New Zealand researchers have shown for the first time that exercise helps restore stem cell growth and improves behaviour in young mice that suffered damage to the brain induced by a clinically relevant dose of radiation. The researchers believe that these results are also applicable to children who have suffered damage due to radiotherapy of brain tumours.
Children who receive radiation treatment for brain tumours often develop learning and memory problems later in life that may be associated with attention deficits. These symptoms have been linked to radiation-induced damage, which not only kills cancer cells, but also stem cells that reside in the hippocampus, a region essential for proper memory function.
Dr Andrew Naylor, previously at Sahlgrenska Academy in Gothenburg and now at The University of Auckland, has previously studied the effects of physical exercise on stem cells. Together with Sahlgrenska Academy researchers Associate Professor Klas Blomgren, who has studied the consequences of irradiation on brain cells, and Professor Georg Kuhn, a pioneer in the brain stem cell field, the group investigated whether physical training could counteract previously established damage to certain regions of the brain.
The group studied the effects of radiation on the behaviour of young mice, half of which were provided exercise wheels and half who were not. The study demonstrated that irradiated mice showed increased motor activity and altered movement patterns that were normalised if they were allowed to exercise. In addition, the mouse brains contained 50 per cent more stem cells than their non-exercising counterparts. The researchers were also able to determine that newly formed nerve cells in an irradiated brain form fewer extensions, compared to a non-irradiated brain, and pointing in the wrong direction. If the animals were allowed to exercise, the nerve extensions were normalized.
"These results suggest that irradiation-induced damage in children with brain tumours could be reduced if the child under guidance is allowed to do stimulating and fun exercise", says Professor Georg Kuhn.
The research is published online in the Proceedings of the National Academy of Sciences Early Edition