, 2013). Various clinical studies have also documented the occurrence of inflammation caused by sleep loss (Siegel, 2005). Recent studies have provided evidence that both chronic sleep loss and fragmentation can activate glial cell types and influence behavioral and physiological states (Graves, 2003; Ho et al., 2018; Wisor et al., 2008). In addition, the activation of the sympathetic nervous system and HPA axis after sleep disturbance leads to a heightened pro-inflammatory state. However, the exact neuropathological mechanism underlying sleep loss induced neuronal dysfunction is not fully understood.

The present study aimed to investigate whether sleep loss triggers anxiety- and depressive-like behaviors accompanied by the disruption the circadian oscillations of clock genes, the activation of inflammatory mediators with reactive astrogliosis and microgliosis in rats. Rats were first subjected to behavioral tests after 3 days of sleep disturbance (SD) to evaluate emotional impairment. Then, we examined the pathological events associated with neuroinflammation, such as the activation status of microglia and astrocytes as well as the expression of pro-inflammatory cytokines. We also demonstrated the underlying mechanisms of SD-associated neurobehavioral alterations, the effects of SD on the HPA axis function and the mRNA profile of circadian oscillations of clock genes in the hypothalamus. Our results demonstrated that the impact of SD on depression and highlighted the importance of neuroinflammation in adapting to sleep loss. One mechanism through which SD may contribute to depressive symptomatology is by affecting the circadian oscillations of clock genes and ultimately causing circadian rhythm dysfunction.

Section snippets

Animal

Adult male Sprague-Dawley rats (200–220 g) were purchased from Vital River Laboratory Animal Technology Co. (Beijing, China). Animals were maintained under a 12 h light/12 h dark cycle. Food and water were available ad libitum. Temperature was maintained between 22 °C and 24 °C and lights were on at 7:00 A.M. and off at 7:00 P.M. Zeitgeber time (ZT) 0 is here defined as lights on, corresponding to 7:00 A.M.

Sleep disturbance protocol

Rat was subjected to a treadmill cage (l × w × h = 50.8 cm × 16.51 cm × 30.48 cm, Beijing

SD increases locomotor activity and anxiety behavior in rats

The experiments were performed as shown in Fig. 1A. After 3 days of sleep disturbance, rats were tested for novelty-induced locomotor activity in the open field, the elevated plus maze to assess anxiety-like behavior. In the OF test, the total distance traveled were increased especially the time spent in the center area was obviously increased in SD rats (Fig. 1B and C) indicating SD increased exploratory activity in rats. In the EPM test, there is no difference of total entrance to the open

Discussion

In the present study, we used an animal model of sleep disturbance that mimics chronically insufficient sleep as it often occurs in humans. We found that sleep disturbance leads to behavioral abnormalities, including increased anxiety and depressive-like behaviors. Sleep disturbance alters the transcript profile of circadian clock genes and induces proinflammatory cytokines, which regulates physical, mental, and behavioral changes in several pathological processes. These observations indicate a

Conclusions

Taken together, the results of the present study show that consistent sleep loss is able to change emotional behavior and psychopathology in rats. SD induced neuroinflammation by altering the circadian oscillations of clock genes and inducing microglial pro-inflammatory cytokines, and it resulted in the progressive breakdown of the BBB integrity. With the high prevalence of anxiety and depression in society, animal models of sleep disturbance that result in anxiety and depressive-like

Authors contribution

Xing Chen: Performed research, Analyzed data; Yanzhao Zhou: Performed research, Analyzed data; Xuan Xu: Contributed new reagents or analytic tools;Mengnan Ding: Contributed new reagents or analytic tools; Yifan Zhang: Analyzed data; Min Zhang: Analyzed data; Meiru Hu: Contributed new reagents or analytic tools; Xin Huang: Designed research, Performed research, Analyzed data, Wrote the paper; Lun Song: Contributed new reagents or analytic tools, Analyzed data, Revised the paper.

Funding

This work was supported by grants from the Natural Science Foundation of China, nos. 81430044 and 81700759, The Major Project of Logistics Scientific Research of PLA, China (grant No. AWS17J014, BWS17J025) to Dr. Lun Song.

Ethics approval and consent to participate

All procedures performed in studies involving animals were in accordance with the ethical standards of the institutional research committee. Rats were maintained at the animal facility with free access to water and food in accordance with institutional guidelines. The Institutional Animal Care and Use Committee (IACUC) of the Academy of Military Medical Sciences approved all experiments involving rat.

Consent for publication

Not applicable.

Availability of data and materials

Authors make readily reproducible materials described in this manuscript, including all relevant raw data, freely available to any scientist wishing to use them, without breaching participant confidentiality.

Declaration of Competing Interest

The authors report no declarations of interest.

Acknowledgments

We would like to thank Prof. Ningsheng Shao for the contributing to the data analysis of qPCR. Dr. Liming Zhang is acknowledged for extending the Morris water maze facility for the study.

References (39)

  • C.C. Aguirre

    Sleep deprivation: a mind-body approach

    Curr. Opin. Pulm. Med.

    (2016)
  • R. Arantes et al.

    A novel anxiety index for the rat behavior in the elevated plus-maze

    BMC Neurosci.

    (2013)
  • J. Bass et al.

    Circadian integration of metabolism and energetics

    Science (New York, NY)

    (2010)
  • M. Bellesi et al.

    Sleep loss promotes astrocytic phagocytosis and microglial activation in mouse cerebral cortex

    J. Neurosci.

    (2017)
  • Y. Bhattacharjee

    Psychiatric research. Is internal timing key to mental health?

    Science

    (2007)
  • V. Castagne et al.

    Rodent models of depression: forced swim and tail suspension behavioral despair tests in rats and mice

    Curr. Protoc. Neurosci.

    (2011)
  • L. Eckel-Mahan Kristin et al.

    Reprogramming of the circadian clock by nutritional challenge

    Cell

    (2013)
  • D.L. Feinstein et al.

    Causes, consequences, and cures for neuroinflammation mediated via the locus coeruleus: noradrenergic signaling system

    J. Neurochem.

    (2016)
  • X. Feng et al.

    Anxiolytic effect of increased NREM sleep after acute social defeat stress in mice

    Neurosci. Bull.

    (2020)
  • Cited by (13)

    • A broken circadian clock: The emerging neuro-immune link connecting depression to cancer

      2022, Brain, Behavior, and Immunity - Health
      Citation Excerpt :

      This is related to elevations in neuro-inflammatory IL-1β and IL-6 in the hippocampus (Norden et al., 2015). Sleep disturbances in cancer patients are prevalent (Palesh et al., 2010), and such disturbances induce depressive behaviors by disrupting clock gene expression and clock controlled pro-inflammatory cytokines like IL-6, IL-1β and TNFα (Xing et al., 2021). As such, cancer is likely to promote depression by regulating circadian clock driven inflammatory states.

    • Dendrobium officinale polysaccharide attenuates cognitive impairment in circadian rhythm disruption mice model by modulating gut microbiota

      2022, International Journal of Biological Macromolecules
      Citation Excerpt :

      Disruptions of circadian rhythm have negative consequences for metabolic syndrome, obesity, increased risk of cancer, as well as other physiological and mental disorders. Chronobiology researchers discovered that the body's circadian rhythms were regulated by circadian clock genes, may be involved in the development of cognitive function in mice [49]. In our previous research, we found that the circadian clock gene of Clock, showed lower expression level in CD mice than the normal group, exhibiting the disruptions of circadian rhythm [16].

    View all citing articles on Scopus
    1

    These authors contribute equally to this work.

    View full text