EAT LESS OR EAT BLUEBERRIES: RESTORING HSP70 NEUROPROTECTION IN THE HIPPOCAMPUS OF OLD RATS





R.L. Galli*, D. Bielinski, A. Szprengiel, B.Shukitt-Hale, J.A. Joseph

Dept of Psychology, Simmons College, 300 The Fenway, Boston, MA 02115



With age there are increased levels of, and reduced protective mechanisms against, cellular stresses such as inflammation and oxidative stress. This study investigated whether short-term nutritional supplementation with blueberries might reverse the effect of age on the brain's ability to generate a neuroprotective response to stress. Hippocampal regions from young and old rats fed either a normal control diet or a diet supplemented with blueberry extract for 10 weeks, were subjected to an in vitro inflammatory challenge (LPS) and then examined by western blot for levels of HSP70. Heat shock proteins including HSP70 are produced in response to any stress that creates denatured proteins and can serve as markers of cellular stress. Baseline levels of HSP70 in hippocampal regions were significantly higher in old control diet rats as compared to young control diet rats. This age-related increase in baseline level of HSP70 was reversed by the blueberry diet.

Overproduction of HSP70 in response to an acute stress has been shown to be neuroprotective. Hippocampal HSP70 levels in response to the in vitro LPS challenge were significantly lower in old control diet rats than in young control diet rats. The blueberry diet completely restored the ability of old rat hippocampal cells to respond to an acute in vitro LPS challenge. These results compare favorably with those found in caloric restriction studies. HSP70 is synthesized in vivo in response to a broad range of injurious stimuli and this suggests that short-term nutritional supplementation with blueberries may result in improved protection against a number of pathological processes in the brain. Age-related changes in hippocampal function have been shown to impair learning and memory. We have previously shown that dietary supplementation with blueberries can retard and even reverse age-related deficits in spatial learning and memory. It is possible that HSP70 mediated neuroprotection in hippocampal regions may contribute to these effects.




Key words: Antioxidants, Oxidative Stress, Inflammation, LPS







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