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Intestinal adaptation following massive ileocecal resection in 20-day-old weanling rats
1Department of Pediatrics, Division of Neonatology, Wake Forest University Health Sciences, Winston-Salem, NC 27157, USA. qyang@wfubmc.edu
Insights
A new ileocecal resection (ICR) model in weanling rats effectively mimics human infantile short bowel syndrome (SBS), showing adaptive intestinal changes. This model is suitable for studying infantile short bowel syndrome (SBS).
Area of Science:
- Gastroenterology
- Pediatric Surgery
- Animal Models
Background:
- Infantile short bowel syndrome (SBS) lacks adequate animal models.
- Existing models do not accurately reflect human infantile SBS, often caused by necrotizing enterocolitis.
- Human infantile SBS typically involves ileocecal valve and colon resection, unlike current models.
Purpose of the Study:
- To develop a more clinically relevant animal model for infantile short bowel syndrome (SBS).
- To establish an ileocecal resection (ICR) model in developing rats.
Main Methods:
- Weanling rats underwent ileocecal resection (ICR) or sham surgery, with a control group.
- Post-surgery, rats were fed a liquid diet for 7 days, with daily monitoring of weight, intake, and stool.
- Intestinal and mucosal tissues were analyzed for weight, DNA, RNA, protein, maltase activity, and histology.
Main Results:
- The ICR model demonstrated high survival (85%) with characteristic diarrhea, hyperphagia, and poor growth.
- Adaptive responses included increased intestinal and mucosal weights, DNA, RNA, and protein.
- Enhanced distal jejunum and colon mucosal thickness and maltase activity were observed.
Conclusions:
- The ileocecal resection (ICR) model in weanling rats is a suitable model for studying infantile short bowel syndrome (SBS).
- This model provides a better representation of human infantile SBS pathophysiology.
Objective:
Few infant animal models have been used to study infantile short bowel syndrome (SBS). Most SBS models involve removal of the proximal small bowel followed by jejunoileal anastomosis, which has unclear clinical relevance to human infantile SBS that often results from surgical treatment for necrotizing enterocolitis and involves removal of the ileum, ileocecal valve, and part of or the entire colon. Our objective was to develop a more appropriate SBS model in developing rats.
Materials And Methods:
Twenty-day-old weanling rats were divided into 2 surgery groups, ileocecal resection (ICR) and sham groups, and a control group that did not undergo surgery. All were fed a liquid diet ad libitum for 7 days after surgery or for 7 days in the controls, and body weight, food intake, and stool changes were recorded daily. The rats were then euthanized and intestinal lengths and weights were recorded. Samples of intestine from the distal jejunum and proximal colon were collected for histology. Mucosal samples from the middle, distal jejunum, and colon were collected for measurements of mucosal weights, DNA, RNA, and protein levels. Maltase activity was determined in the small intestine.
Results:
Eighty-five percent of rats survived the ICR with subsequent development of diarrhea, hyperphagia, and poor growth. Adaptive responses to ICR, as compared with sham, were evidenced by increased intestinal and mucosal weights, DNA, RNA, and protein levels, increased maltase activity and villous thickness in distal jejunum, and increased mucosal thickness in the colon.
Conclusions:
This ICR model in weanling rats is appropriate for studying human infantile SBS.
