In Vivo Modeling of Complicated Necrotizing Enterocolitis

Introduction: There is no adequate and easily reproducible model of complicated necrotizing enterocolitis (NEC) that allows to study its etiopathogenesis and test various surgical treatment options in an experiment.

Objective: To devise a method for in vivo modeling of complicated NEC using laparoscopy.

Materials and methods: Our study was conducted at the premises of the Laboratory of Experimental Surgery and Oncology (Scientific Research Institute of Experimental Medicine, Kursk State Medical University) in compliance with international ethical standards and guidelines for humane animal treatment. Fifteen immature male rabbits underwent laparoscopy under inhalation anesthesia and then subserosal injection of damaging solutions (33% H₂O₂, 10% CaCl₂, 4% KCl, 70% C₂H₅OH, 10% CH₂O) into the intestinal wall. In 24 hours, we performed laparotomy, assessed pathological changes visually, and resected the section of the intestinal tube at the injection site. Then we performed a single­layer end­to­end intestinal anastomosis. Histological samples were made from a biopsy specimen. Morphological assessment of the changes was performed.

Results: The most pronounced macro­ and microscopic changes were found in the animals injected with hydrogen peroxide. We assessed changes in the abdominal cavity 24 hours since the start of modeling and observed a pattern of partial intestinal obstruction and serous peritonitis. The morphological pattern was characterized by acute circulatory disorder in the intestinal wall with ulcerative necrotic defects and perforations.

Conclusions: Based on morphological manifestations we devised a method for modeling complicated NEC using laparoscopy. It is easily reproducible in an in vivo experiment, close to the clinical situation, and allows to simulate typical morphological changes during severe NEC.

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