Distance of Cecum Ligated Influences Mortality, Tumor Necrosis Factor-Alpha and Interleukin-6 Expression following Cecal Ligation and Puncture in the Rat

A mainstay of laboratory research into new therapies for sepsis has been the cecal ligation and puncture (CLP) model in rodents. Previous data indicate that the number of punctures made in the cecum and needle size utilized are primary determinants of mortality. Despite this, variability exists in mortality from this model, even when needle size is held constant. The aim of the present study was to evaluate the influence of the length of cecum ligated, independent of needle size, as a determinant of mortality.We evaluated this by ligating various cecal lengths in male Sprague-Dawley rats. A double puncture was then made with a 20-gauge needle, and mortality was analyzed. Plasma TNF-alpha and IL-6 expression was assessed at 6 h. Animals received no antibiotics, were not fasted, and fluid resuscitation was administered.We determined that mortality does not begin to occur until a distance of >5% of cecal length is ligated. Further, our findings indicate that in this model, 90-100% mortality occurs 4 days following CLP when a distance of >30% is ligated. TNF-alpha and IL-6 expression is markedly increased with increasing length of cecum ligated.Our data demonstrate that the length of cecum ligated is a major determinant of mortality in the CLP model of sepsis. These findings indicate that investigators must rigorously control the distance of the cecum ligated in order to generate consistent mortality and inflammation data when utilizing the CLP model in rats. Further, the mortality from this model can be adjusted to fit the individual needs of a particular experiment.