A cross-sectional comparison of ethanol-related cytokine expression in the hippocampus of young and aged Fischer 344 rats.

Our work in Sprague Dawley rats has shown rapid alterations in neuroimmune gene expression (RANGE) in the hippocampus and paraventricular nucleus of the hypothalamus (PVN). These manifest as increased interleukin (IL)-6 and IκBα, and suppressed IL-1β and tumor necrosis factor alpha during acute ethanol intoxication. The present studies tested these effects across the lifespan (young adulthood at 2-3 months; senescence at 18 and 24 months), as well as across strain (Fischer 344) and sex. The hippocampus revealed age-dependent shifts in cytokine expression (IL-6, IL-1β, and monocyte chemoattractant protein 1), but no changes were observed in the PVN at baseline or following ethanol. RANGE in adults was similar across sex and comparable with effects seen in Sprague Dawley rats. Plasma corticosterone levels increased with age, whereas the blood ethanol concentrations and loss of righting reflex were similar in all groups older than 2 months. These findings indicate that the RANGE effect is largely conserved across strain and is durable across age, even in the face of a shifting neuroimmune profile that emerges during immunosenescence.