Fig. 3.

Pro-inflammatory cytokines expression in the hypothalamus of TLR2- and TLR4-deficient mice after NA injection. The mRNA levels of IL-1β (a), TNFα (b), and IL-6 (c) was measured by qPCR in hypothalamic tissue from WT, TLR2^-/-, and TLR4^-/- mice obtained 6 h after the ICV injection of saline or NA. mRNA levels of the target genes were expressed relative to the expression level of GAPDH using the Pfaffl method. The injection of NA induced the overexpression of the three cytokines in WT mice and in TLR2^-/- mice, the increase being milder in the latter strain. However, in TLR4^-/- mice injected with NA, the expression levels of the three cytokines were similar to those on saline controls. The histograms show means + SD of n = 3 saline injected and n = 5 NA-injected animals of each strain. Two-way ANOVA was used to compare the means of the groups. Letters (a–c) on top of the bars indicate the absence (same letter) or presence (different letter) of a significant difference (P < 0.05) between groups