Enriched environment during development is protective against lead-induced neurotoxicity

It is known that children of lower socioeconomic status have a disproportionately higher risk of being exposed to lead and have a more negative outcome from that exposure than children who are raised under more fortunate circumstances. Yet, little is known about how environmental factors may influence the injurious effects on the brain of a neurotoxin such as lead. The present study used an animal model of lead poisoning to examine the extent to which different environmental milieus may modify the effects of lead on the developing brain. Young rats were raised in either enriched or impoverished environments and drank either distilled water or water with lead. Lead-exposed rats raised in the impoverished environment had spatial learning deficits and significantly decreased neurotrophic factor gene expression in the hippocampus. In contrast, the animals raised in the enriched environment were significantly protected against the behavioral and neurochemical toxicity of lead. These results demonstrate that impoverished environment may accentuate while enriched environment may ameliorate neurobehavioral and neurochemical toxicity from developmental lead exposure. (C) 2001 Elsevier Science B.V. All rights reserved.