We all know the extensive benefits of exercise: work out to stave off disease, improve mental acuity, lose weight, reduce stress, and so on. But even with all these benefits, there are still some questions surrounding the molecular causes that underlie them. Epigenetics has been particularly helpful in gaining new insights into the wide range of health benefits of exercise. Recently, a study showed that exercise could epigenetically keep the brain healthy by boosting the production of a protein called brain-derived neurotrophic factor, or BDNF. Now, a short communication published in Behavioural Brain Research suggests that the frequency of working out and one’s age could play a role in the epigenetic impact exercise has on the body.
A team of researchers from Brazil investigated whether exercising for one session or over a period of time impacted epigenetic marks in both young adult and older rats. First, two groups of rats that were 3 and 20-months old exercised on a treadmill daily for 20 minutes over a period of two weeks or just once for 20 minutes. Then, the researchers measured epigenetic changes in the rats’ prefrontal cortices.
The prefrontal cortex is a part of the brain that is associated with higher-order cognitive functions such as working memory, decision-making, and attention. Previous studies have found a connection between exercise, increased global H4 acetylation in the hippocampus, and improved memory. In addition, the hippocampal-prefrontal circuit has been implicated in learning and memory performance in rodents as well as humans. There could potentially be a link between exercise, epigenetics, and improved cognitive processes. In the current study, the team of researchers found that, depending on the age and exercise frequency, the rats’ epigenetic marks were indeed altered. Specifically, they looked at histone modification and various key epigenetic players.
In order to assess global histone H4 levels in the rats’ brains, the researchers used EpiGentek’s Global Histone H4 Acetylation Assay Kit. This kit uses an absorbance-based quantification method in order to measure global H4 acetylation in a variety of mammalian cells. Histone acetylation is an epigenetic modification commonly associated with gene expression. It is defined as the addition of an acetyl group to histone tails.
The researchers found that daily moderate exercise increased H4 acetylation levels in only older rats. This suggests that the epigenetic impacts of exercise may not affect younger individuals in the same manner as older individuals. Although this study does not make any substantial claims or conclusions, the data can help expand our understanding of exercise and perhaps lead to further investigation. Clearly, exercising is beneficial, but this study brings into question whether someone’s age could determine if exercise might epigenetically benefit them more or less.
Additionally, they measured levels of DNMT3B protein with EpiGentek’s EpiQuik Dnmt3B Assay Kit. DNA methyltransferases, or DNMTs, are epigenetic enzymes that catalyze the process of DNA methylation, a mechanism that has previously been connected to the aging process. The level of one particular DNMT, known as DNMT3B, was increased in both young and old rats that only exercised once. However, the amount of this protein wasn’t changed for the animals that participated in daily exercise. They also measured histone methyltransferase H3K27 and DNMT1, but found no significant changes between the rats’ ages or exercising sessions.
These results offer a glimpse into important exercise-induced epigenetic modifications, which could have differing effects on the brain and body depending on age. More research is necessary, but these initial findings open up new opportunities for research in the epigenetic effects of exercise and how different exercise types or duration may impact people of different ages.
Source: Cechinel, L.R., Basso, C.G., Bertoldi, K., Schallenberger, B., de Meireles, L.C., Siqueira, I.R. Treadmill exercise induces age and protocol-dependent epigenetic changes in prefrontal cortex of Wistar rats. Behavioural Brain Research, 313: 87-87.