The Omega-3 Polyunsaturated Fatty Acid Docosahexaenoic Acid (DHA) Reverses Corticosterone-Induced Changes in Cortical Neurons

BACKGROUND Chronic exposure to the glucocorticoid hormone corticosterone exerts cellular stress-induced toxic effects that have been associated with neurodegenerative and psychiatric disorders. Docosahexaenoic acid is a polyunsaturated fatty acid that has been shown to be of benefit in stress-related disorders, putatively through protective action in neurons. METHODS We investigated the protective effect of docosahexaenoic acid against glucocorticoid hormone corticosterone-induced cellular changes in cortical cell cultures containing both astrocytes and neurons. RESULTS We found that glucocorticoid hormone corticosterone (100, 150, 200 μM) at different time points (48 and 72 hours) induced a dose- and time-dependent reduction in cellular viability as assessed by methyl thiazolyl tetrazolium. Moreover, glucocorticoid hormone corticosterone (200 μM, 72 hours) decreased the percentage composition of neurons while increasing the percentage of astrocytes as assessed by βIII-tubulin and glial fibrillary acidic protein immunostaining, respectively. In contrast, docosahexaenoic acid treatment (6 μM) increased docosahexaenoic acid content and attenuated glucocorticoid hormone corticosterone (200 μM)-induced cell death (72 hours) in cortical cultures. This translates into a capacity for docosahexaenoic acid to prevent neuronal death as well as astrocyte overgrowth following chronic exposure to glucocorticoid hormone corticosterone. Furthermore, docosahexaenoic acid (6 μM) reversed glucocorticoid hormone corticosterone-induced neuronal apoptosis as assessed by terminal deoxynucleotidyl transferase-mediated nick-end labeling and attenuated glucocorticoid hormone corticosterone-induced reductions in brain derived neurotrophic factor mRNA expression in these cultures. Finally, docosahexaenoic acid inhibited glucocorticoid hormone corticosterone-induced downregulation of glucocorticoid receptor expression on βIII- tubulin-positive neurons. CONCLUSIONS This work supports the view that docosahexaenoic acid may be beneficial in ameliorating stress-related cellular changes in the brain and may be of value in psychiatric disorders.