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Beneficial effects of enriched environment on adolescent rats from stressed pregnancies
Giovanni Laviola1, Monica Rea, Sara Morley-Fletcher
1Section of Behavioural Neuroscience, Department of Cell Biology and Neuroscience, Istituto Superiore di Sanita, Viale Regina Elena, 299, I-00161 Roma, Italy. laviola@iss.it
Insights
Prenatal stress in rats impairs behavior and immunity. Enriched housing during adolescence normalized these deficits, improving social behavior, reducing emotionality, and restoring immune function, even against drug-induced immunosuppression.
Area of Science:
- Neuroscience
- Immunology
- Developmental Psychology
Background:
- Prenatal stress can lead to lasting behavioral and immunological dysfunctions in offspring.
- Early life stress impacts neurodevelopment and immune system maturation.
- Understanding interventions for stress-induced deficits is crucial for developmental health.
Purpose of the Study:
- To investigate the efficacy of an enriched environment as an intervention for prenatal stress-induced impairments.
- To assess the impact of enriched housing on behavioral and immunological outcomes in adolescent rats exposed to prenatal stress.
- To determine if environmental enrichment can mitigate the effects of stress on immune responses.
Main Methods:
- Pregnant rats were exposed to restraint stress (PS) during gestation.
- Offspring were housed in either enriched or standard environments during adolescence.
- Behavioral tests, assessment of circulating immune cells (CD4, CD8 T lymphocytes), cytokine levels (IL-1beta, IL-2), and response to immunosuppression (cyclophosphamide) were conducted.
Main Results:
- Prenatal stress led to reduced play behavior, increased emotionality, and suppressed T lymphocyte counts.
- Enriched housing normalized play behavior, reduced emotionality, and improved most immunological parameters in stressed rats.
- Enriched housing also enhanced anti-inflammatory IL-2 production and alleviated cyclophosphamide-induced immune suppression.
Conclusions:
- Adolescent environmental enrichment can effectively counteract behavioral and immunological deficits caused by prenatal stress.
- Enriched housing positively influences immune system regulation and resilience to stress and drug-induced immunosuppression.
- This study provides evidence for environmental interventions as a strategy to mitigate early life stress impacts.
Abstract:
The capacity of an early environmental intervention to normalize the behavioural and immunological dysfunctions produced by a stressed pregnancy was investigated. Pregnant Sprague-Dawley rats underwent three 45-min sessions per day of prenatal restraint stress (PS) on gestation days 11-21, and their offspring were assigned to either an enriched-environment or standard living cages throughout adolescence [postnatal days (pnd) 22-43]. Juvenile rats from stressed pregnancies had a prominent depression of affiliative/playful behaviour and of basal circulating CD4 T lymphocytes, CD8 T lymphocytes and T4/T8 ratio. They also showed increased emotionality and spleen and brain frontal cortex levels of pro-inflammatory interleoukin-1beta (IL-1beta) cytokine. A more marked response to cyclophosphamide (CPA: two 2 mg/kg IP injections) induced immunosuppression was also found in prenatal stressed rats. Enriched housing increased the amount of time adolescent PS rats spent in positive species-typical behaviours (i.e. play behaviour), reduced emotionality and reverted most of immunological alterations. In addition to its effects in PS rats, enriched housing increased anti-inflammatory IL-2 and reduced pro-inflammatory IL-1beta production by activated splenocytes, also producing a marked alleviation of CPA-induced immune depression. In the brain, enriched housing increased IL-1beta values in hypothalamus, while slightly normalizing these values in the frontal cortex from PS rats. This is a first indication that an environmental intervention, such as enriched housing, during adolescence can beneficially affect basal immune parameters and rats response to both early stress and drug-induced immunosuppression.
