Astrocytic plasticity at the dorsal dentate gyrus on an animal model of recurrent depression. (1st February 2021)

• Record Type: Journal Article
• Authors: Machado-Santos, Ana R.; Alves, Nuno D.; Araújo, Bruna; Correia, Joana S.; Patrício, Patrícia; Mateus-Pinheiro, António; Loureiro-Campos, Eduardo; Bessa, João M.; Sousa, Nuno; Pinto, Luísa
• Is Part Of: Neuroscience. Volume 454(2021)
• Page Start: 94
• Page End: 104
• Publication Date: 2021-02-01
• Subjects: ADs antidepressants -- DG dentate gyrus -- FLX fluoxetine -- GCL granule cell layer -- GFAP glial-fibrillary acid protein -- MDD major depressive disorder -- SAL saline -- SGZ subgranular zone -- uCMS unpredictable chronic mild stress; Astrocytes -- Dentate gyrus -- Chronic stress -- Recurrent depression -- Antidepressants; Neurochemistry -- Periodicals; Neurophysiology -- Periodicals; Neurology -- Periodicals; Neurochimie -- Périodiques; Neurophysiologie -- Périodiques; Neurochemistry; Neurophysiology; Electronic journals; Periodicals; Electronic journals; 612.8
• DOI: 10.1016/j.neuroscience.2019.10.032
• Languages: English
• ISSNs: 0306-4522

Abstract

Highlights: Number of astrocytes is increased in the dentate gyrus after stress re-exposure. Antidepressants prevent changes in astrocytic numbers induced by stress re-exposure. Antidepressants promote a decrease of astrocytic complexity after stress exposure. Antidepressants induce astrocytic complexity restoration after stress re-exposure. Abstract: Astrocytes are now known to play crucial roles in the central nervous system, supporting and closely interacting with neurons and therefore able to modulate brain function. Both human postmortem studies in brain samples from patients diagnosed with Major Depressive Disorder and from animal models of depression reported numerical and morphological astrocytic changes specifically in the hippocampus. In particular, these studies revealed significant reductions in glial cell density denoted by a decreased number of S100B-positive cells and a decrease in GFAP expression in several brain regions including the hippocampus. To reveal plastic astrocytic changes in the context of recurrent depression, we longitudinally assessed dynamic astrocytic alterations (gene expression, cell densities and morphologic variations) in the hippocampal dentate gyrus under repeated exposure to unpredictable chronic mild stress (uCMS) and upon treatment with two antidepressants, fluoxetine and imipramine. Both antidepressants decreased astrocytic complexity immediately after stress exposure. Moreover, we show that astrocytic alterations, particularly an increased number of S100B-positive cells, are observed after recurrent stress exposure. Interestingly, these alterations were prevented at the long-term by either fluoxetine or imipramine treatment.