The effect of combined training and play in an enriched environment during pre-pubertal period on hippocampal structure of adult rats

It is important to maintain the structure and function of the brain throughout life. The main important brain developmental processes occur during the critical periods, especially prepuberty. Thus, environmental interventions during this critical period can lead to significant and permanent changes in developing structures such as the hippocampus. Here, the current study investigated the effect of combined training and play in an enriched environment during prepuberty on the hippocampal structure in adult rats. For this purpose, in this longitudinal study, 27 male rats were divided into three groups of combined training, play in an enriched environment, and control. Interventions were performed for three weeks (28-48 postnatal days). Subsequently, all animals were kept in the standard cages without any intervention until adulthood (48-85 postnatal days). After this period, the animals were sacrificed and hippocampal tissues were removed. The Western blotting and Nissl staining methods were used to assess the brainderived neurotrophic factor (BDNF) and the number of cells in the hippocampus, respectively. The results showed that BDNF levels (P<0.0001) and the number of cells in the hippocampus (P<0.05, P<0.001) increased significantly in the groups with training and play in enriched environment. According to the findings of this study, it can be concluded that training interventions such as organized exercise and active play during sensitive developmental periods have strong and long-lasting effects on the hippocampal structure by increasing BDNF expression.