Effects of spermidine on pro-inflammatory cytokine production in LPS-stimulated BV2 microglia. Cells were pretreated with the indicated concentrations of spermidine for 1 h before LPS treatment. Following incubation for 24 h, the supernatants were analyzed for IL-6 (A) and TNF-α (B) content. Each value indicates the mean ± S.D. of three independent experiments. *P < 0.05 indicates a significant difference from cells treated with LPS in the absence of spermidine.