Differential local and systemic tumor necrosis factor-alpha responses to a second hit of lipopolysaccharide after hemorrhagic shock.

Background: The immune response to subsequent stressors after traumatic hemorrhage and resuscitation (HR) may be dependent on timing and counterinflammatory cytokine expression. Our hypothesis was that the timing of the second hit would influence the immune response, and we investigated whether an early second stimulus after HR would result in worse acute lung injury.

Methods: One hour after HR or sham shock (Sham), mice were given intraperitoneal (IP) injections of lipopolysaccharide (LPS) or saline (Sal).