Environmental enrichment prevents cognitive Impairment and improves stress. Reactivity in prenatally-stressed Mice.

LR GUELMAN; MA ZORRILLA ZUBILETE; MARIANO ENRIQUE RAMBORGER; ACOSTA GB

Cancún

Congreso; 6th International Symposium on Metabolic Programming and Microbiome and the 3rd Meeting of Ibero-American DOHaD chapter.; 2018

Metabolic Programming and Microbiome and the 3rd Meeting of Ibero-American DOHaD chapter.

The stress suffered by a mother during pregnancy can induce adverse effects on the offspring, such as cognitive impairments, alterations in thehypothalamic?pituitary?adrenal (HPA) axis and the stress response, and an increased vulnerability to the development of behavioral disorders later in life. Previous studies suggest that this effect may be sex-dependent. Researchin animals has shown that early environmental enrichment (EE),a housing condition enriched with tactile, visual and social stimuli, increases hippocampal neurogenesis, and improves both spatial memory and stress reactivity. Our aim is to assess the efficacy of an early EE treatment in preventing or preventing the deleterious effects of Prenatal (PS) Stress on Balb/C mice.Methods and ResultsPregnant dams were divided into Control (C) and PS groups. The latter were subjected to restraint stress 2h/d, from PD14 until delivery. Offspring was weaned at PN21, and subjects from both groups were then randomly assigned to either Standard Housing cages or EE ones, resulting in four groups. At PN90, animals underwent behavioral testing, using a battery comprised of an Open field test, and an Object in Place (OIP) task. PS animals presented a significant increase in anxiety-related behaviorsin the Open Field when compared to controls, with an increase in locomotion, but a decrease in the time spent exploring the center of the arena. This difference was not present in the PS+EE group. PS subjects also displayed an impairment in contextual-spatial memory. EE housing significantly prevented this effect, with PS+EE animals OIP score being more similar to their EE counterparts.After behavioral testing, animals were sacrificedand hippocampus (Hic) samples were collected. PS animals presented a significant increase in hippocampal Glucocorticoid Receptors (GR), hinting at an HPA-axis alteration. This increase was not found in PS+EE animals, whose levels were more similar the control group. ConclusionsPS mice showed a clear impairment on spatial memory. While a tendency regarding sex-differences was observed, the impact of prenatal stress on the Object-In-Place was not significantly different in males and females. Results in PS+EE mice suggest that an EE treatment can revert the effects of PS in contextual spatial memory. The increase of stress-related behaviors in the Open Field, such as rearing and center-avoidance, suggests that PS increased stress reactivity.This is supported by the increase in GR in PS animals, which may imply an alteration of the HPA-axis regulation. PS¬+EE animals were again more similar to control and EE animals, suggesting that EE can prevent some of the negative effects of PS, both at neurochemical and behavioral levels.