Background:There are reports that life experiences at early ages such as physical activity in childhood and adolescence can reduce the future risk of brain disorders and enhance
lifelong brain functions. However how early physical activity promotes such effects are not well understood. A possible explanation is that physical exercise can stimulate neuronal growth, resulting
in a neural reserve which could be extracted throughout the life course. The present study was designed to investigate the hypothesis of neural reserve induced by early physical activity. To do this,
we evaluated the cortical and hippocampal levels of BDNF, ACTH and corticosterone during the aging course of rats submitted to physical exercise during adolescent period.
Methods: Forty-eight male Wistar rats were distributed into exercise (EX, n=24) and control (CTL, n=24) groups. Rats from EX group were submitted to an aerobic exercise program during
the 21st and 60th postnatal day (P21-P60). Afterward, cortical and hippocampal levels of BDNF, ACTH and corticosterone from the EX and CTL groups were investigated at different life stages: 0 (P60),
30 (P90), 60 (P120) and 90 (P150) days after last exercise session. The BDNF, ACTH and corticosterone levels were quantified by mean of Luminex xMAP system (MAGPIX technology).
Results:After the last physical training session (at P60), a significant increase of hippocampal BDNF (p = 0.002) and a decrease of cortical ACTH (p = 0.03) were detected in EX group
in relation to CTL group. At P90, a significant decrease in hippocampal BDNF level was observed in the Ex group when compared to the CTL group (p = 0.016). At P150, levels of hippocampal ACTH (p =
0.003) and cortical corticosterone (p = 0.043) were lower in Ex group than in CTL group.
Conclusions: Our results indicate that changes in the cortical and hippocampal levels of proteins and hormones linked to cellular growth and stress may occur throughout of life of
rats exercised in youth.