Large bowel obstruction modeling method in experiment

INTRODUCTION: A large number of methods for modeling large bowel obstruction (LBO) have been proposed by laparotomy and narrowing the large bowel lumen most often in its distal sections using various appliances (rings, ligatures, strips of fabric, buttons). The majority of described methods are technically intensive, require prolonged anesthesia, are not always feasible on small laboratory animals, and, what is most important, lack the ability to reproduce low partial intestinal obstruction for a long period.

AIM: To present a method of modeling a partial prolonged LBO permitting to study anatomical, histological and functional changes in the large bowel, as well as to test novel methods of therapy (Patent RU No. 2798407, date of state registration in the State Register of Inventions of the Russian Federation on June 22, 2023).

MATERIALS AND METHODS: The experimental group included 40 rats, in whom LBO was modeled by the claimed method; the control group included 10 rats. The animals were withdrawn from the experiment on days 30 and 120 on a planned basis. For morphological macroscopic examination, a segment of the large intestine was taken including the cecum, transverse colon, descending colon with a formed cuff and a segment extending 3 cm from it distally.

RESULTS: Partial obstruction of the colon was obtained in 72.5% of animals of the experimental group. Macroscopic signs of low obturation bowel obstruction were established by morphometry. Fifty-seven-point five percent of animals of the main group survived until the day 120 of withdrawal. Mortality among the animals was 12.5% (n = 5) in both day 30- and day 120- withdrawal groups. No changes in the vital activity of animals of the control group were recorded during the entire period of the experiment. The conducted studies showed that after day 30 of the experiment, a macroscopic picture of partial LBO developed.

CONCLUSIONS: The proposed method provides a possibility to obtain the model of partial LBO for a long-term experiment. The model is quite simple, can be used on small laboratory animals and to a high extent possesses the ability of reproducing pathological situation.