An Exaggerated Inflammatory Response after CLP Correlates with a Negative Outcome

Abstract

Sepsis is the leading cause of morbidity and mortality in the surgical intensive care unit. We postulate that the variable clinical profile of septic patients is the product of multiple factors, including initiating insult, environment, and genetic make-up. This hypothesis was tested by changing the severity of the insult and the genetic background in an experimental murine model of sepsis. Eight-week-old, male A/J and C57BL/6J (B6) mice underwent cecal ligation and puncture (CLP). The cecum was ligated just below the ileocecal valve (>1-cm ligation) or 1 cm from the end of the cecum (1-cm ligation) and single punctured using a 16- or 25-gauge needle (CLP16 or CLP25) or double punctured with a 25-gauge needle (CLP25 x 2). Cytokines were measured in plasma samples by ELISA at different time points after CLP. Elevated TNF-alpha and IL-6 plasma levels were observed in A/J as compared to B6 mice at 10 and 20 h after CLP16 (1-cm ligation). In contrast, IL-10 levels were decreased in A/J versus B6 mice at 6 h but increased at 10 h. After CLP25 and CLP25 x 2 (1-cm ligation), TNF-alpha was significantly increased at 10 h, but there was no difference in IL-10 and IL-6. CLP with >1-cm ligation resulted in increased cytokine expression after CLP25, CLP25 x 2, and CLP16 versus 1-cm ligation. Mortality after CLP16 was significantly higher in B6 mice with >1-cm versus 1-cm ligation. A/J mortality did not differ between the two procedures. Mortality rate and cytokine profiles after CLP vary depending on the insult severity and the genetic make-up.