Effects of acute stress on central and peripheral immune or inflammatory mediators

Abstract

Previous studies have shown that stress can induce inflammatory responses in the body, and contribute to deficits in learning and memory. Whether or not this is a causal relationship, however, is not well understood. This study investigated immune and inflammatory changes induced by stress; we hypothesized that cytokine secretion and white blood cell (WBC) profiles would be altered by stress exposure. Adult male rats were restrained for 30 min, and brain tissue and blood harvested 2h after the end of the stress. Flow cytometry was used to count T‐ and B‐cells from the WBC fraction of the blood. Blocks of brain tissue containing hippocampal and hypothalamic regions were dissected, homogenized in PBS, and a Milliplex MAP kit used to measure multiple cytokines in these samples and in the plasma. Acute stress did not significantly alter cytokine levels in any of our tissues. A significant reduction was seen, however, in the number of B‐cells in acutely stressed rats compared to controls (p<0.05). In conclusion, our data support our hypothesis in part, as changes in immune or inflammatory factors were seen after acute stress. Future studies will confirm and extend these data, determine the role of B‐cells during stress, and examine these responses in repeatedly stressed animals.Supported by: 8G12MD007592