Adverse childhood experiences (ACEs) increase susceptibility to depression and anxiety disorders in adulthood. This study investigated the potential mechanisms through which ACEs enhance vulnerability Show more
Adverse childhood experiences (ACEs) increase susceptibility to depression and anxiety disorders in adulthood. This study investigated the potential mechanisms through which ACEs enhance vulnerability to depression and anxiety in adulthood, using a novel "two-hit" mouse model by combining maternal separation (MS) with 14 or 21 days of restraint stress (RS). Behavioral assessments (sucrose preference test, tail suspension test, open field test, elevated zero maze) confirmed depressive- and anxiety-like behaviors in the MS + RS 21d group mice. Neurobiological analyses revealed hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis (elevated serum corticosterone [CORT] and adrenocorticotropic hormone [ACTH]) and dysregulation, characterized by reduced levels of monoamine neurotransmitters (5-hydroxytryptamine [5-HT], 5-hydroxyindoleacetic acid, dopamine, norepinephrine), altered mRNA expression of key genes (e.g., increased ACTH, CRH, SERT; decreased GR, brain-derived neurotrophic factor [BDNF]), and corresponding protein-level changes (e.g., increased 5-HT1AR, CRHRs; decreased BDNF, TrkB). Our findings indicate that the two-hit mouse model, combining MS with a 21-day RS, stably induces depressive- and anxiety-like behaviors in mice. The underlying mechanism may be associated with HPA axis dysfunction, serotonergic system dysregulation, and aberrant BDNF signaling within the prefrontal cortex-amygdala-hypothalamus circuit. Show less
Maternal separation (MS) is a widely used model of early-life stress that induces long-lasting behavioral and neurobiological alterations in offspring. Maternal exercise during pregnancy has been prop Show more
Maternal separation (MS) is a widely used model of early-life stress that induces long-lasting behavioral and neurobiological alterations in offspring. Maternal exercise during pregnancy has been proposed as a non-pharmacological strategy to counteract these adverse effects. Pregnant Wistar rats were assigned to either a sedentary or exercise group, with the exercise group having free access to a running wheel throughout pregnancy. Offspring were divided into four experimental groups: offspring of sedentary mothers without MS (SedMS-), offspring of sedentary mothers with MS (SedMS+), offspring of exercised mothers without MS (ExMS-), and offspring of exercised mothers with MS (ExMS+). Behavioral assessments, conducted in adulthood starting at postnatal day 90 (P90), included the open field, elevated plus maze, forced swim test, and contextual fear conditioning. Morphological analysis of the hippocampus was performed using isotropic fractionation to quantify total neuronal and non-neuronal cells. Epigenetic changes were evaluated through chromatin immunoprecipitation (ChIP) using anti-acetylated histone H3 and H4, followed by amplification of bdnf exons IV and VI. Maternal separation increased depressive-like behavior and impaired hippocampus-dependent memory, effects that were attenuated by maternal exercise. MS also elevated non-neuronal cell numbers and reduced neuronal cells in the hippocampus, whereas prenatal exercise reversed these alterations. No significant group differences were found in histone acetylation at the Bdnf loci examined. Maternal exercise during pregnancy mitigates behavioral and morphological deficits induced by early-life stress, supporting its neuroprotective role in preserving hippocampal integrity and function. Although no significant epigenetic changes were detected, these findings suggest that maternal physical activity may be a promising intervention to mitigate the long-term neurobiological consequences of early-life adversity. Show less