Features of modeling fatty liver disease in rats of different ages based on a high-calorie diet

BACKGROUND: The problem of diagnosis, treatment and prevention of fat liver disease (FLD) is one of the actual problems of modern medicine. In this regard, the need for the creation of reliable experimental models of the FLD, which would be as close as possible to the pathogenetic patterns of the development of this disease in humans.AIM: To create an experimental model of FLD and compare the efficiency of its reproduction in rats of different ages.MATERIALS AND METHODS: The study was conducted on male Wistar rats, whose ages at the beginning of the experiment were 3 and 18 months. Control animals were fed a standard diet. The experimental rats were kept on a diet with excess fat (45 %) and carbohydrates (31 %) for 12 weeks. The liver tissue samples were taken for morphological studies of FLD. Histological preparations were made according to the standard technique. Morphometry on digital images of micropreparations was conducted using the computer program «IMAGE J». The concentration of lipids, cholesterol, and triglecerides in the liver tissue was determined, and the concentration of ALT in the blood serum was determined. To assess the biophysical properties of the liver tissue, the method of multifrequency bioimpedance measurement was used.RESULTS: The transfer of animals to a high-calorie diet developed by us led to the development of FLD. This was evidenced by an increase of the liver mass, its pale shade and soft consistency. Morphometric signs of FLD were also revealed. Hypertrophy of hepatocytes was observed with a simultaneous decrease in the nuclear-cytoplasmic ratio; accumulation of numerous lipid inclusions in the cytoplasm and the appearance of large lipid droplets replacing the voids of dead hepatocytes. The number of binuclear hepatocytes and nucleolus in the nucleus, the relative area of the sinusoid network were decreased. An increase in the concentration of lipids, cholesterol and triglecerides in the liver tissue of experimental rats, as well as the activity of ALT in the blood serum, was observed. Changes in the bioimpedance measurements of the liver tissue also indicated the  development of severe fatty degeneration of the liver in both young (to a greater extent) and old rats.CONCLUSION: The model of FLD we have advanced based on a combined (fat-carbohydrate) high-calorie diet. It leads to the development of pronounced morphological, biochemical and biophysical signs of this pathology in all experimental rats. The most pronounced manifestations of FLD are observed in young animals

Влияние прерывистой гипо- и гипероксии на состояние респираторного отдела легких

Summary. An influence of normobaric hypoxic (10 % of oxygen in nitrogen) and hyperoxic (40 % of oxygen in nitrogen) breathing sessions on the respiratory part of the lungs was investigated in rats of 3 month of age. After 28 daily hypoxic sessions, 30 min each, we detected lung hyperinflation, an enlargement of the total alveolar area and reduction in connecting tissue elements in the lungs. After 28 daily hyperoxic sessions, 60 min each, we found reduction in mean diameter, depth, cross-sectional area and the entrance size of alveoli, increased the amount of collagen fibers, the alveolar wall thickness and increased oxyproline concentration in the lungs. These findings could indicate the connecting tissue growth in the respiratory part of the lungs and worsening of oxygen diffusion through the blood-air barrier.Резюме. Исследовалось влияние сеансов дыхания нормобарической гипо- (10 % кислорода в азоте) и гипероксической (40 % кислорода в азоте) газовой смесью на состояние респираторного отдела легких 3-месячных крыс. После 28 ежедневных (по 30 мин) сеансов гипоксии обнаружилось увеличение воздушности респираторного отдела и общей площади альвеолярной поверхности, снижение количества элементов соединительной ткани в легких, уменьшение среднего диаметра, глубины, площади поперечного сечения альвеол, ширины входа в альвеолу, увеличение количества коллагеновых волокон, толщины межальвеолярной перегородки и концентрации общего оксипролина в легких. Это может свидетельствовать о разрастании соединительной ткани в респираторном отделе легких, ухудшении условий диффузии кислорода через аэрогематический барьер

Комбінований вплив переривчастої нормобаричної гіпоксії та мелатоніну на морфологічні зміни підшлункової залози спонтанно-гіпертензивних щурів

The aim of the study was to investigate the morphological changes in the pancreas of spontaneously hypertensive animals after the combined effect of intermittent normobaric hypoxia (INH) and melatonin.Materials and methods. The study was carried out in spring on 24 spontaneously hypertensive male rats (SHR line). The experimental animals were daily given a hypoxic gas mixture (12 % oxygen in nitrogen) in an intermittent mode: 15 min deoxygenation/15 min reoxygenation for 2 hours. The same rats were daily administered orally with exogenous melatonin at 10.00 at a dose of 5 mg/kg. The duration of the experiment was 28 days. Histological preparations were prepared according to a standard procedure. Morphometry of the digital images of preparations was performed using the computer program ImageJ.Results. Based on changes in morphometric parameters (reduction in the size of acini, exocrinocytes, height of the epithelium), it can be assumed that the combined effect of INH and melatonin reduces the activity of the exocrine function of the pancreas. In the endocrine part of the pancreas of experimental animals morphological signs of its activation were noted: the linear dimensions of the Langerhans islets, the number and the density of their endocrine cells increased. Experimental animals also showed a decrease in the width of interlobular and interacinar interlayers of connective tissue, which can be considered as a manifestation of the mechanism of structural adaptation that facilitates the transport of oxygen and nutrients to the parenchymal elements of the pancreas.Conclusions. The combined effect of intermittent normobaric hypoxia and melatonin leads to the appearance of morphological signs of a decrease in the activity of the exocrine part of the pancreas in hypertensive rats. At the same time, the activity of the endocrine gland function in these animals increased.Цель работы – исследовать морфологические изменения поджелудочной железы (ПЖ) спонтанно-гипертензивных крыс после комбинированного воздействия прерывистой нормобарической гипоксии (ПНГ) и мелатонина.Материалы и методы. Исследование проведено в весенний период на 24 спонтанно-гипертензивных крысах-самцах (линия SHR). Подопытным животным ежедневно подавали гипоксическую газовую смесь (12 % кислорода в азоте) в прерывистом режиме: 15 минут деоксигенация/15 минут реоксигенация в течение 2 часов. Этим же крысам ежедневно в 10.00 перорально вводили экзогенный мелатонин в дозе 5 мг/кг. Продолжительность эксперимента составляла 28 суток. Из ткани ПЖ изготавливали гистологические препараты по стандартной методике. На цифровых изображениях препаратов осуществляли морфометрию с помощью компьютерной программы ImageJ.Результаты. На основании изменений морфометрических показателей (уменьшение размеров ацинусов, экзокриноцитов, высоты эпителия) можно предположить, что совместное действие ПНГ и мелатонина снижает активность экзокринной функции ПЖ. В эндокринной части ПЖ подопытных животных отмечали морфологические признаки ее активации: увеличивались линейные размеров островков Лангерганса, количество и плотность размещения в них эндокриноцитов. Установленное уменьшение ширины прослоек междольковой и межацинусной соединительной ткани можно рассматривать как проявление механизма структурной адаптации, обеспечивающей облегчение транспорта кислорода и питательных веществ к паренхиматозным элементам ПЖ и выделение гормонов в кровь.Выводы. Комбинированное воздействие прерывистой нормобарической гипоксии и мелатонина приводит к появлению морфологических признаков снижения активности экзокринной части поджелудочной железы у гипертензивных крыс. Активность эндокринной функции железы у этих животных возрастает.Мета роботи – дослідити морфологічні зміни підшлункової залози (ПЗ) спонтанно-гіпертензивних тварин після комбінованого впливу переривчастої нормобаричної гіпоксії (ПНГ) і мелатоніну.Матеріали та методи. Дослідження виконали навесні на 24 спонтанно-гіпертензивних щурах-самцях (лінія SHR). Піддослідним тваринам щодня подавали гіпоксичну газову суміш (12 % кисню в азоті) в переривчастому режимі: 15 хвилин деоксигенація/15 хвилин реоксигенація протягом 2 годин. Цим самим щурам щодня перорально вводили екзогенний мелатонін о 10.00 у дозі 5 мг/кг. Тривалість експерименту – 28 діб. З тканини ПЗ виготовляли гістологічні препарати за стандартною методикою. На цифрових зображеннях препаратів здійснювали морфометрію за допомогою комп’ютерної програми ImageJ.Результати. На підставі змін морфометричних показників (зменшення розмірів ацинусів, екзокриноцитів, висоти епітелію) можна припустити, що поєднана дія ПНГ і мелатоніну знижує активність екзокринної функції ПЗ. В ендокринній частині ПЗ дослідних тварин виявили морфологічні ознаки її активації: збільшилися лінійні розміри острівців Лангерганса, кількість і щільність розміщення у них ендокриноцитів. Встановлене зменшення ширини прошарків міжчасточкової та міжацинусної сполучної тканини можна вважати проявом механізму структурної адаптації, що забезпечує полегшення транспорту кисню та поживних речовин до паренхіматозних елементів ПЗ і виділення гормонів у кров.Висновки. Комбінований вплив переривчастої нормобаричної гіпоксії та мелатоніну має морфологічні ознаки зниження активності екзокринної частини підшлункової залози в гіпертензивних щурів. Водночас активність ендокринної функції залози в цих тварин зростає

Morphofunctional characteristics of hepatocytes after exposure to intermittent normobaric hypoxia in normotensive and hypertensive rats

There are only few studies in which the effect of intermittent normobaric hypoxia on the liver status in animals and people with arterial hypertension has been investigated. That’s why it’s necessary to carry out these studies in animals with high blood pressure. The purpose of this work was to carry out comparative studies of the effect of dosed intermittent normobaric hypoxia on the morphofunctional state of hepatocytes of normotensive (line Wistar) and spontaneously hypertensive (line SHR) rats, age 4 months. The experimental rats were daily exposed to hypoxic gas mixture (12% oxygen in nitrogen) in intermittent mode: 15 minutes deoxygenation / 15 minutes reoxygenation for 2 hours. The duration of the experiment was 28 days. Histological, morphometric and biochemical research methods were used. The histological preparations were made by the standard methods. The slides were photographed using a digital camera on the microscope "Nikon" (Japan). The morphometric analysis was performed on digital images using the computer program "Image J". The activity of cytochrome oxidase and succinate dehydrogenase enzymes in a suspension of hepatocytes mitochondria was determined by the method of R. S. Krivchenkov. An increase was observed in the size of hepatocytes and their nucleus, in the number of binuclear hepatocytes and nucleolus in the liver of both experimental lines of animals after exposure to intermittent normobaric hypoxia. The distance between adjacent nuclei of hepatocytes decreased. Cytochrome oxidase activity in a suspension of mitochondria increased. These morphological changes took place in the liver parenchyma of the both experimental lines of rats. But they were more pronounced in the liver of rats of the Wistar line than in the SHR line. Our data indicated that dosed normobaric hypoxia had a one-way, stimulating effect on the morphofunctional activity of hepatocytes, but the severity of this effect in rats of different lines was not the same. The obtained data can have not only theoretical value, but also be of some practical interest when using intermittent normobaric hypoxia for medical and health purposes in patients with impaired liver function and arterial hypertension

Tryptophan Prevents the Development of Non-Alcoholic Fatty Liver Disease

Roman Yanko,1,* Mikhail Levashov,1,* Olena Georgievna Chaka,1 Valentina Nosar,1 Sergey G Khasabov,2 Iryna Khasabova2,* 1Department of Clinical Physiology of Connective Tissue, Bogomoletz Institute of Physiology National Academy of Sciences of Ukraine, Kiev, Ukraine; 2Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN, USA*These authors contributed equally to this workCorrespondence: Roman Yanko, Department of Clinical Physiology of Connective Tissue, Bogomoletz Institute of Physiology National Academy of Sciences of Ukraine, Bogomoletz Street 4, Kiev, 01024, Ukraine, Tel +380442562477, Email [email protected]: The main aim of this research is to study the protective effects of tryptophan on the histomorphological and biochemical abnormalities in the liver caused by a high-calorie diet (HCD), as well as its ability to normalize mitochondrial functions in order to prevent the development of non-alcoholic fatty liver disease (NAFLD).Methods: The study was conducted in male Wistar rats aged 3 months at the start of the experiment. Control animals (group I) were fed a standard diet. Group II experimental animals were fed a diet with an excess of fat (45%) and carbohydrates (31%) for 12 weeks. Group III experimental animals also received L-tryptophan at a dose of 80 mg/kg body weight in addition to the HCD. The presence of NAFLD, functional activity, physiological regeneration, and the state of the liver parenchyma and connective tissue were assessed using physiological, morphological, histo-morphometric, biochemical, and biophysical research methods.Results: HCD induced the development of NAFLD, which is characterized by an increase in liver weight, hypertrophy of hepatocytes and an increase in the concentration of lipids, cholesterol and triglycerides in liver tissue. Increased alanine aminotransferase activity in the liver of obese rats also confirm hepatocytes damage. Tryptophan added to the diet lowered the severity of NAFLD by reducing fat accumulation and violations of bioelectric properties, and prevented a decrease in mitochondrial ATP synthesis.Conclusion: The addition of tryptophan can have a potential positive effect on the liver, reducing the severity of structural, biochemical, mitochondrial and bioelectric damage caused by HCD.Keywords: fatty liver disease, essential amino acids, obesit

Influence of hypercapnia on resistance to stress and spontaneous locomotor activity of Drosophila melanogaster different lines

The effect of hypercapnia for resistance to fruit flies hyperthermic stress, life expectancy at alimentary and water deprivation and spontaneous locomotor activity. Canton-S and Oregon-R test Drosophila lines were divided into low and high are resistant to the action of carbon dioxide and contained in hypercapnic gas medium (5 % CO2) for seven generations. Under the influence of hypercapnia increased resistance to fruit flies hyperthermic stress. Life expectancy line Drosophila Canton-S high are resistant to the action of CO2 alimentary conditions of water deprivation increased 5 % and time of extinction of a half of individuals to 19 % compared with the control. In Drosophila line Oregon-R low and high are resistant to the action of CO2. the average life expectancy had a tendency to decrease i7-8 % compared with the control. It is shown that the spontaneous motor activity of both drosophila lines highly resistant to CO2 was higher compared to the low resistant. The number of flies with a positive phototaxis after adaptation to hypercapnia reduced in Drosophila all the experimental groups