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Modification to the RITARD surgical model
1Department of Animal Resources, Walter Reed Army Institute of Research, Washington, DC 20307-5100.
Abstract:
The Removable Intestinal Tie-Adult Rabbit Diarrhea (RITARD) procedure is the surgical model of choice for studying pathogenesis of diarrheas of Campylobacter, Escherichia coli, and Aeromonas origin. Other than nonhuman primates, the RITARD rabbit is the only model that closely resembles human infection. Classically, the RITARD model is created by isolating the terminal ileum using umbilical tape placed in a slipknot fashion, and injecting the occluded segment with the organism of choice. The slipknot is removed at 4 h postinoculation and patency of the gut reestablished. We found removal of the umbilical tape to be extremely difficult, usually requiring a second surgery to gently untie the material and prevent destruction of the fragile intestinal tissue. This complication of the described procedure appeared to be related to the absorptive and abrasive nature of the tape material. The modification described uses the same idea, but a different material and a different knot pattern. The tubing was easily removed at the prescribed 4 h postsurgery, without an additional surgery. The tubing did not adhere to or damage the gut, yet did provide the occlusive seal required for a 4-h static gut. Histologically, no evidence of pressure could be found at the tie site.
Insights
A modified Removable Intestinal Tie-Adult Rabbit Diarrhea (RITARD) model using tubing instead of umbilical tape simplifies surgical procedures. This modification prevents intestinal damage and ensures easy removal, improving the RITARD rabbit model for infection studies.
Area of Science:
- Gastroenterology
- Surgical Pathology
- Infectious Disease Modeling
Background:
- The Removable Intestinal Tie-Adult Rabbit Diarrhea (RITARD) model is crucial for studying enteric pathogens like Campylobacter, E. coli, and Aeromonas.
- Existing RITARD models face complications due to umbilical tape removal, often necessitating secondary surgery and risking intestinal tissue damage.
- The RITARD rabbit model closely mimics human enteric infections, making it invaluable for pathogenesis research.
Purpose of the Study:
- To develop a modified RITARD procedure that overcomes the difficulties associated with umbilical tape removal.
- To enhance the safety and efficiency of the RITARD rabbit model for studying diarrheal diseases.
Main Methods:
- The study modified the classical RITARD procedure by replacing umbilical tape with a different material and knot pattern.
- A novel surgical approach utilized tubing to create an occlusive seal in the rabbit's terminal ileum.
- The modified tie was designed for easy removal after a 4-hour occlusion period without causing tissue damage.
Main Results:
- The modified RITARD procedure using tubing allowed for easy removal of the occlusive material at 4 hours post-surgery.
- The tubing did not adhere to or damage the intestinal tissue, unlike the traditional umbilical tape.
- Histological examination confirmed the absence of pressure-related damage at the tie site.
Conclusions:
- The modified RITARD procedure offers a significant improvement over the classical method by simplifying tie removal and preventing surgical complications.
- This enhanced RITARD model provides a reliable and less invasive approach for studying enteric infections in rabbits.
- The improved model facilitates more accurate research into the pathogenesis of diarrheal diseases caused by various bacterial pathogens.
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