The ability of walnut extract and fatty acids to protect against the deleterious effects of oxidative stress and inflammation in hippocampal cells

Abstract

Previous research from our lab has demonstrated that dietary walnut supplementation protects against age-related cognitive declines in rats; however, the cellular mechanisms by which walnuts and polyunsaturated fatty acids (PUFAs) may affect neuronal health and functioning in aging are undetermined.

Objectives

We assessed if pretreatment of primary hippocampal neurons with walnut extract or PUFAs would protect cells against dopamine- and lipopolysaccharide-mediated cell death and calcium dysregulation.

Methods

Rat primary hippocampal neurons were pretreated with varying concentrations of walnut extract, linoleic acid, alpha-linolenic acid, eicosapentaenoic acid, or docosahexaenoic acid prior to exposure to either dopamine or lipopolysaccharide. Viability was assessed using the Live/Dead Cellular Viability/Cytotoxicity Kit. Also, the ability of the cells to return to baseline calcium levels after depolarization was measured with fluorescent imaging.

Results

Results indicated that walnut extract, alpha-linolenic acid, and docosahexaenoic acid provided significant protection against cell death and calcium dysregulation; the effects were pretreatment concentration dependent and stressor dependent. Linoleic acid and eicosapentaenoic acid were not as effective at protecting hippocampal cells from these insults.

Discussion

Walnut extract and omega-3 fatty acids may protect against age-related cellular dysfunction, but not all PUFAs are equivalent in their beneficial effects.

Keywords:

• Hippocampal cells
• Inflammation
• Omega-3
• Oxidative stress
• Walnut

Acknowledgements

This research was supported by USDA Intramural and the California Walnut Commission. We thank Katharine Luskin and Vivian Cheng for assistance in completing the experiments. Also, we thank Dr Lauren Willis for preparation of the walnut extract.