Exercise Reverses Specific Age-Related Brain Changes In Mice : ScienceAlert

Regular physical activity can offer major rejuvenating powers, helping people maintain their strength as they age while protecting against disease and injury. As a growing body of research suggests, this includes valuable protection throughout our bodies, including our brains.

According to a new study led by researchers at the University of Queensland in Australia, exercise can slow or even prevent cognitive decline in mice, with a “profound and selective effect” on certain types of brain cells.

In addition to demonstrating such an intriguing phenomenon in another mammal, the new study also sheds light on how this effect is triggered in the brains of physically active mice.

Studies have suggested similar benefits for humans, but many of the mechanisms behind these effects remain poorly understood, the authors of the new study note. Research like this can provide valuable insight into exactly how exercise strengthens the brain.

The researchers examined the effects of exercise and aging on gene expression in specific cell types in the hippocampus, a complex brain structure involved in learning and memory.

Groups of young and old mice aged 3 or 18 months led sedentary or active lives, with the latter exercising via a wheel. Aging affects all types of brain cells, but appears to affect some more than others, says study co-author Jana Vukovic.

“We found that aging significantly changes the gene expression of all cell types in the brain, but has the greatest impact on microglia, which are immune cells in the central nervous system that support brain function “, explain Vukovic, a neuroimmunologist at Biomedical Sciences and the Queensland Brain Institute at the University of Queensland.

These changes are not set in stone, however. According to the study, when older mice exercised, their microglia looked more like those of younger mice.

A snapshot of microglia (green) in the brain of an aging mouse, expanding their cellular processes to monitor and support nerve cell function. (The University of Queensland)

“Our research showed that exercise, in the form of a running wheel for mice, restored the genetic profile of aged microglia to the patterns seen in younger versions of microglial cells,” says Vukovic.

While aging affected other types of brain cells to some extent, exercise caused a more limited antagonistic effect on them, notes lead author Solal Chauquet, of the University’s Institute of Molecular Bioscience. of Queensland.

“Microglia were the only type of brain cells that showed significant reversal of the changes caused by aging,” says Chauquet.

Along with various changes in brain cells caused by aging, older mice also had higher levels of T cells in their hippocampus, the study found.

T cells are white blood cells with big responsibilities in fighting off foreign intruders, but researchers aren’t sure why they were more prevalent in the brains of older mice.

Nevertheless, physical activity has been associated with a decrease in this age-related increase in T cells, suggesting another possible avenue for exercise to counteract the effects of aging.

“Giving mice access to a running wheel prevented or reduced the presence of T cells in the hippocampus, a part of the brain involved in memory and learning, during aging,” says Vukovic. “This shows that exercise reduces a process associated with aging in mice.”

Although a mouse study can only suggest potential benefits for humans, it still performs an important service, Vukovic adds. Future studies could build on findings like these to uncover new insights about our brains, some of which might one day help us escape old age a little longer.

“Our findings in mice provide a platform for research on the human brain and aging,” she says. “Further research could potentially develop therapeutic means to target specific cell types to combat brain aging.”

The study was published in Aging cell.

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