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Chen G, Zhang Y, Li R, Jin L, Hao K, Rong J, Duan H, Du Y, Yao L, Xiang D, Liu Z. Environmental enrichment attenuates depressive-like behavior in maternal rats by inhibiting neuroinflammation and apoptosis and promoting neuroplasticity. Neurobiol Stress 2024; 30:100624. [PMID: 38524250 PMCID: PMC10958482 DOI: 10.1016/j.ynstr.2024.100624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 02/25/2024] [Accepted: 03/10/2024] [Indexed: 03/26/2024] Open
Abstract
Gestational stress can exacerbate postpartum depression (PPD), for which treatment options remain limited. Environmental enrichment (EE) may be a therapeutic intervention for neuropsychiatric disorders, including depression, but the specific mechanisms by which EE might impact PPD remain unknown. Here we examined the behavioral, molecular, and cellular impact of EE in a stable PPD model in rats developed through maternal separation (MS). Maternal rats subjected to MS developed depression-like behavior and cognitive dysfunction together with evidence of significant neuroinflammation including microglia activation, neuronal apoptosis, and impaired synaptic plasticity. Expanding the duration of EE to throughout pregnancy and lactation, we observed an EE-associated reversal of MS-induced depressive phenotypes, inhibition of neuroinflammation and neuronal apoptosis, and improvement in synaptic plasticity in maternal rats. Thus, EE effectively alleviates neuroinflammation, neuronal apoptosis, damage to synaptic plasticity, and consequent depression-like behavior in mother rats experiencing MS-induced PPD, paving the way for new preventive and therapeutic strategies for PPD.
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Affiliation(s)
- Guopeng Chen
- Department of Psychiatry, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Yuhui Zhang
- Department of Psychiatry, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Ruiling Li
- Department of Psychiatry, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Liuyin Jin
- Department of Psychiatry, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Keke Hao
- Department of Psychiatry, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Jingtong Rong
- Department of Psychiatry, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Hao Duan
- Department of Psychiatry, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Yiwei Du
- Department of Psychiatry, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Lihua Yao
- Department of Psychiatry, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Dan Xiang
- Department of Psychiatry, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Zhongchun Liu
- Department of Psychiatry, Renmin Hospital of Wuhan University, Wuhan, 430060, China
- Taikang Center for Life and Medical Sciences, Wuhan University, Wuhan, 430071, China
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Dandi E, Kesidou E, Simeonidou C, Spandou E, Grigoriadis N, Tata DA. Sex-Specific Differences and the Role of Environmental Enrichment in the Expression of Hippocampal CB 1 Receptors following Chronic Unpredictable Stress. Brain Sci 2024; 14:357. [PMID: 38672009 PMCID: PMC11047861 DOI: 10.3390/brainsci14040357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Revised: 03/28/2024] [Accepted: 04/01/2024] [Indexed: 04/28/2024] Open
Abstract
Stress-related mental disorders have become increasingly prevalent, thus endangering mental health worldwide. Exploring stress-associated brain alterations is vital for understanding the possible neurobiological mechanisms underlying these changes. Based on existing evidence, the brain endogenous cannabinoid system (ECS) plays a significant role in the stress response, and disruptions in its function are associated with the neurobiology of various stress-related disorders. This study primarily focuses on investigating the impact of chronic unpredictable stress (CUS) on the expression of hippocampal cannabinoid type 1 (CB1) receptors, part of the ECS, in adult male and female Wistar rats. Additionally, it explores whether environmental enrichment (EE) initiated during adolescence could mitigate the CUS-associated alterations in CB1 expression. Wistar rats, shortly after weaning, were placed in either standard housing (SH) or EE conditions for a duration of 10 weeks. On postnatal day 66, specific subgroups of SH or EE animals underwent a 4-week CUS protocol. Western blot (WB) analysis was conducted in the whole hippocampus of the left brain hemisphere to assess total CB1 protein expression, while immunohistochemistry (IHC) was performed on the right hemisphere to estimate the expression of CB1 receptors in certain hippocampal areas (i.e., CA1, CA3 and dentate gyrus-DG). The WB analysis revealed no statistically significant differences in total CB1 protein levels among the groups; however, reduced CB1 expression was found in specific hippocampal sub-regions using IHC. Specifically, CUS significantly decreased CB1 receptor expression in the CA1 and DG of both sexes, whereas in CA3 the CUS-associated decrease was limited to SH males. Interestingly, EE housing proved protective against these reductions. These findings suggest a region and sex-specific endocannabinoid response to chronic stress, emphasizing the role of positive early experiences in the protection of the adolescent brain against adverse conditions later in life.
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Affiliation(s)
- Evgenia Dandi
- Laboratory of Cognitive Neuroscience, School of Psychology, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece;
| | - Evangelia Kesidou
- Laboratory of Experimental Neurology and Neuroimmunology, 2nd Department of Neurology, AHEPA University Hospital, Aristotle University of Thessaloniki, 54636 Thessaloniki, Greece; (E.K.); (N.G.)
- Laboratory of Physiology, School of Medicine, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece; (C.S.); (E.S.)
| | - Constantina Simeonidou
- Laboratory of Physiology, School of Medicine, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece; (C.S.); (E.S.)
| | - Evangelia Spandou
- Laboratory of Physiology, School of Medicine, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece; (C.S.); (E.S.)
| | - Nikolaos Grigoriadis
- Laboratory of Experimental Neurology and Neuroimmunology, 2nd Department of Neurology, AHEPA University Hospital, Aristotle University of Thessaloniki, 54636 Thessaloniki, Greece; (E.K.); (N.G.)
| | - Despina A. Tata
- Laboratory of Cognitive Neuroscience, School of Psychology, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece;
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Somelar-Duracz K, Jürgenson M, Viil J, Zharkovsky A, Jaako K. 'Unpredictable chronic mild stress does not exacerbate memory impairment or altered neuronal and glial plasticity in the hippocampus of middle-aged vitamin D deficient mice'. Eur J Neurosci 2024; 59:1696-1722. [PMID: 38269959 DOI: 10.1111/ejn.16256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 12/10/2023] [Accepted: 01/02/2024] [Indexed: 01/26/2024]
Abstract
Vitamin D deficiency is a worldwide health concern, especially in the elderly population. Much remains unknown about the relationship between vitamin D deficiency (VDD), stress-induced cognitive dysfunctions and depressive-like behaviour. In this study, 4-month-old male C57Bl/6J mice were fed with control or vitamin D free diet for 6 months, followed by unpredictable chronic stress (UCMS) for 8 weeks. VDD induced cognitive impairment and reduced grooming behaviour, but did not induce depressive-like behaviour. While UCMS in vitamin D sufficient mice induced expected depressive-like phenotype and impairments in the contextual fear memory, chronic stress did not manifest as an additional risk factor for memory impairments and depressive-like behaviour in VDD mice. In fact, UCMS restored self-care behaviour in VDD mice. At the histopathological level, VDD mice exhibited cell loss in the granule cell layer, reduced survival of newly generated cells, accompanied with an increased number of apoptotic cells and alterations in glial morphology in the hippocampus; however, these effects were not exacerbated by UCMS. Interestingly, UCMS reversed VDD induced loss of microglial cells. Moreover, tyrosine hydroxylase levels decreased in the striatum of VDD mice, but not in stressed VDD mice. These findings indicate that long-term VDD in adulthood impairs cognition but does not augment behavioural response to UCMS in middle-aged mice. While VDD caused cell loss and altered glial response in the DG of the hippocampus, these effects were not exacerbated by UCMS and could contribute to mechanisms regulating altered stress response.
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Affiliation(s)
- Kelli Somelar-Duracz
- Institute of Biomedicine and Translational Medicine, Department of Pharmacology, University of Tartu, Tartu, Estonia
| | - Monika Jürgenson
- Institute of Biomedicine and Translational Medicine, Department of Pharmacology, University of Tartu, Tartu, Estonia
| | - Janeli Viil
- Institute of Biomedicine and Translational Medicine, Department of Pharmacology, University of Tartu, Tartu, Estonia
| | - Alexander Zharkovsky
- Institute of Biomedicine and Translational Medicine, Department of Pharmacology, University of Tartu, Tartu, Estonia
| | - Külli Jaako
- Institute of Biomedicine and Translational Medicine, Department of Pharmacology, University of Tartu, Tartu, Estonia
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