Comparision between rectal biopsy techniques: experimental model in rabbits

• Grant number: 22/00553-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: April 01, 2022
• End date: March 31, 2024
• Field of knowledge: Health Sciences - Medicine - Surgery
• Principal Investigator: Pedro Luiz Toledo de Arruda Lourencao
• Grantee: Reinaldo Cesar Silveira Filho
• Host Institution: Faculdade de Medicina (FMB). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil

Abstract

The use of rectal biopsy for the diagnosis of intestinal aganglionosis in children is well established. However, until today, there is no consensus on the best technique for obtaining these samples. In a recent systematic review, no randomized clinical trials were found that performed the comparison between the results obtained through the different techniques of rectal biopsies, and that allowed analysis with robust evidence. Objective: to identify, through an experimental model in rabbits, which of the rectal biopsy techniques is capable of providing a higher rate of adequate samples for histopathological analysis of the submucosal nerve plexuses, with a lower rate of complications and with less inflammation and/or fibrosis when evaluated 15 days after the procedures. Methodology: an experimental model in 28 rabbits. The animals will be randomized by lot, divided into 4 experimental groups (surgical biopsy, suction biopsy, punch biopsy, and endoscopic biopsy) and 1 sham control group. The rectal wall samples will be collected and processed by the Hematoxylin & Eosin method to evaluate the presence and characteristics of the submucosal nerve plexuses. After the experimental and simulated procedures, the animals will be monitored for 14 days, investigating possible complications. On the 15th day after the procedures, the animals will be euthanized and submitted to end bloc resection of the rectum. These surgical specimens of the rectum will be evaluated in histopathology to investigate the presence of inflammatory reaction, granulation tissue, and collagen genesis. Expected results: we hope to identify which rectal biopsy technique is capable of providing more adequate samples, with fewer complications and with less inflammatory reaction and/or local fibrosis. (AU)