Early exercise induces long-lasting morphological changes in cortical and hippocampal neurons throughout of a sedentary period of rats

• Published in: Scientific reports Vol. 9; no. 1; pp. 13684 - 11
• Main Authors: Serra, Fernando Tadeu, Carvalho, Andrea Dominguez, Araujo, Bruno Henrique Silva, Torres, Laila Brito, Cardoso, Fabrizio dos Santos, Henrique, Jéssica Salles, Placencia, Eduardo Varejão Díaz, Lent, Roberto, Gomez-Pinilla, Fernando, Arida, Ricardo Mario, Gomes da Silva, Sérgio
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 23.09.2019; Nature Publishing Group
• Subjects: 13/1; 13/51; 14/10; 14/19; 14/35; 631/378/1686; 631/378/2611; 82/80; Adolescents; Adrenocorticotropic Hormone - metabolism; AKT protein; Animals; Brain-derived neurotrophic factor; Brain-Derived Neurotrophic Factor - metabolism; Cell proliferation; Cell Shape - physiology; Cerebral cortex; Cerebral Cortex - cytology; Cerebral Cortex - metabolism; Cerebral Cortex - physiology; Children; Corticosterone - metabolism; Cyclic AMP response element-binding protein; Cytology; Dendrites - physiology; Dendritic branching; Exercise; Hippocampus; Hippocampus - cytology; Hippocampus - metabolism; Hippocampus - physiology; Humanities and Social Sciences; Hypotheses; Male; Morphology; multidisciplinary; Neuronal Plasticity - physiology; Neurons - cytology; Neurons - metabolism; Neurons - physiology; Neurotrophic factors; Physical activity; Physical Conditioning, Animal - physiology; Physical fitness; Physical training; Rats; Rats, Wistar; Rodents; Science; Science (multidisciplinary); Sedentary behavior; TOR protein; TOR Serine-Threonine Kinases - metabolism
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-019-50218-9

Life experiences at early ages, such as physical activity in childhood and adolescence, can result in long-lasting brain effects able to reduce future risk of brain disorders and to enhance lifelong brain functions. However, how early physical exercise promotes these effects remains unclear. A possible hypothesis is that physical exercise increases the expression of neurotrophic factors and stimulates neuronal growth, resulting in a neural reserve to be used at later ages. Basing our study on this hypothesis, we evaluated the absolute number and morphology of neuronal cells, as well as the expression of growth, proliferation and survival proteins (BDNF, Akt, mTOR, p70S6K, ERK and CREB) in the cerebral cortex and hippocampal formation throughout of a sedentary period of rats who were physically active during youth. To do this, male Wistar rats were submitted to an aerobic exercise protocol from the 21 st to the 60 th postnatal days (P21–P60), and evaluated at 0 (P60), 30 (P90) and 60 (P120) days after the last exercise session. Results showed that juvenile exercise increased, and maintained elevated, the number of cortical and hippocampal neuronal cells and dendritic arborization, when evaluated at the above post-exercise ages. Hippocampal BDNF levels and cortical mTOR expression were found to be increased at P60, but were restored to control levels at P90 and P120. Overall, these findings indicate that, despite the short-term effects on growth and survival proteins, early exercise induces long-lasting morphological changes in cortical and hippocampal neurons even during a sedentary period of rats.