Розвиток ендогенної інтоксикації у щурів із хронічним ентероколітом на фоні стрептозотоцинового діабету

Abstract

У статті досліджено особливості синдрому ендогенної інтоксикації у щурів при розвитку хронічного ентероколіту на фоні цукрового діабету, викликаного стрептозотоцином, за показниками речовин низької і середньої молекулярної маси та вмістом нуклеїнових кислот. Встановлено, що при хронічному ентероколіті на фоні стрептозотоцинового діабету у щурів розвивається ендогенна інтоксикація, яка характеризується статистично значимим зростанням загального пулу речовин низької і середньої молекулярної маси в плазмі (у 2,4 раза), проти даних контролю. Підвищення рівня досліджуваних фракцій молекул при довжинах хвиль 242, 254 і 280 нм відбувається через надмірне їх утворення в тканинах організму, в основному, за рахунок катаболічного пулу, з порушенням процесів їх елімінації. Метаболічним результатом ендотоксикозу при хронічному ентероколіті на фоні стрептозотоцинового діабету у щурів є посилення клітинної деструкції, що підтверджується зростанням рівня нуклеїнових кислот у крові щурів на 76,2%, стосовно контролю (р<0,001).

В статье исследованы особенности синдрома эндогенной интоксикации у крыс при развитии хронического энтероколита на фоне сахарного диабета, вызванного стрептозотоцином, по показателям веществ низкой и средней молекулярной массы и содержанием нуклеиновых кислот. Установлено, что при хроническом энтероколите на фоне стрептозотоцинового диабета у крыс развивается эндогенная интоксикация, которая характеризуется статистически значимым ростом общего пула веществ низкой и средней молекулярной массы в плазме (в 2,4 раза), против данных контроля. Повышение уровня исследуемых фракций молекул при длинах волн 242, 254 и 280 нм происходит из-за чрезмерного ихобразования в тканях организма, в основном, за счет катаболического пула, с нарушением процессов их элиминации. Метаболическим результатом эндотоксикоза при хроническом энтероколите на фоне стрептозотоцинового диабета у крыс является усиление клеточной деструкции, что подтверждается ростом уровня нуклеиновых кислот в крови крыс на 76,2%, относительно контроля (р <0,001).

Objective. The purpose of our study was to determine the peculiarities of endogenous intoxication in rats with the development of chronic enterocolitis against the background of diabetes mellitus caused by streptozotocin, in terms of low and medium molecular weight and nucleic acid contents. Object and methods. Experimental studies were conducted on 106 non-liner, male white rats. Our study and manipulations complied with the international principles of the European Convention for the Protection of Vertebrate Animals Used for Experimental and Other Scientific Purposes. Laboratory animals were divided into 4 groups. Group 1 consisted of intact animals, group 2 – animals with diabetes mellitus, group 3 – animals with chronic enterocolitis, and group 4 – chronic enterocolitis against the background of diabetes mellitus. Diabetes mellitus (STD) was modeled by single intraperitoneal administration to animals 2 months old, streptozotocin (Sigma Aldrich, USA, at a dose of 60 mg/kg body weight). Animals with a glucose level of at least 10.8 mmol/L after 2 weeks of streptozotocin administration had been used. Chronic enterocolitis (ChE) was modeled by free access to 1.0% carrageenan solution in drinking water during 1 month. Animal euthanasia was carried out by cardiac puncture under deep anaesthesia, in accordance with the requirements of the Animal Care Committee. Syndrome of endogenous intoxication was evaluated using measurements of low and medium molecular weight substances in blood plasma, red blood cell suspension and urine quantified by extraction-spectrophotometric method. Using the data the following indices were determined to evaluate the intensity of endogenous intoxication: Ct– total content of low and medium molecular weight substances in plasma; Cc – the value of catabolic pool of low and medium molecular weight substances in plasma; Pc% – catabolic pool of plasma; ICP – intensity of catabolic processes in plasma; K1 – distribution rate of low and medium molecular weight substances between blood plasma proteins, and erythrocyte glycocalyx; K2 – elimination process condition, indicating the ability of kidneys to excrete endotoxemia products. The total content of nucleic acids was determined spectrophotometrically according to the method of AS Spirin. Results. The indexes of low and middle molecular weight substances in blood plasma and erythrocytes significantly increased in case of experimental STD. Thus, in the blood plasma, the fraction of substances with a maximum absorption of 242 nm in the 2nd and 3rd experimental groups significantly increased by 2.0 times and in the 4th – by 2.6 times (p<0.001). In the erythrocyte suspension, the E242 index significantly increased by 1.5 times in the STD group, 1.8 times in the both ChE-group and ChE+STD group. The substances of catabolic origin, xenobiotics, decomposition products of cells, tissues, substances of microbial origin are recorded in the range of the wavelength of 238-242 nm. The next wavelength of 254 nm corresponds to the absorption spectrum of substances that do not contain aromatic aminoacids and nucleotides. It was established significantly increasing of substances’ fraction with maximum absorption of 254 nm in 2nd experimental group (by 2.0 times), 3rd (by 2.1 times) and 4th (by 2.6 times) in the plasma (p<0.001). The acid-soluble fraction E254 significantly increased in the STD group by 1.2 times, in the ChE-group by 1.3 times, and in the case of ChE+STD by1.6 times in the erythrocyte suspension. Growth of the substances at 280 nm in plasma and erythrocyte suspension in all experimental groups due to the accumulation of biologically active substances with a molecular weight of 2000D to 5000D. Thus, in the blood plasma, the fraction of substances with a maximum absorption of 280 nm in the 2nd experimental group significantly increased by 1.4 times, 3rd – by 1.6 times and 4th – by 1.9 times (p<0.01). The E280 fraction significantly increased in the erythrocyte suspension in the STD group by 1.5 times, in the ChE-group – by 1.8 times and in the case of ChE in the background of diabetes – by 1.9 times. The analysis of the calculated factors indicates that the overall pool of low and middle molecular weight substances in blood plasma was significantly higher in all experimental groups, compared to control. The growth of endogenous intoxication with streptotzotocin diabetes and chronic enterocolitis on its background occurred mainly due to the catabolic pool of this substances in plasma. In all experimental groups, the ability of the kidneys to eliminate endotoxin products is significantly reduced. The metabolic result of endotoxicosis is the enhancement of cellular degradation and other pathological processes. To confirm the assumption of cell death, the next step in our study was to determine the level of nucleic acids in the blood of rats. Thus, the content of nucleic acids in all experimental groups was significantly higher than the control group. Conclusions. Endogenous intoxication develops in chronic enterocolitis against the background of diabetes mellitus caused by streptozotocin in rats, and characterizes by the significant increasing of the total pool of low and average molecular weight substances in plasma compared to control. The increasing of the level of molecules fractions at wavelengths of 242, 254 and 280 nm due to their excessive formation in the body’s tissues, mainly their catabolic pool, with violation of the elimination processes. The metabolic result of endotoxicosis in chronic enterocolitis against streptozotocin diabetes in rats is cellular degradation increasing, which is confirmed by high level of nucleic acids in the blood.