Fig. 6.
Concentration–response effects of ex vivo stimulation with lipopolysaccharide on the production of tumor necrosis factor (TNF)-α in cultured microglia. Hippocampal microglia were isolated from young (A and B) and aged (C and D) rats after either sedentary or preoperative environmental enrichment (PEE) and after surgery. Cultured microglia were stimulated with 0.1, 1, 10, or 100 ng/ml or media alone and levels of TNF-α were determined from supernatants collected 24 h later. Each vertical bar represents the mean ± SD (n = 5 in each group). To visually show the changes after intervention or surgery from baseline, the baseline response presented in figure 5A was added to the figure of each corresponding group as a dashed line. *P < 0.05 versus sedentary group, two-way ANOVA.