Rat Peritoneal (fecal) Contamination Model
- Duration of study – 2 Days
- Lead time – 40 days
- Standard results – Microbiology, Histology
This model is similar to the CLP (Cecal Ligation and Puncture) model published by many laboratories. The model's end-point is prolonging or rescuing life in the contaminated animals which will otherwise have a 100% mortality rate in a matter of a week or less. The model is excellent for testing oral, injectable and IV antimicrobial actives and has also been used to evaluate anti-inflammatory
- Feces from healthy rats are collected prior to the start of the study, homogenized and resuspended in PBS and sterilized via autoclaving.
- Sterile feces are mixed with the microorganism of choice - - typically Staph or E. coli and injected into the peritoneal space of test rats.
- Therapy can begin before, during or after infection. However, post-infection therapies must be started within 24 hours to prevent early loss of animals in the treatment group.
- Typical study durations are: time zero (to verify baseline), Day 1, Day 2, Day 4 and Day 7. It is rarely possible to proceed past the Day 7 time point due to loss of animals in the control group.
How the Model Works:
Figures 1 and 2 show data points from a study taken at time t = 0 (actually 2 hours post-infection) and on Day 1. Although this study had been designed to go for 2 days, one of the test articles greatly accelerated the loss of animals for unknown reasons and the study was terminated early. The second test article evaluated in this study shows strong antimicrobial response at the 1 day time point.
advantages and disadvantages of this model:
As with all models where death will occur without intervention, animals must be closely monitored to allow euthanasia at the first signs of psychological stress. As such, this model often generates early terminations, particularly when test articles are not effective at controlling bacteria levels.
However, the model is extremely powerful for demonstrating the efficacy of functional therapeutic interventions and is, in our opinion, an extremely relevant model for mimicking related human illness such as spontaneous ruptures or tears in the intestinal lining or failed surgical ligation procedures.
This model also has the advantage of being relatively fast and inexpensive, with the primary driver of cost being the frequency and route of application of the test articles.