Fig. 3

Age-dependent expression of TNF-α, IL-6, IL-1β in mice brain tissues, assessed by ELISA and immunohistochemistry. The protein expression levels of (a) TNF-α, (b) IL-6, (c) IL-1β in brain samples from young and middle-aged mice, measured by ELISA. Immunostaining of mice cerebral cortex tissue samples with antibodies against (d-h) TNF-α, (i-m) IL-6, and (n-r) IL-1β. (d, i, n): young control mice. (e, j, o): young P. gingivalis infected mice. (f, k, p): middle-aged control mice. (g, l, q): middle-aged P. gingivalis infected mice. Scale bar: 50 μm. “**” indicates statistically significant differences (P < 0.01) between the P. gingivalis infected mice and the mice in the corresponding control group