Environmental Enrichment: A Double-Edged Sword Therapeutic Approach for Autistic-Like Behaviors

Background and Aim : Enrichment of the environment has been suggested as a possible treatment for neurodevelopmental disorders such as autism. Although the benefits of this therapeutic method have been reported in some animal models and human studies, given the unknown pathophysiology of autism as well as a number of conflicting results, the potential for further studies is still open. To date, no results have been reported regarding the effects of environmental enrichment on autism-related behaviors induced by maternal separation in animal models.Methods : In this study, 40 newborn Wistar rats were divided into 4 groups of 10 each. To develop the autism model, pups were separated from the mother for the first 14 days of life for 3 hours daily (9-12 am). In the treated groups, rats were housed in enriched environment from weaning day (PND 21) to the dates of behavioral tests. At adolescence (PND42-50), behavioral tests including direct social interaction, sociability, repetitive behaviors, anxiety behavior, and locomotion were performed on the rats. Plasma BDNF level was also measured by ELISA technique.Results : This study showed that maternal separation leads to autistic-like and anxiety behaviors with elevated plasma BDNF levels (p <0.05). Environmental enrichment was effective in reducing repetitive behaviors induced by maternal separation (p <0.05). But it did not improve impaired social and anxiety behaviorseven decreased social interaction and increased anxiety in control rats (p <0.05). Enriched environment also increased plasma BDNF level in both control and maternal separation groups (p <0.05).Conclusion : Factors such as animal model, genetic background, details of enrichment of environment including periods of treatment, age can affect the quality of the results. Therefore, more extensive studies in this area are needed. But, the important thing is that the response to a treatment is not always the same between individuals. Accordingly, in psychological disorders especially with an unknown etiology such as autism, many aspects must be considered for the indicating suitable therapeutic approach.

Keywords:

Environmental enrichment , Autism , maternal deprivation