Figure 2.

The mRNA levels of IL‐1β, IL‐6, TNF‐α, and Neuregulin were affected by age, and the protein levels of IFNγ and TNFα were increased by LPS treatment. The mRNA levels of proinflammatory cytokines IL‐1β (a), IL‐6 (b), and TNFα (c) were elevated in the PI cortical samples of the aged mice compared to young ones. The expression of Neuregulin, a neuronal growth factor showing neuroprotective properties, was significantly reduced in the aged mice compared to young mice (d). The peripheral inflammation did not affect significantly to the expression of these mediators (a‐d). The protein levels of cytokines were measured by CBA kit from plasma samples at 24 h post‐ischemia. Inflammatory cytokine IFNγ (e) was elevated in the group of aged mice with peripheral inflammation, and the concentration correlated significantly with the lesion size (the bigger the lesion, the higher the cytokine concentration) (f). Similar elevated concentration and correlation were also observed with TNFα (g, h). The data are shown as mean ± SD. VEH = Vehicle treatment, LPS = LPS treatment, *p < 0.05 **p < 0.01 ***p < 0.001 (a) F(1, 42) = 14.12 p = 0.0005 age effect of two‐way ANOVA, n = 8–14 (b) F(1, 42) = 7.88 p = 0.0075 age effect of two‐way ANOVA n = 8–14 (c) F(1, 43) = 8.23 p = 0.006 age effect; F(1, 43) = 6.19 p = 0.017 treatment effect of two‐way ANOVA n = 8–14 (d) F(1, 42) = 20.74 p < 0.0001 age effect of two‐way ANOVA n = 8–14 (e) F(1, 20) = 6.47 p = 0.019 interaction effect; F(1, 20) = 9.18 p = 0.0066 age effect; F(1, 20) = 6.51 p = 0.019 treatment effect of two‐way ANOVA, adjusted p = 0.0165* p = 0.0053** n = 4–8 (f) Pearson r = 0.697 R ² = 0.486 two‐tailed p = 0.0002 n(x, y) = 24 (g) F(1, 20) = 8.19 p = 0.0096 interaction effect; F(1, 20) = 20.07 p = 0.0002 age effect; F(1, 20) = 24.70 p < 0.0001 treatment effect of two‐way ANOVA followed by Tukey's multiple comparisons test, adjusted p = 0.0003*** n = 4–8 (h) Pearson r = 0.539 R ² = 0.291 two‐tailed p = 0.0066** n(x, y) = 24