title: Sepsis modeling in mice: ligation length is a major severity factor in cecal ligation and puncture.
abstract: BACKGROUND
  The cecal ligation and puncture (CLP) model, a gold standard in sepsis research, is associated with an important variability in mortality. While the number of punctures and needle size is well described in CLP animal studies, the length of cecal ligation is often not. The relationship between cecal ligation and survival in mice is briefly reported in the literature; therefore, we devised an investigation in mice of the consequences of three standardized cecal ligation lengths on mortality and the severity of the ensued sepsis.
  
  
  METHODS
  Male C57BL/6J mice underwent standardized CLP. The cecum was ligated at 5, 20, or 100 % of its total length and further perforated by a single 20-G puncture. Mortality was analyzed. We assessed blood lactate, serum creatinine levels, and serum cytokines (TNF-α, IL-1β, IL-6, and IL-10) after procedure in a control group and in ligated mice.
  
  
  RESULTS
  Mortality was directly related to ligation length: median survival was 24 h for the "100 %" group and 44 h for the "20 %" group. Blood lactate increased proportionally with the ligation length. At 6 h post-procedure, pro-inflammatory cytokines significantly increased in the ligated group with significantly higher serum levels of IL-6 in the 100 % group compared to the other ligated groups. The 20 % group exhibited the characteristics of septic shock with hypotension below 65 mmHg, pro-inflammatory balance, organ dysfunction, and hyperlactatemia.
  
  
  CONCLUSIONS
  Cecal ligation length appears to be a major limiting factor in the mouse CLP model. Thus, this experimental model should be performed with high consistency in future protocol designs.
authors.affiliation: Department of Anesthesiology and Intensive Care, Rangueil Hospital, University Hospital of Toulouse, 1 Avenue du Professeur Jean Poulhès TSA 50032, 31059, Toulouse, Cedex 9, France. ruiz.stephanie@chu-toulouse.fr.|Inserm/UPS UMR 1048 - I2MC, Equipe 3, Toulouse, France. ruiz.stephanie@chu-toulouse.fr.
authors.forename: Stéphanie
authors.identifier: http://orcid.org/0000-0003-3111-5938
authors.initials: S
authors.lastname: Ruiz
authors.affiliation: Department of Anesthesiology and Intensive Care, Rangueil Hospital, University Hospital of Toulouse, 1 Avenue du Professeur Jean Poulhès TSA 50032, 31059, Toulouse, Cedex 9, France.|Inserm/UPS UMR 1048 - I2MC, Equipe 3, Toulouse, France.
authors.forename: Fanny
authors.initials: F
authors.lastname: Vardon-Bounes
authors.affiliation: Department of Anesthesiology and Intensive Care, Rangueil Hospital, University Hospital of Toulouse, 1 Avenue du Professeur Jean Poulhès TSA 50032, 31059, Toulouse, Cedex 9, France.
authors.forename: Virginie
authors.initials: V
authors.lastname: Merlet-Dupuy
authors.affiliation: Department of Anesthesiology and Intensive Care, Rangueil Hospital, University Hospital of Toulouse, 1 Avenue du Professeur Jean Poulhès TSA 50032, 31059, Toulouse, Cedex 9, France.
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Conil
authors.affiliation: Inserm/UPS UMR 1048 - I2MC, Equipe 12, Toulouse, France.
authors.forename: Marie
authors.initials: M
authors.lastname: Buléon
authors.affiliation: Department of Anesthesiology and Intensive Care, Rangueil Hospital, University Hospital of Toulouse, 1 Avenue du Professeur Jean Poulhès TSA 50032, 31059, Toulouse, Cedex 9, France.|EA 4564 - MATN - Laboratoire de Modélisation de l'Agression Tissulaire et de la Nociception Toulouse, Institut Louis Bugnard (IFR 150), Toulouse, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Fourcade
authors.affiliation: Inserm/UPS UMR 1048 - I2MC, Equipe 12, Toulouse, France.|Department of Physiology, Rangueil Hospital, University Hospital of Toulouse, 1 Avenue du Professeur Jean Poulhès TSA 50032, 31059, Toulouse Cedex 9, France.
authors.forename: Ivan
authors.initials: I
authors.lastname: Tack
authors.affiliation: Department of Anesthesiology and Intensive Care, Rangueil Hospital, University Hospital of Toulouse, 1 Avenue du Professeur Jean Poulhès TSA 50032, 31059, Toulouse, Cedex 9, France.|Inserm/UPS UMR 1048 - I2MC, Equipe 3, Toulouse, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Minville
keywords: Cecal ligation and puncture; Cytokine; Mice; Sepsis