Submitted to: Neurobiology of Aging
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/31/2005
Publication Date: 2/1/2006
Citation: Galli, R.L., Bielinski, D.F., Szprengiel, A., Shukitt Hale, B., Joseph, J.A. 2006. Blueberry supplemented diet reverses age-related decline in hippocampal hsp70 neuroprotection. Neurobiology of Aging 27 (2006)344-350. Interpretive Summary: Blueberries have been shown to have anti-aging effects when fed to rats. When old rats were fed a normal diet supplemented with blueberries they made fewer mistakes learning their way around a maze, and remembered the maze better, than old rats that didn't get blueberries. The new experiments reported in this article looked at what the blueberry diet might be doing in the brain to explain the remarkable the improvements in memory. One way that brain cells can protect themselves from the effects of age is by producing a protein called Heat Shock Protein 70 (HSP 70). HSP 70 can work like a maintenance crew to repair the kind of damage caused to the cells of the brain during normal aging. The results of our research show that old rats typically don't make as much HSP 70 when it is needed as do young rats. Perhaps more importantly, we found that old rats fed a blueberry supplemented diet can make lots of HSP 70, just like the young rats do. In fact, this improved ability to make HSP 70 was seen in cells from a part of the rat brain important in learning and memory. Because HSP 70 works to repair the kind of damage that occurs with age, these results may help explain why blueberries work so well to prevent age-related declines in learning and memory.
Technical Abstract: Dietary supplementation with fruits can ameliorate age-related oxidative stress and deficits in neuronal and behavioral functions. We examined whether short term supplementation with blueberries might enhance the brain's ability to generate an HSP70 mediated neuroprotective response to stress. Hippocampal regions from young and old rats fed either a control or a supplemented diet for 10 weeks were subjected to an in vitro inflammatory challenge (LPS) and then examined for levels of HSP70 by immunoblot. Baseline levels of HSP70, indicative of chronic neurotoxicity, were significantly higher in old control diet animals as compared to young control diet rats; however, this age-related increase in baseline level of HSP70 was reversed by the blueberry diet. Increases in HSP70 in response to an acute LPS challenge were significantly less in old as compared to young control diet rats; the blueberry diet completely restored the ability to respond to the LPS challenge in the old rats. Induction of HSP70 in response to an acute stressor has been demonstrated to be neuroprotective in a variety of paradigms. This suggests that a short-term nutritional intervention may result in improved HSP70-mediated protection against a number of neurodegenerative processes in the brain.