Figure 3

CUS and chronic PS lead to a suppressed inflammatory response to subsequent LPS challenge. Mice were subjected to 28 days of daily CUS or chronic PS and given an LPS challenge 14 days after the final day of stress. A 2 (LPS treatment) × 3 (Stress) ANOVA revealed that the inflammatory response to LPS was blunted (compared to controls) in mice subjected to CUS and chronic PS within the midbrain (TNF, IL-1) and hippocampus (TNF, CD45, IL-1). Within the midbrain of chronic PS mice, however, LPS did elicit a significant increase in TNF mRNA compared to chronic PS mice treated with saline (p < 0.05). A trend for an increase in IL-1 mRNA was also observed in CUS and chronic PS mice within the midbrain but did not reach statistical significance; p = 0.08 and p = 0.07, respectively. Additionally, while there was a tendency for chronic stress to increase basal levels of inflammation, this did not reach significance; midbrain (TNF & IL-1, p = 0.07) and hippocampus (IL-1, p = 0.08). Furthermore, while LPS increased plasma CORT levels in all LPS treated mice, no interaction with stress was observed. Data are expressed as percent change from control and presented as Mean ± SEM. Columns that do not share the same letter are significantly different (Two-way ANOVA p < 0.05). n = 6-8/group.