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.