EXPERIMENTAL INVESTIGATION OF VENOUS BLOOD PLASMA OPTICAL DENSITY IN ACUTE SMALL INTESTINE OBSTRUCTION

Objective – to investigate variations in the optical density of venous blood plasma during acute mechanical small intestinal obstruction in experimental settings.Materials and methods. A study was conducted on 50 albino non-pedigree rats, divided into a control group of 10 rats and a research group of 40. Acute mechanical small intestinal obstruction was induced in the research group by ligating a loop of the small intestine. Blood samples were collected from the jugular vein in a control group and at 6, 12, 24, and 48 hours post-induction in a research group, and their optical density was measured across a wavelength range of 200-800 nm. These results were compared with histological analyses of small intestine sections.Results. In the control group, no changes were observed in the histological structure of the small intestine tissues. After simulating obstruction, typical disorders in the tissue structure of various intestines (aff erent, eff erent, ligated) were detected, which worsened over time. Necrosis of the ligated loop of the small intestine occurred within 12 hours. Six hours post-obstruction modeling, an increase in plasma optical density (POD) was noted in the wavelength range of 200-600 nm and at 735 nm and 780 nm. After 12 hours, POD exhibited multidirectional changes in the 200-600 nm range and increased at several wavelengths in the 600-800 nm range. At 24 and 72 hours, multidirectional changes in POD persisted in the 200-600 nm range, with a general increase, while decreases were observed at 695, 710, 770, and 790 nm. Conclusions. 1. At the early stages of experimental acute mechanical small intestinalobstruction, there is a change in the optical density of venous blood plasma within thewavelength range of 200-600 nm, along with an increase in parameters at 735 nm and780 nm. 2. As intestinal loop necrosis develops, there is a signifi cant rise in optical densitybetween 600-800 nm, prolonged obstruction and infl ammatory changes in the peritonealcavity lead to fl uctuations in indicators within the 200-600 nm range and a statisticallysignifi cant increase at several wavelengths between 600-790 nm.