Apoptotic changes in the aged brain are triggered by interleukin-1β-induced activation of p38 and reversed by treatment with eicosapentaenoic acid

Abstract

Among the several changes that occur in the aged brain is an increase in the concentration of the proinflammatory cytokine interleukin-1β that is coupled with a deterioration in cell function. This study investigated the possibility that treatment with the polyunsaturated fatty acid eicosapentaenoic acid might prevent interleukin-1β-induced deterioration in neuronal function. Assessment of four markers of apoptotic cell death, cytochrome c translocation, caspase-3 activation, poly(ADP-ribose) polymerase cleavage, and terminal dUTP nick-end staining, revealed an age-related increase in each of these measures, and the evidence presented indicates that treatment of aged rats with eicosapentaenoate reversed these changes as well as the accompanying increases in interleukin-1β concentration and p38 activation. The data are consistent with the idea that activation of p38 plays a significant role in inducing the changes described since interleukin-1β-induced activation of cytochrome c translocation and caspase-3 activation in cortical tissue in vitro were reversed by the p38 inhibitor SB203580. The age-related increases in interleukin-1β concentration and p38 activation in cortex were mirrored by similar changes in hippocampus. These changes were coupled with an age-related deficit in long term potentiation in perforant path-granule cell synapses, while eicosapentaenoate treatment was associated with reversal of age-related changes in interleukin-1β and p38 and with restoration of long term potentiation.