Concentrations of metabolic hormones and cytokines in the plasma of <i>db/+</i> and <i>db/db</i> mice.

<p>Data represent means ± SEM (n = 6–7/group).</p><p>*<i>p</i><.05,</p><p>**<i>p</i><.01,</p><p>***<i>p</i><.001 for <i>db/db vs. db/+</i> mice.</p

mRNA expression levels of GP130, SOCS3 and BDNF in the hippocampus and hypothalamus.

<p>Relative fold changes in the levels of (A–B) hippocampal and (C–D) hypothalamic GP130, SOCS3 and BDNF mRNA expression, as calculated in relation to the averaged value for control saline group. GP130, glycoprotein 130; SOCS3, suppressor of cytokine signaling-3; BDNF, brain-derived neurotrophic factor. Data represent means ± SEM (n = 6/group). * <i>p</i><.05 for <i>db/db vs. db/+</i> mice.</p

Working memory performances of <i>db/db</i> and <i>db/+</i> mice.

<p>(A) Spatial recognition in the Y-maze expressed as the time spent exploring the novel and the familiar arms. (B) Time spent exploring the novel and the familiar object in the novel object recognition task. In both tasks, measures were assessed over a 5-min test and after 30-min retention. Data represent means ± SEM (n = 7–10/group). * <i>p</i><.05, ** <i>p</i><.01 for <i>db/db vs. db/+</i> mice.</p

mRNA expression levels of cytokines in the hippocampus and hypothalamus of <i>db/db</i> and <i>db/+</i> mice.

<p>Relative fold changes in the levels of (A) hippocampal and (B) hypothalamic IL-1β, TNF-α, IL-6, IFN-γ and MCP-1 mRNA expression, as calculated in relation to the averaged value for control saline group. IL-1β, interleukin-1β; TNF-α, tumor necrosis factor-α; IFN-γ, interferon-γ; MCP-1, monocyte chemotactic protein-1. Data represent means ± SEM (n = 6/group). * <i>p</i><.05 for <i>db/db vs. db/+</i> mice.</p

IL-1β mRNA expression after the exposure to the Y maze in P2X₇R^−/− mice.

<p>IL-1β mRNA was measured by real-time PCR on WT and P2X₇R^−/− mice sacrificed either after free exploration (control group) or completion of behavioral testing (Y-maze group). All data are expressed as mean relative fold change±SEM (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0006006#s2" target="_blank">Materials and Methods</a> for explanation). (A) IL-1β mRNA on hippocampus extracts from the 2-min ITI Y-maze group and their controls (left-hand panel) and the 30-min ITI Y-maze group and their controls (right-hand panel). (B) IL-1β mRNA on hypothalamus extracts from the 30-min ITI Y-maze group and their controls. Y maze exposure significantly increased the IL-1β mRNA expression in the hippocampus of WT mice but not of P2X₇R^−/− mice. Whatever the group considered (WT or P2X₇R^−/−), no induction of IL-1β mRNA expression was detected in hypothalamus after the Y maze experience. ***p<0.001, **p<0.01.</p

Preference for novelty was measured using a 2-min ITI in WT and P2X7R^−/− mice.

<p>Both strain exhibited a clear preferential exploration of the novelty (Arm effect, ***p<0.001).</p

Recognition memory performance after 30 minutes of retention in P2X₇R^−/− mice.

<p>(A) Time spent (sec) in the novel or the familiar arm after a 30-min ITI. (B) Time spent (sec) exploring the novel or the familiar object after a 30-min ITI. Spatial recognition memory, but not object recognition memory, was impaired in P2X₇R^−/− mice after a 30-min ITI. ***p<0.001, **p<0.01,*p<0.05.</p

Spatial and object recognition memory.

<p>(A) Time spent (in sec) in the novel or the familiar arm after a 5-min ITI in 3-month-old (young) and 22-month-old (aged) mice fed with the control diet or the LCω3 diet for 2 months. (B) Time spent (in sec) in the novel or the familiar object after a 1-hr ITI in 3-month-old (young) and 22-month-old (aged) mice fed with the control diet or the LCω3 diet for 2 months. *** p<0.001, ** p<0.01, * p<0.05.</p

c-Fos expression in the DG, CA1 and CA3 regions of the hippocampus.

<p>c-Fos immunohistochemical analysis was performed in the hippocampus of 3-month-old (young) and 22-month-old (aged) mice fed with the control diet or the LCω3 diet for 2 months and sacrificed 90 min after the spatial recognition acquisition session. (A) Representative images of c-Fos immunohistochemistry in the DG (left panel), the CA1 (central panel) and the CA3 region (right panel) of the hippocampus. Scale bar = 100 µm. (B) Quantification of c-Fos-positive cells was performed in the DG, the CA1 and the CA3 regions of the hippocampus. Data are presented as mean ± SEM. ** p<0.01. (C) Correlation between the number of c-Fos positive cells induced by the Y-maze task in the DG (left panel), the CA1 (central panel) and the CA3 (right panel) and the spatial recognition score. Pearson's correlation coefficients (r) and corresponding significance (p) are displayed within each correlation window. The number of c-Fos positive cells in the DG and CA1, but not in the CA3 regions of the hippocampus was positively correlated to the spatial recognition score.</p

Brain fatty acid composition.

<p>dGLA: dihomo-gamma-linolenic acid (20:3 ω6); AA: arachidonic acid (20:4 ω6); EPA: eicosapentaenoic acid (20:5 ω3); DHA: docosahexaenoic acid; DMA: dimethyl acetal; LC ω6: long chain ω6 (20:2 ω6+20:3 ω6+20:4 ω6+22:4 ω6+22:5 ω6); LC ω3: long chain ω3 (20:5 ω3+22:5 ω3+22:6 ω3); NS: not significant.</p>***<p>p<0.001 as compared to aged control diet;</p>**<p>p<0.01 as compared to aged control diet;</p>*<p>p<0.05 as compared to aged control diet.</p