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United States Department of Agriculture

Agricultural Research Service

Research Project: The Effects of Walnuts on Neuronal Communication and Stress Signaling in Aging

Location: Human Nutrition Research Center on Aging

2013 Annual Report


1a.Objectives (from AD-416):
A major focus of this proposal is concerned with the possible beneficial effects of dietary supplementation of antioxidants and anti-inflammatories in reducing the deleterious effects of reactive oxygen species and inflammation when their levels overwhelm the organism’s defense capacities and damage to cellular macromolecules such as lipids, proteins, and DNA occurs. There have been numerous studies in which antioxidants have been examined with respect to reducing the deleterious effects of brain aging, with mixed results. However, our research suggests that the combinations of antioxidant/anti-inflammatory polyphenolics found in fruits and vegetables may show efficacy in aging. Therefore, in the present study we will determine the effects of these supplementations on stress signaling, microglial activation and neurogenesis and correlate these with alterations in behavioral parameters. The effects of these supplementations on neurogenesis and differentiation will be examined using immunocytochemistry, bromodeoxyuridine (BrDU) incorporation in hippocampus obtained from the supplemented behaviorally-assessed animals.


1b.Approach (from AD-416):
We will utilize several techniques (e.g., Western blot analyses and immunocytochemistry) to assess the changes in several markers of phosphorylation that are important in cell communication (e.g., calcium-dependent protein kinase C, PKC; extracellular signal regulated kinases, ERK) and other markers of stress signaling (e.g., p38 MAPK) in vitro in BV-2 cells and in primary hippocampal neurons.


3.Progress Report:

This study was conducted to investigate whether walnuts can reduce stress and inflammation at cellular levels, using two types of brain cells, neurons and microglia. When the brain cells were subjected to stress, protective communication signals were lost, which in most cases leads to the death of brain cells. However, when these cells were treated with walnut extracts rich in good omega-3 fatty acids, there was a protective effect and restoration of cell signals. Some of the individual omega-3 fatty acids also showed protective effects, while others did not. Serum collected from walnut-fed animals, when applied to brain cells grown in culture, rescued the cells from chemically-induced toxicity. This study established the protective effects of walnuts on brain cells, and showed that whole foods may be more effective than individual components.


Last Modified: 9/20/2014
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