Social interaction modulates autonomic, inflammatory, and depressive-like responses to cardiac arrest and cardiopulmonary resuscitation

Psychological factors, including depression and social isolation, are important determinants of cardiovascular health. The current study uses a well-validated mouse model of cardiac arrest/cardiopulmonary resuscitation (CA/CPR) to examine the effect of social environment on several pathophysiological and behavioral responses to cerebral ischemia. Male experimental mice were either housed in pairs with an ovariectomized female or socially isolated for the duration of the experiment. Cardiac arrest increased the mRNA expression of the proinflammatory cytokines TNF-alpha, IL-1 beta, and IL-6, as well as the microglia marker MAC-1; expression of each of these factors, except IL-6, was further increased among socially isolated mice. Furthermore, socially isolated animals exposed to the CA/CPR procedure displayed significantly higher levels of neuronal cell death and microglia staining within the hippocampus at 7 d following surgery. Social isolation also exacerbated CA/CPR-induced depressive-like behavior and cardiac autonomic dysregulation. In the absence of ischemic damage, social environment had no significant effect on the expression of neuronal cell death, autonomic cardiac control, or behavior. Together, these data suggest that social factors influence the pathophysiological trajectory following cardiac arrest.