WASHINGTON (Reuters) - Exercise may reverse some damage that radiation does to the brain, Swedish researchers reported on Tuesday in a study that offers a way to help childhood cancer survivors.
Tests on mice showed that those encouraged to exercise had more immature cells known as stem cells in their brains, and that these cells were more likely to develop into neurons, brain cells that do the bulk of the work in the brain.
The findings, published in the Proceedings of the National Academy of Sciences, may provide ways to help pediatric brain cancer survivors who often have learning, memory and attention problems.
Andrew Naylor of the Institute for Neuroscience and Physiology at Sweden’s Goteborg University and colleagues first irradiated the brains of baby mice.
The dose was comparable to doses given cancer patients with brain tumors.
Half of the mice were given a running wheel. The mice allowed to run were more likely to explore and moved more freely than mice merely kept in their cages, the researchers found.
After a few months all the mice were killed and their brains examined.
Mice allowed to run had more precursor cells and more new neurons, and these neurons took up their places better in the brains than mice simply kept in cages, the researchers reported. The mice allowed to exercise had a 275 percent increase in the number of newborn cells that developed into neurons.
“Our work indicates that the functional deficits observed in pediatric patients after radiation therapy are not irreversible and may be amenable to treatment; therefore, exercise should be evaluated in rehabilitation therapy of children after radiotherapy to the brain,” the researchers wrote.
“We believe it is important that a small number of stem cells survive the radiation treatment to participate in the restructuring process,” they added, suggesting that radiologists may want to better shield important parts of the brain while treating young patients with brain tumors.
Reporting by Maggie Fox; Editing by Julie Steenhuysen and Vicki Allen