Fig. 3.
The levels of proinflammatory cytokines in the hippocampus. The average levels of tumor necrosis factor (TNF)-α and interleukin (IL)-1β in young (A and B) and aged (C and D) rats in each group are shown. Each vertical bar represents the mean ± SD (n = 8 in each group). *P < 0.05 versus sedentary/surgery group, Kruskal–Wallis ANOVA followed by Wilcoxon–Mann–Whitney test with Bonferroni correction. PEE = preoperative environmental enrichment.