Strength training during pregnancy influences hippocampal plasticity but not body development in neonatal rats.

OBJECTIVE: To describe the effects of strength exercise practice during pregnancy on the offspring's development parameters: growth and motor performance, hippocampal neuroplasticity, and stress levels. METHODS: Pregnant Wistar rats were divided into two groups: sedentary and exercised rats. Exercised pregnant rats were subjected to a strength training protocol (vertical ladder climbing) throughout the gestational period. Male offspring's body weight, length, and head size were evaluated during the neonatal period (postnatal days [P]2-P21), as well as motor milestones during P0-P8. At P8, a set of male pups were subjected to global hippocampal DNA methylation, hippocampal cell proliferation, and plasma corticosterone concentration. RESULTS: Offspring from trained mothers presented a transient change in body morphometric evaluations, no differences in milestone assessments, enhancement of cell proliferation in the dentate gyrus of the hippocampus, and decreased global hippocampal DNA methylation compared with the offspring from sedentary mothers. Furthermore, strength training during pregnancy did not change the corticosterone concentration of exercised mothers and their offspring. CONCLUSIONS: These data indicate that strength training can protect offspring's development and could impact positively on parameters linked to cognitive function. This study provides a greater understanding of the effects of strength exercise practiced during pregnancy on the offspring's health.

Paternal physical exercise modulates global DNA methylation status in the hippocampus of male rat offspring.

It is widely known that maternal physical exercise is able to induce beneficial improvements in offspring cognition; however, the effects of paternal exercise have not been explored in detail. The present study was designed to evaluate the impact of paternal physical exercise on memory and learning, neuroplasticity and DNA methylation levels in the hippocampus of male offspring. Adult male Wistar rats were divided into two groups: sedentary or exercised fathers. The paternal preconception exercise protocol consisted of treadmill running, 20 minutes daily, 5 consecutive days per week for 22 days, while the mothers were not trained. After mating, paternal sperm was collected for global DNA methylation analysis. At postnatal day 53, the offspring were euthanized, and the hippocampus was dissected to measure cell survival by 5-bromo-2'-deoxiuridine and to determine the expression of synaptophysin, reelin, brain-derived neurotrophic factor and global DNA methylation levels. To measure spatial memory and learning changes in offspring, the Morris water maze paradigm was used. There was an improvement in spatial learning, as well as a significant decrease in hippocampal global DNA methylation levels in the offspring from exercised fathers compared with those from sedentary ones; however, no changes were observed in neuroplasticity biomarkers brain-derived neurotrophic factor, reelin and 5-bromo-2'-deoxiuridine. Finally, the global DNA methylation of paternal sperm was not significantly changed by physical exercise. These results suggest a link between paternal preconception physical activity and cognitive benefit, which may be associated with hippocampal epigenetic programming in male offspring. However, the biological mechanisms of this modulation remain unclear.

Paternal physical exercise demethylates the hippocampal DNA of male pups without modifying the cognitive and physical development.

Maternal exercise is known to have beneficial effects in progeny development, but the influence of paternal exercise on the offspring still unclear. Since spermatogenesis is a continuous process, the father's life experiences can reprogram epigenetic content of the sperm and somehow interfere on offspring phenotype. This study was designed to evaluate the effects of paternal physical exercise on cognitive and physical development and on hippocampal DNA methylation levels of the offspring. Adult male Wistar rats were divided into two groups: sedentary and exercised. The exercise protocol occurred before mating and consisted of treadmill running, 5 consecutive days/week for 8 weeks (20 min/day). The mothers were not trained. The following developmental parameters were examined in male offspring: body growth, physical and cognitive performance, weights of adrenal glands, gonadal fat and hindlimb muscles, BDNF expression and global DNA methylation at the hippocampus. The progeny of trained and sedentary fathers did not differ in relation to physical parameters and performance, spatial memory and BDNF expression. However, paternal exercise promoted a decrease in offspring´s relative gonadal fat weight and a lower percentage of global hippocampal DNA methylation compared to offspring of sedentary fathers. These results pointed to interference of male physical activity at the time of conception on adiposity and hippocampal epigenetic reprogramming of male offspring. The data reinforces that exercise does not harm the descendant's development and emphasize the benefits to include the practice of physical exercise in a healthier lifestyle of the parents. Nevertheless, future studies are necessary and should investigate further the long-effects of epigenetic mechanisms in order to elucidate the father's contribution in fetal programming.