Beneficial effects of enriched environment on adolescent rats from stressed pregnancies

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.

Sex effects on neurodevelopmental outcomes of innate immune activation during prenatal and neonatal life

“…No other sex or pretreatment differences were observed at other time points (e.g., P70, P400, P600), although previous studies have shown decreased anxiety in P600 males prenatally exposed to acute LPS (Golan et al, 2005(Golan et al, , 2006. Compared to prenatal immune activation by pathogens, other forms of prenatal stressors (such as restraint stress) seem to consistently produce anxiety-like behaviors in both prenatally stressed offspring compared to non-stressed control (Kohman et al, 2008a;Laviola et al, 2004).…”

Adolescence: A central event in shaping stress reactivity

“…That is, the dramatic changes in physiology and neurobehavioral function during adolescence may make an individual extremely susceptible to perturbations (Andersen, 2003;Dahl, 2004), but these striking transitions may also afford an important opportunity to intervene and combat these perturbations. There does appear to be experimental support for this assertion such that exposure to an enriching environment during adolescence can offset many of the negative neurobehavioral and physiological consequences of early life adversity (Bredy, Humpartzoomian, Cain, & Meaney, 2003;Bredy, Zhang, Grant, Diorio, & Meaney, 2004;Francis, Diorio, Plotsky, & Meaney, 2002;Laviola et al, 2004;Morley-Fletcher, Rea, Maccari, & Laviola, 2003), including brain damage (Twiggs, Popolow, & Gerall, 1978). Though it remains to be established whether it is necessary for these interventions to occur during adolescence to be most effective, these data do suggest that a window of opportunity exists for interventions during this crucial period of development.…”

Longitudinal effects of environmental enrichment on behaviour and physiology of pigs reared on an intensive-stock farm

“…There is consolidated evidence to show that the characteristics of the housing environment have a marked influence on the behaviour and welfare of animals, both those raised for biomedical investigation or farm animals (Beattie et al, 2000;Olsen et al, 2002;Laviola et al, 2004;Dong et al, 2007;Brenes et al, 2008). In particular, the provision of straw seems to represent a suitable strategy to alleviate the presence of injurious behaviours in swine (Petersen et al, 1995;Kelly et al, 2000;Guy et al, 2002;Van de Weerd et al, 2006;Studnitz et al, 2007).…”