Environmental enrichment reverts the effects of continuous or intermittent perinatal alcohol exposure. Focus on alcohol vulnerability and affectivity in the offspring

Abstract

Alcohol consumption during perinatal periods is common, despite the warning of adverse effects on the foetal development. In female rats, the intermittent pattern of alcohol consumption is responsible for higher drinking levels and more profound disruption of maternal care than traditional continuous free-access paradigm, which can have persistent effects on the offspring. The environmental enrichment, a powerful form of experience-dependent plasticity that allows high cognitive, motor and sensory stimulations, is helpful for recovering from different neurological pathologies. Thus, this study aimed at exploring the effects of environmental enrichment on alcohol vulnerability and affective behaviour in the offspring that was perinatally exposed to continuous or intermittent alcohol. Dams were given two-bottle choice to water and 20% alcohol with either continuous- or intermittent access (CA vs IA), along a 12-week period. They were alcohol-deprived during breeding and resumed alcohol self-administration from late gestation and throughout lactation. Alcohol-exposed offspring, reared in either standard- or enriched- conditions, were assessed for alcohol drinking behaviour in a free-choice paradigm and were also tested for the deprivation effect. Moreover, they were tested for behavioural reactivity in the open field; anxiety-like behaviour in the elevated plus maze and depressive-like behaviour in the forced swim test during the drinking paradigm. Our results show that perinatal CA to alcohol did not increase alcohol-drinking behaviour with respect to controls. On the other hand, rats perinatally exposed to IA displayed a high vulnerability to alcohol, in terms of drinking behaviour and deprivation effect. The environmental enrichment was able to exert a protective role on alcohol vulnerability in perinatally IA exposed rats and controls, especially during relapse. Moreover, it was able to induce an increase in behavioural reactivity in the open field and a decrease in anxiety-like behaviour in the elevated plus maze, in both perinatally CA and IA exposed groups. In conclusion, the pattern of alcohol consumption during pregnancy and lactation can influence long-term alcohol vulnerability in the offspring. Rearing conditions that promote high cognitive, motor and sensory stimulations improve resilience to alcohol abuse and affective tone, although they cannot be sufficient to full recovery from detrimental effects of perinatal alcohol exposure.