Cytokine levels in rat blood and brain structures after administration of lipopolysaccharide.

We compared cytokine profile of rat serum and brain structures after immune status modulation by LPS (30 μg/kg intraperitoneally). The content of inflammatory (IL-1α, IL-1β, IL-2, IL-6, IFN-γ, and TNF-α) and anti-inflammatory (IL-4 and IL-10) cytokines in biological samples of animals was measured on days 1 and 7 after antigenic stimulation. LPS administration reduced the levels of both inflammatory and anti-inflammatory cytokines in the peripheral blood of the rats, especially on the 1st day. LPS administration was also accompanied by specific changes in cytokine content in the dorsal hippocampus and anterior cingulate cortex. Antigenic stimulation increased the level of anti-inflammatory cytokines IL-4 and IL-10 in the examined brain tissues, the changes were most pronounced on day 1 after LPS injection. No significant changes in the levels of proinflammatory cytokines in the brain tissue of animals were found at the above terms after LPS injection. Thus, peripheral LPS administration to rats shifts the balance between the inflammatory and anti-inflammatory cytokines in the CNS structures towards the latter.