Figure 5. a–c, TNFα (a), IL-1β (b), and IL-6 (c) gene expression in isolated microglia 2 h following stimulation with increasing doses of LPS. Means ± SEM are plotted; n = 4 in each group. a, TNFα. There was a significant main effect of physical activity (locked, runners), F(1,24) = 37.03, p < 0.001, a significant main effect of LPS dose (0, 0.1, 1, 10, 100 ng), F(4,24) = 206.29, p < 0.0001, and a significant physical activity × LPS dose interaction, F(4,24) = 22.45, p < 0.0001. At all doses of LPS, even the 0 ng dose, TNF gene expression was significantly higher in microglia of locked wheel rats than that of runners (p < 0.05). b, IL-1β. There was a significant main effect of physical activity, F(1,24) = 17.23, p < 0.01, a significant main effect of LPS dose, F(4,24) = 224.78, p < 0.0001, and a significant physical activity × LPS dose interaction, F(4,24) = 4.07, p < 0.01. IL-1β gene expression was significantly higher in microglia of locked wheel rats than that of runners at the 0 ng (p < 0.002), 0.1 ng (p = 0.05), 1 ng (p < 0.01), and 10 ng (p < 0.05) doses, but not the 100 ng dose (p > 0.05). c, IL-6. There was no significant main effect of physical activity, F(1,24) = 4.35, p > 0.05, a significant main effect of LPS dose, F(4,24) = 117.19, p < 0.0001, and a significant physical activity × LPS dose interaction, F(4,24) = 7.35, p < 0.0005. IL-6 gene expression was significantly higher in microglia of locked wheel rats than that of runners only at the 100 ng dose (p < 0.005).