Fig. 6

Effects of hippocampal exogenous IL-33 on spatial memory and habituation and hippocampi mRNA expression in IL-1αβ KO mice. IL-1αβ KO mice were intrahippocampally injected with rmIL-33 or vehicle solution (PBS-BSA 0.1%). Habituation in a novel environment was analyzed in intrasession (a) and in intersession 24 h and 48 h post-surgery (b). mRNA expression of pro-inflammatory markers (Nos2 in c, Il1b in d, Tnfa in e, and Ifng in f) or anti-inflammatory markers (Arg1 in g, Chil3 in h, Il10 in i, and Igf1 in j) was quantified by RT-qPCR normalized against 18S RNA at 48 h post-administration in WT/sham (WT-S), IL-1αβ KO/sham, IL-1αβ KO/vehicle and IL-1αβ KO/rmIL-33-treated groups (n = 4–6). Relative fold change in groups was quantified versus WT/sham group (S; white bar). Data are shown as mean ± SEM. The habituation analysis (a, b), n = 8–10 per group corresponding to a pool of 2 independent experiments. Two-way ANOVA followed by a Sidak post hoc test was used to analyze the distance traveled among the two groups (IL-1αβ KO injected with vehicle or rmIL-33). For qPCR analysis, statistical comparisons were made using Kruskal-Wallis followed by Dunn’s multiple comparison test for each group vs. WT/Sham. *P ≤ 0.05, **P ≤ 0.01, ***P ≤ 0.001