MODULATION OF HIPPOCAMPAL NEUROGENESIS BY BLUEBERRY DIETARY SUPPLEMENTATION
Gemma Casadesus1*, Barbara Shukitt-Hale1, Heather M. Stellwagen2, and James A. Joseph1
1USDA-ARS, Human Nutrition Research Center on Aging at Tufts University, Boston, MA 02111.
2Department of Psychology, Simmons College, 300 The Fenway, Boston, MA 02115
Until recently, it was believed that neurogenesis ceased after the early postnatal period. However, recent data suggests that the adult brain is also capable of growing new neurons, but that this activity declines in senescence, especially in the dentate gyrus. Moreover it appears that this decline parallels age-related changes in spatial learning and memory. Recent research has shown that these age-related declines in spatial learning and memory tasks can be forstalled and reversed by consumption of flavonoid-rich fruits and vegetables, which exhibit antioxidant and anti-inflammatory actions. One possible mechanism by which these fruits and vegetables improve cognitive performance in old rats may be through the modulation of hippocampal neurogenesis. Therefore, the present study was conducted to investigate whether blueberry-(a fruit with high antioxidant properties) diet supplementation would affect hippocampal neurogenesis and whether changes in this process would be correlated with cognitive improvement in aged rats. Nineteen-month-old rats were fed either a diet supplemented with blueberry extract or a control diet for two months and were tested in the radial arm water maze (RAWM), a test of spatial learning and memory. Following behavioral testing, all rats received repeated injections of bromodeoxyuridine (BrdU) (I.P) and were sacrificed 1 day after the last injection to examine proliferation of new cells or 28 days after to observe survival of these cells in the dentate gyrus. Preliminary results indicate that dietary suplementation with bluberries positively modulates hippocampal neurogenesis. Moreover, these findings are correlated to improvements in the RAWM task. Therefore, these data suggest that supplementation with flavonoid-rich fruits and vegetables can ameliorate cognitive perfomance in aged animals, possibly by modulating hippocampal neurogenesis.
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