Walker-Mason Burn and Infection Model
- Species - rat
- Duration of study – variable but typically 7 days
- Lead time – 30 days
- Standard results – microbiology, histology
The rat burn wound model is based upon work by Drs. Walker and Mason. The model was originally created by the United State's military to mimic large, battlefield burn injuries in the hopes of developing novel therapies. In the years since its creation, the model has been adapted by us and others to expand the indications that can be screened. For example, we often use the model to study the infection complications associated with large surface area burn injuries.
- Using water immersion and a specially-constructed harness, a third-degree burn is created on the backs of rats.
- Wounds can be infected with bacteria (typically Staph or Pseudomonas) or left without external microbial contamination
- Wound healing and bioburden are monitored over a period of 7 days with and without treatment through the use of tissue biopsies
How the Model Works:
In the Figure below we plot the course of exogenously applied Pseudomonas to the burn area. Over the course of 8 days, the levels of Pseudomonas are relatively unchanging without therapeutic intervention. By day 10, the burned skin has almost completely been replaced with normal, healthy tissue which is capable of fighting the infection without treatment.
Advantages and Disadvantages of this model:
This model is very good for screening antimicrobial actives that are applied topically, although the bacteria may be more sensitive to treatment compared to bacteria in an actual wound site (ex: BRIDGE PTS's porcine infected wound model). The model is also useful for screening a large number of therapeutic agents (compared to the pig model, which is more limited) especially when additional analyses such as PK/PD are desired.
- Walker HL, McLeod CG Jr, Leppla SH, Mason AD Jr. Evaluation of Pseudomonas aeruginosa toxin A in experimental rat burn wound sepsis. Infect Immun. 1979 Sep;25(3):828-30.
- Koizumi T, Tanaka H, Sakaki S, Shimazaki S. The therapeutic efficacy of edaravone in extensively burned rats. Arch Surg. 2006 Oct;141 (10): 992-5.