Inflammation is a stronger predictor of psychological trauma exposure than behavior in repeated social defeat

Abstract

Word Count: 227 Total Word Count: 3,089Abstract Post-traumatic stress disorder (PTSD) is a psychiatric illness that results in an increased risk for a variety of inflammatory diseases. The exact etiology of this increased risk in unknown, and thus, several animal models have been developed to investigate the neuroimmune interactions of PTSD.Repeated social defeat stress (RSDS) is an established preclinical model of psychological trauma that recapitulates certain behavioral and inflammatory aspects of human PTSD. Furthermore, RSDS has been utilized to subgroup animals into susceptible and resilient populations based on one specific behavioral phenotype (i.e., social interaction). Herein, we conducted an extensive investigation of circulating inflammatory proteins after RSDS, and found significant elevations in various cytokines and chemokines after exposure to psychological trauma. When categorizing animals into either Highlights• Repeated social defeat stress (RSDS) reproducibly produces peripheral inflammation • Peripheral inflammation is not coupled to social interaction testing parameters • Susceptible and resilient categorization does not reflect peripheral inflammation • Anxiety-like behavioral parameters are linked to peripheral inflammation in RSDS • Peripheral inflammation is more predictive of trauma than behavior in RSDS