The effects of forced training and voluntary physical activity in environmental enrichment on hippocampal structure and function in prepubertal rats.

Oral Presentation
Paper ID : 1163-12THCONG
Oral / Poster Presentation File: 1163-12THCONG.mp4 
Authors
1Exercise Physiology, Faculty of Sport Sciences and Health, Shahid Beheshti University, Thehran, Iran
2Department of Biological Sciences in Sport and Health, Faculty of Sports Sciences and Health, Shahid Beheshti University, Tehran, Iran
3Department of Physiology at Institute of Neuroscience and Physiology,Göteborg, Sweden
Abstract
Childhood is a special period during which training may have different effects. A sensitive period correspond with significant neurodevelopmental processes. The immature neuronal circuitry might be especially sensitive to experiences and thus might be more easily affected compared to mature structures. Hippocampus, a region important for cognitive functioning, can be modulated by experiences. In addition, because the hypothalamo-pituitary-adrenal (HPA) axis continues to develop through childhood, exposure to stress during these formative years may effects on HPA activity and brain. We propose interventions like forced and voluntary physical activity might have differential effects on hippocampus structural and functions. Moreover, physical fitness level may be associated neuro-cognitive benefits.
To evaluate the effects of forced training and voluntary physical activity in environmental enrichment on hippocampal structure and function in prepubertal rats.
At weaning, juvenile male wistar rats (N=27) were divided into three groups: combine training (CT), enviromental enrichment (EE) and control (C). CT was performed on a treadmill and ladder adapted to rats in alternate days while EE consisted of a large cage with ramp and running wheels for voluntary physical activity and objects of different shapes and textures. Interventions began at 21 days and continued until 49 days of age. In 2 days, all rats were subjected to the open field and functional (consist of 1RM, Maximim Speed and Grip Strength) tests. At 52 days, the hippocampus were isolated for protein quantification and nissl staining was conducted to evaluate cell survival.
The results of nissl staining demonstrate that EE prevents death of neuronal cells. In this group, more healthy neurons and less nuclear pyknosis were observed that accordance with decrease anxiety-like behaviors in comparison with the CT. Physical fitness components increased in CT, however grip strength in EE group was significantly greater. No differences in body weight, BMI and food intake were seen.
The results of the present study suggest voluntary physical activity in environmental enrichment likely provides a better stimulation for improving hippocampal structure and function. Although CNS activity-dependent mechanisms are pivotal but peripheral mechanisms are also important.
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