Chronic stress induces persistent low-grade inflammation

Abstract

Introduction: This study sought to determine if the systemic cytokine profile of rodents subjected to chronic restraint stress leads to persistent low-grade inflammation.

Methods: Male Sprague-Dawley rats were subjected to restraint stress for a total of seven or fourteen days. Urine norepinephrine (NE), plasma interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-α), C-reactive protein (CRP) were assessed with ELISA. Liver expression of IL-6 and TNF-α were assessed with real time PCR.

Results: Chronic stress at 7 and 14 days sequentially increased plasma acute phase reactants (NE, IL-6, TNF-α, and CRP), liver IL-6 expression, hematopoietic progenitor cell mobilization, and decreased erythroid progenitor colony growth. Weight gain was reduced by chronic stress compared to each models' naïve counterpart.

Conclusions: Combining this model with trauma and sepsis models will allow evaluation of the contribution of persistent inflammation in disease progression and outcomes.

Keywords: C-reactive protein; IL-6; Inflammation; Norepinephrine; Stress.