Environmental Enrichment Rescues Oxidative Stress and Behavioral Impairments Induced by Maternal Care Deprivation: Sex- and Developmental-Dependent Differences

Starting maternal exercise, unlike reducing the intensity of exercise during pregnancy, prevents memory deficits in female offspring subject to maternal deprivation

Maternal deprivation (MD) leads to long-lasting memory deficits. Conversely, maternal exercise could potently modify the offspring's cellular machinery. Here, we tested whether starting to run or reducing the intensity of running during pregnancy can protect prepubertal female offspring against MD-induced memory deficits. Female rats were divided into different groups submitted or not to MD: one started to run before pregnancy and reduced the intensity during the pregnancy (PGE); another started to run at the beginning of pregnancy (GE); and, finally, a control group (CT) was not submitted to exercise. All the rats but those of the CT ran on a treadmill until the delivery day (PND 0). Subsequently, MD was performed from PND 1 to 10. We assessed object recognition (OR) and spatial memory (SM) of female offspring after weaning (PND22, pre-pubertal stage). MD caused OR memory deficit; GE female offspring did not present this deficit, but PGE did. Both PGE and GE alone enhanced offspring spatial learning, but their combination with MD impaired it. MD promoted hippocampal lipid peroxidation increase, which both PGE and GE prevented. Total antioxidant capacity in the hippocampus was higher in both MD-exercised groups compared to all others. Although the antioxidant effects of exercise were similar in both MD exercise groups, we observed better results in the memory tests in the GE group than in the PGE group. These results suggest that starting to exercise during pregnancy is better than reducing the exercise intensity during pregnancy to prevent MD-induced memory deficits in female offspring.

Sex differences on the response to antidepressants and psychobiotics following early life stress in rats

Major depressive disorder (MDD) is the most prevalent mood disorder globally. Most antidepressants available for the treatment of MDD increase the concentration of monoamines in the synaptic cleft. However, such drugs have a high latency time to obtain benefits. Thus, new antidepressants with fast action and robust efficacy are very important. This study evaluated the effects of escitalopram, ketamine, and probiotic Bifidobacterium infantis in rats submitted to the maternal deprivation (MD). MD rats received saline, escitalopram, ketamine, or probiotic for 10, 30, or 50 days, depending on the postnatal day (PND):21, 41, and 61. Following behavior, this study examined the integrity of the blood-brain barrier (BBB) and oxidative stress markers. MD induced depressive-like behavior in females with PND21 and males with PND61. All treatments reversed depressive-like behavior in females and escitalopram and ketamine in males. MD induced an increase in the permeability of the BBB, an imbalance between oxidative stress and antioxidant defenses. Treatments regulated the oxidative damage and the integrity of the BBB induced by MD. The treatment with escitalopram, ketamine, or probiotics may prevent behavioral and neurochemical changes associated with MDD, depending on the developmental period and gender.

Olfactory loss is a predisposing factor for depression, while olfactory enrichment is an effective treatment for depression

The loss of olfactory stimulation correlates well with at least 68 widely differing neurological disorders, including depression, and we raise the possibility that this relationship may be causal. That is, it seems possible that olfactory loss makes the brain vulnerable to expressing the symptoms of these neurological disorders, while daily olfactory enrichment may decrease the risk of expressing these symptoms. This situation resembles the cognitive reserve that is thought to protect people with Alzheimer’s neuropathology from expressing the functional deficit in memory through the cumulative effect of intellectual stimulation. These relationships also resemble the functional response of animal models of human neurological disorders to environmental enrichment, wherein the animals continue to have the induced neuropathology, but do not express the symptoms as they do in a standard environment with restricted sensorimotor stimulation.