Related Experiment Video
Updated: Aug 13, 2026
Use of Animal Model of Sepsis to Evaluate Novel Herbal Therapies
Published on: April 11, 2012
Polymyxin-dextran antiendotoxin pretreatment in an ovine model of normotensive sepsis
G S Doig1, C M Martin, W J Sibbald
1The A. C. Burton Vascular Biology Laboratory, Victoria Hospital Research Institute, and The Program in Critical Care, University of Western Ontario, London, Canada.
Objective:
To test the hypothesis that adult sheep pretreated with polymyxin-dextran and then made septic by cecal ligation and perforation would have fewer changes in microvascular integrity and cellular architecture in extrapulmonary organs.
Design:
Prospective, randomized, double-blind, placebo-controlled animal study.
Setting:
An animal research facility in a university-affiliated hospital.
Subjects:
Mature, male Suffolk sheep (32 to 67 kg).
Interventions:
Animals with chronic indwelling catheters were pretreated with polymyxin B-dextran (6 mg/kg) or placebo (dextran) and an intra-abdominal focus of infection was then produced by cecal ligation and perforation. Treatment (polymyxin B or placebo) was continued every 8 hrs for 48 hrs.
Measurements And Main Results:
Forty-eight hours after randomization, the polymyxin B-dextran group manifested significantly less pyrexia (p = .04), higher mean arterial pressures (p = .02), less variable serum albumin concentrations (p = .05), and a trend toward decreased lactate concentrations (p = .10). Qualitative morphometry and semiquantitative scoring of tissue from gastrocnemius muscle demonstrated that polymyxin B-dextran-treated sheep had significantly increased total capillary (p = .04) and capillary luminal areas (p = .038) and less mitochondrial swelling and damage (p = .03) compared with the placebo sheep.
Conclusions:
Pretreatment of sheep in a polymicrobial, peritonitis model of sepsis with polymyxin B-dextran resulted in a significant amelioration of sepsis-induced ultrastructural damage. In placebo-treated control animals, these ultrastructural lesions were associated with a greater severity of sepsis, as measured by the presence of pyrexia, increased lactate concentrations, and less stable blood pressures. These findings justify the investigation of the effects of polymyxin B-dextran in a post onset model of sepsis.
