Exercise reverses age-related neural stem cell decline

Recent study results have revealed that exercise can reverse the age-related decline in the production of neural stem cells that occurs in the brain of mice by increasing levels of a growth factor known to promote neuronal stem cell differentiation and survival.

Previous research has showed that the production of stem cells in the hippocampus declines dramatically before mice reach middle-age and that exercise can reverse this decline, however how it does so remained uncertain. To try and ascertain exactly how exercise reverses this age-related decline Yu-Min Kuo and colleagues trained young, adult, early middle-aged, middle-aged, and old mice to run on a treadmill for up to one hour each day for five-weeks. Throughout the study the researchers measured the effect of exercise on the production of neural stem cells, serum corticosterone levels, and brain-derived neurotrophic factor (BDNF) and its receptor TrkB levels in the hippocampus.

As the researchers expected, results showed that the production of neural stem cells declined markedly in middle-age. However, the results also showed that the production of new neural stem cells was approximately 200% higher in mice that exercised in comparison with mice that did not. Furthermore, the survival rate of new nerve cells increased by 170% and their growth increased by 190%. Exercise also increased neural stem cell production in young mice.

Results also showed that levels of BDNF and its receptor TrkB in the hippocampus of mice that exercised were significantly higher than those found in sedentary mice, thus suggesting that exercise reverses the age-related decline in neural stem cell production by increasing levels of BDNF.

Wu CW, Chang YT, Yu L, Chen HI, Jen CJ, Wu SY, Lo CP, Kuo YM. Exercise enhances the proliferation of neural stem cells and neurite growth and survival of neuronal progenitor cells in dentate gyrus of middle-aged mice. J Appl Physiol. 2008;105:1585-1594.

News release: Exercise increases brain growth factor and receptors, prevents stem cell drop in middle age. American Physiological Society. November 18th 2008.