Reactive changes in the vessels of the rat’s duodenal mucosa in response to the effect of complex food additives

Abstract

В роботі представлені дані морфометричного дослідження при комплексній дії харчових добавок на стан судин слизової оболонки. Встановлено, що дія глутамату натрію, нітриту натрію та Понсо 4R на ранніх термінах спостереження визначається зменшення середніх значень метричних показників судин гемомікроциркуляторного русла слизової оболонки, та розширення просвіту судин крупного калібру підслизової основи. В подальшому розвиток запальної реакції з виникненням набряку призвів до зменшення діаметрів просвіту резистивної та обмінної ланок з розширенням просвіту венул, викликав виникнення гіпоксії та дистрофічних змін, з наступним відновленням показників, внаслідок компенсаторно- пристосувальних реакцій на дію подразнюючого фактору, але повної нормалізації не відбулося. Зміни судин підслизового прошарку залежали від стану судин слизової оболонки протягом експерименту.

The paper is a fragment of the research project “Restructuring of the organs of the immune, respiratory and excretory systems under the effect of various exogenous factors (monosodium glutamate, sodium nitrite, ethanol, methacrylate)”, state registration No. 0121U108234. The state of the sections of the microcirculatory bed has a significant impact on the body organs, which is crucial for their normal functioning [14]. It is known that the duodenum has a common blood, lymphatic and innervation relationship with the adjacent organs. Consequently, pathological processes occurring in these organs, could cause changes in the microcirculatory bed of the duodenum, altering its functional state [4]. Current scientific publications elucidate the results of the effects of various food additives on the organs and systems; however, insufficient data have been found to date [1–3]. The most common and widespread flavor enhancer is monosodium glutamate (E-621), which enhances taste sensations by increasing the sensitivity of the taste buds of the tongue [6]. Many foreign researchers report on their concern over the potential impact on the human health, pathophysiological and toxicological effects of monosodium glutamate [10], emphasizing its harmful effect. The findings of the studies have shown that prolonged daily consumption of monosodium glutamate, even in safe doses, leads to morphological changes in the colon wall in the form of focal inflammatory changes of the mucous membrane, circulatory disorders in the wall, erosive ulcers, as well as dysplastic alterations that could be dangerous in terms of potentiation of carcinogenesis in the colon mucosa [5]. In Ukraine, the food additive E250 (sodium nitrite) is widely used as a color retainer in manufacturing meat products [9]. Experimental study of the state of the hemo- and lympho-microcirculatory bed of the mesentery of the rats’ small intestine in the dynamics of acute oral poisoning with sodium nitrite has found the phenomena of vasodilation of the resistance section with a decrease in the rhythm of their vasomotion, venular hypertension, increased venous-arterial shunting, vascular tortuosity, stasis of erythrocyte aggregation with paravasal tissue edema [8]. Food colorants are very popular in the food industry, giving the product an attractive appearance, and one of them is E124 food additive [12]; however, most of synthetic colorants are harmful for human health. That is due to the product of their cleavage, benzidine, which induces various tumors in humans and animals. Another component of the azo dye, p-phenylenediamine, is a contact allergen. [11]. The purpose of the study was to establish the dynamics of changes in the metric parameters of the blood microcirculatory bed of the mucous membrane and the vessels of the submucous layer of the rat duodenum in normal condition and under the effect of monosodium glutamate, sodium nitrite and Ponceau 4R complex food additives. Material and methods. 84 outbred mature male rats were involved into the experiment. The rats of control group consumed drinking water and received saline per os. The rats of the experimental group, with access to water ad libitum, consumed 10 % sodium nitrite solution. Monosodium glutamate was administered at a dose of 20 mg/kg in 0.5 ml of distilled water, Ponceau 4R at a dose of 5 mg/kg in 0.5 ml of distilled water once daily per os. The doses of food additives were twice lower the allowable normal rate in food products. The evaluation of the rats’ adaptive behavior was made with the use of the “open field” test. [15]. The animals were sacrificed within 1, 4, 8 and 16 weeks under thiopentone anesthesia overdose. After euthanasia, the fragments of the duodenal wall were fixed in 10% neutral formalin solution for three days. Subsequently, the pieces of the duodenal wall, fixed in formalin, were embedded into paraffin [13]. Sections of the 5–10 μm thick were obtained using the sliding microtome and were mounted on the slides by stenciling technique. After staining with hematoxylin and eosin, the sections were enclosed into polystyrene and studied in the light microscope. The light microscope equipped with DCM 900 digital microphoto attachment and software, adapted to the studies, have been used for microimaging and morphometric study. Statistical processing of morphometric data was made using the Excel software [7]. Results of the study and their discussion. Morphometric study of the diameter of the lumen of the vessels of the blood microcirculatory bed of the rat duodenal mucosa showed that in control rats, the diameter of the lumen of arterioles, capillaries and venules was 12.51±0.01 μm, 4.23±0.04 μm and 16.5±0.05 μm, respectively (table 1).