Experimental Diabetes Mellitus Research Articles

Effects of vitamin K2 administration on guided bone regeneration in diabetic rats.

The present study aimed to investigate the histomorphometric and immunohistochemical impacts of vitamin K2 on guided bone regeneration (GBR) in calvarial critical-size defects (CSDs) in diabetic rats. A total of 30 rats were used in this study, comprising 12 non-diabetic (control) rats and 18 with streptozotocin-nicotinamide-induced experimental Diabetes mellitus (DM). In all rats, two calvarial CSDs were created: one defect was left empty (E), the other was treated with bovine-derived bone graft and collagen-based resorbable membrane (GM). Study groups were as follows: control rats administered saline (n = 6, C-E and C-GM groups) or vitamin K2 (n = 6, CK-E and CK-GM groups) and diabetic rats administered saline (n = 6, DM-E and DM-GM groups) or vitamin K2 (n = 6, DMK-E and DMK-GM groups). After 4 weeks of saline or vitamin K2 administration, the rats were euthanized. Bone defect healing and new bone formation were assessed histomorphometrically, and osteocalcin and osteopontin levels were examined immunohistochemically. Percentage of new bone formation was greater in CK-GM vs. CK-E and in DMK-GM vs. DMK-E [d = 3.86 (95% CI = 16.38-28.61), d = 1.86, (95% CI = 10.74-38.58), respectively, p < .05]. Bone defect healing scores were higher in CK-GM vs. CK-E and in DMK-GM vs. DMK-E [d = 2.69 (95% CI = -2.12 to -0.87), d = 3.28 (95% CI = 0.98-1.91), respectively, p < .05]. Osteocalcin expression levels were elevated in CK-GM vs. CK-E, in DMK-GM vs. DMK-E [d = 1.19 (95% CI = 0.08-1.41), d = 1.10 (95% CI = 0.02-1.22), respectively p < .05]. Vitamin K2 enhanced osteocalcin expression levels in DMK-E vs. DM-E [d = 2.78, (95% CI = 0.56-1.53), p < .05] and in DMK-GM vs. DM-GM [d = 2.43, (95% CI = 0.65-2.10), p < .05]. Osteopontin expression was enhanced in defects treated with GM vs. E defects [C-GM vs. C-E, d = 1.56 (95% CI = 0.38-2.01); CK-GM vs. CK-E, d = 1.91 (95% CI = 0.49-1.72); DM-GM vs. DM-E, d = 2.34 (95% CI = -1.12 to -0.50); DMK-GM vs. DMK-E, d = 2.00 (95% CI = 0.58-1.91), p < .05]. The research findings suggest that administering vitamin K2 in GBR for rats with DM favorably impacts bone healing in CSDs, presenting an adjunctive strategy for bone regeneration.

Evaluation of 8-oxo-2'-deoxyguanosine as a surrogate marker of NF-κB/NLRP3 axis activation in experimental diabetes mellitus

Evaluation of 8-oxo-2'-deoxyguanosine as a surrogate marker of NF-κB/NLRP3 axis activation in experimental diabetes mellitus

Effect of Carnosine on Oxidative Damage to the Kidneys in Experinental Diabetes Mellitus

The article presents the results of a study into the effect of carnosine on oxidative damage to the kidneys in experimental diabetes mellitus. The experiment was carried out using two groups of Wistar rats: control (n=8) and experimental (n=11). In both groups, streptozotocin-induced diabetes mellitus was simulated for eight weeks. Experimental animals were intragastrically injected with carnosine (15 mg/kg) from weeks 4 to 8. The concentration of glucose, protein and creatinine excretion in urine were determined. At the end of eight weeks, the kidneys were removed from the rats to determine the indicators of oxidative stress severity (concentration of thiobarbiturate-reactive products, total antioxidant activity, activity of catalase, superoxide dismutase, glutathione peroxidase) and to conduct morphometry of the size of the renal glomeruli, the area of the vascular bed, capillaries and mesangium in the glomeruli, the number of podocytes. A comparison with the control showed the use of carnosine led to a 1.5-fold decrease in the concentration of thiobarbiturate-reactive products (p&lt;0.001), a 2.2-fold increase in the total antioxidant activity (p&lt;0.001), and a 1.2-fold increase in catalase activity (p=0.039). The area of the renal glomeruli and the mesangium in this group decreased by 1.6 times (p&lt;0.001 and p=0.04, respectively). The total area of blood flow increased by 2.4 times (p&lt;0.001), the area of one capillary, and the number of podocytes in the glomerulus increased by 1.9 times (p&lt;0.001 and p=0.001). A 3.5-fold decrease in protein concentration in urine was also noted (p=0.007). Therefore, inhibition of the formation of advanced glycation end products by carnosine in experimental diabetes mellitus attenuates oxidative damage to the kidneys. This is evidenced by a decrease in proteinuria, an increase in the number of podocytes, a decrease in the area of the renal glomeruli, and an improvement in the condition of the glomerular vascular system.

DYNAMIC PORTRAIT OF ALVEOLAR MACROPHAGES IN EXPERIMENTAL DIABETES MELLITUS

SUMMARY. Diabetes mellitus (DM) is a globally prevalent metabolic disorder with profound implications for systemic organs, yet its intricate relationship with the respiratory system, particularly the alveolar macrophages (AM), remains underexplored. The aim – to comprehensively investigate the pathological alterations in AM during the progression of experimental diabetes mellitus. Material and Methods. An experimental investigation was conducted involving 88 male Wistar rats, categorized into intact (Group 1), control (Group 2), and experimental (Group 3) groups. Experimental diabetes was induced using streptozotocin (Sigma, USA), diluted in 0.1 M citrate buffer with a pH of 4.5, at a dose of 60 mg/kg of body weight. Tissue samples were collected at intervals of 14, 28, 42, and 70 days. Electron microscopy analysis was employed to examine lung tissue fragments. Results. On the 14th day, increased functional activity of AMs was observed, marked by distinct nuclear contours and shallow nucleolemic intussusceptions. Subsequent days revealed alterations in mitochondrial morphology, Golgi apparatus, and endoplasmic reticulum, culminating in dystrophic changes by the 70th day. The study period exhibited a dynamic temporal progression, showcasing the multifaceted responses of AMs to diabetic conditions. These responses include heightened functional activity, structural modifications in organelles, and a subsequent shift towards dystrophic changes, providing a comprehensive view of the evolving dynamics of AMs during the course of experimental diabetes mellitus. Conclusions. The study reveals a dynamic temporal progression in alveolar macrophages during the course of experimental diabetes mellitus. Early heightened functional activity transitions into dystrophic changes, providing insights into the evolving functional deficiency of macrophages as diabetes advances, contributing to the understanding of diabetes-related respiratory pathology.

Age characteristics of myocardial blood supply in comorbid pathology

Understanding the age-related changes in myocardial blood supply under conditions of diabetes mellitus and stress will help reveal the pathway of diabetic cardiomyopathy, considering the age aspect. Therefore, the aim of our work is to investigate the age-related morpho-functional changes in the hemomicrocirculatory bed (HMB) of the myocardium in rats with experimental streptozotocin-induced diabetes mellitus (SDM) under conditions of chronic immobilization stress (CIS). The study used heart fragments and blood from 56 2-month-old and 6-month-old male white rats, which were divided into 3 groups: 1 group with comorbid pathology, including modeled SDM and CIS, 2 group with SDM, and 3 – control group. The material was collected 14th and 56th days from the start of the experiment. According to our findings, hyperglycemia, and stress on the 14th day of the experiment lead to spasm of the arterioles of the HMB and a significant deterioration in their permeability, as evidenced by a likely increase in the Vongenwort index in the arterioles. On the 56th days, in the experimental groups of 6-month-old rats, vacuolar dystrophy and coagulation necrosis of endotheliocytes and myocytes, focal destruction of capillary walls, thickening, and proliferation of their basement membrane, pronounced micro- and macroclasmatic changes, and capillarosclerosis are observed. In contrast, 2-month-old rats alongside destructive changes in HMB vessels show phenomena of neovascularization. Thus, SCD leads to the development of diabetic microangiopathy in the vessels of the myocardium of rats of different age groups. In animals with comorbid pathology, damage of HMB vessels are more pronounced on the 56th day of observation and is manifested by: destruction of capillary walls, capillarosclerosis. In 2-month-old rats, alongside destructively changed capillaries, we found to former new vessels with a characteristic ultrastructure. Keywords: heart, heart failure, diabetic cardiomyopathy, diabetes mellitus, cardiovascular diseases, hemomicrocirculatory bed.

The histomorphological appearance of the testes in Alloxan-induced diabetic rabbits

This study assessed the histomorphological changes in testicular tissues due to the experimental diabetes mellitus (DM) generated in rabbits with Alloxan. Twenty-four adult male rabbits were used and allocated randomly into two equal groups (n=12 of each). The first group served as a control group and received normal saline only. The second group (diabetic group) was injected with Alloxan at a 100mg/kg IP dose. The serum glucose level was estimated at (0 min), 3 days and then (1,2 and 3 months), by aspiration of a blood sample from the jugular vein mixed with anticoagulant (EDTA) to obtain serum. The testosterone hormone was assayed from the serum obtained by centrifugation of blood samples using a special kit. Testicular biopsies were harvested through surgical castration at (1,2, and 3 months) post-administration of Alloxan. Results displayed a marked increase in glucose levels in the diabetic group starting from day three till the end of the experiment, with high differences between the two groups. Moreover, testosterone levels significantly decreased in the diabetic group compared to the control group. Our histomorphological examination confirmed that Alloxan leads to testicular damage in rabbits, represented by testicular atrophy, necrosis focusing in spermatogenic cells and separation of germinal epithelium. In conclusion, the injection of Alloxan succeeded in inducing (DM) with clear alteration in studied parameters. . Key Words: Biochemical, Testicular Parameters, Alloxan, Rabbits.

Diabetes-correcting and antioxidant effects of grape pomace extract rich in natural complex of polyphenols

Background. The positive health effects of polyphenols have led to an increased scientific interest in these natural compounds over the past decade. Many studies confirm the effectiveness of polyphenols as additional therapy in diabetes, especially due to the sugar-lowering effect of polyphenols. The aim of the research was to investigate the morphological and functional state of peripheral blood erythrocytes and the indices of oxidative stress in the liver of rats with experimental diabetes and after the administration of grape pomace extract rich in natural complex of polyphenols. Materials and Methods. We obtained grape pomace extract, which contains a variety of polyphenolic compounds. Rats of the following groups were used in the experiments: control animals, animals treated with grape pomace extract rich in natural complex of polyphenols for 14 days, animals with streptozotocin-induced diabetes mellitus, and animals with streptozotocin-induced diabetes mellitus treated with grape pomace extract rich in natural complex of polyphenols for 14 days. The number of erythrocytes and reticulocytes, the concentration of hemoglobin and glycated hemoglobin were determined in the peripheral blood of rats. The activities of catalase, superoxide dismutase and the content of thiobarbituric acid-reactive substance and carbonyl groups of proteins were determined in the liver tissues of rats. Results. The study has shown an increase in the number of erythrocytes and the level of hemoglobin, a decrease in the level of glycated hemoglobin and the number of reticulocytes in the peripheral blood of rats after administration of grape pomace extract rich in natural complex of polyphenols to rats with experimental diabetes. A decrease in the content of thiobarbituric acid-reactive substance and the content of carbonyl groups of proteins of neutral and basic character and an increase in the activity of catalase and superoxide dismutase in liver tissues were found under the same conditions. Conclusions. The results indicate that the extract of the natural complex of polyphenols is capable of correcting the morphological and functional state of erythrocytes, as well as improving the activity of antioxidant enzymes and the content of marker molecules of oxidative stress in hepatocytes of rats under experimental diabetes mellitus.

Analysis of Mechanisms Underlying the Development of Endothelial Dysfunction and Functional Disorders in Experimental Diabetes Mellitus and Their Pathogenetic Correction.

On the model of alloxan-induced diabetes mellitus in rats, the development of oxidative stress and violation of the NO-producing function of the endothelium and internal organs was established. Structural changes in the vascular endothelium due to increased level of atherogenic LDL preventing access of L-arginine to endothelial NO synthase (eNOS) contribute to the development of endothelial dysfunction, which is paralleled by oxidative modification of L-arginine and the formation of inhibitors of eNOS expression (asymmetric dimethylarginine, L-NAME). These findings are indicative of reduced eNOS expression in experimental diabetes mellitus. Administration of L-arginine and its combination with L-carnitine caused an increase in the production NO metabolites and eNOS expression levels by 2.13 and 3.8 times, respectively. In parallel, improvement in the electrolyte excretory function of the kidneys, an increase in the Na,K-ATPase activity in organ homogenates, and a decrease in organ-specific enzymes in blood plasma were observed, which indicates the effectiveness of the correction of the identified violations. A way to eliminate metabolic and functional disorders with combinations of L-arginine and L-carnitine is pathogenetically substantiated. This methodological approach can be recommended for the prevention of microvascular complications in patients with type 1 diabetes mellitus.

Модель диет-индуцированного экспериментального сахарного диабета у лабораторных песчанок и дегу

According to the latest data from the International Diabetes Federation (IDF), the number of patients with diabetes has outpaced previously predicted growth rates and is expected to increase by 51% by 2045. Thus, the development and evaluation of the effectiveness and safety of hypoglycemic agents is an urgent task due to the high social significance of the problem. In preclinical studies there are many models of experimental diabetes mellitus in animals, both with the use of chemical inducers that cause damage to the islet apparatus of the pancreas, and with the use of diets. Accor­ding to the literature data, gerbils and degus are prone to hyperglycemia and insulin resistance when fed on standard laboratory diets, which are relatively high in calories compared to the food obtained by these animals in their natural habitat. Due to this feature the experimental induction of diabetes mellitus in these animal species can be modeled only through the use of a high-calorie diet. The purpose of this study was to test this hypothesis. Male and female gerbils of two age categories (14–20 and 40–41 weeks), as well as male and female degus, whose age was 65–70 weeks, were used as experimental animals. During the experiment the following indicators were evaluated: the concentration of glucose, cholesterol, triglycerides, creatinine, urea in blood plasma, the activity of dipeptidyl peptidase type 4 (DPP-4) and the parameters of the glucose tolerance test. Based on the totality of all experimental data a state close to pre-diabetic was established in male and female degus fed on a high-carbohydrate diet. This conclusion was made due to an increase in the activity of the DPP-4 enzyme and the presence of glucose tolerance by the 12th week of the experiment. The induction of experimental diabetes mellitus or latent diabetes mellitus using high-calorie diets failed in the majority of experimental animals (gerbils and degus) regardless of age. The obtained results are suggestive of the motivation for the use of these experimental models for the creation of experimental diabetes.

State of peroxidation in the brain and liver in experimental diabetes and its correction possibility with niacin-oxyethylendiphosphonatogermanate

The development of pharmacological methods to control oxidant stress manifestations in diabetes can be achieved using organic complex germanium compounds. One of the promising compounds is niacin-oxyethylenediphosphonategermanate (MIGU-4), which is an effective corrector of lipid metabolism and a stabilizer of the lipid layer of erythrocyte and hepatocyte membranes in the streptozotocin-induced diabetic model. The aim of the work is to determine the dynamics of the malondialdehyde (MDA) content, the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPO) in the brain tissue, as well as the diene conjugate (DC) content, lipid hydroperoxides (LHP), reduced glutathione (GSH) in the liver mitochondria, the serum activities of aspartate and alanine aminotransferases (AST and ALT) in experimental diabetes mellitus with the correction using a complex compound of germanium with nicotinic acid – MIGU-4 and insulin, insulin alone as well as in comparison with effectiveness of vitamin E supplementation. Materials and methods. Diabetes was induced in male Wistar rats by intraperitoneal injection of streptozotocin (60.0 mg/kg). MIGU-4 was administered intraperitoneally at a dose of ED50 that was 25.0 mg/kg. Mitochondrial membranes were obtained by differential centrifugation of the liver tissue. In rats with confirmed diabetes, parameters of peroxidation and antioxidant protection were studied by generally accepted biochemical and biophysical methods. Results. Glucose levels were 29.4 % lower in rats treated with MIGU-4 (25.0 mg/kg) after 8 weeks of streptozotocin-induced diabetes than those in untreated diabetic rats (p &lt; 0.05), while a decrease was 39.0 % (p &lt; 0.05) upon insulin treatment, and 47.2 % (p &lt; 0.05) – with combined use of the drugs. The MDA content in the brain tissue was 3.48 times higher than that in the control (p &lt; 0.05). At the same time, the activities of SOD and CAT were decreased by 46.4 % and 32.0 %, respectively, the activity of GPO was decreased by half (p &lt; 0.05). In the liver mitochondria, the DC content exceeded that in the control by 53.5 % (p &lt; 0.05), and the MDA and LHP levels were 2.48 times and 31.7 % higher (p &lt; 0.05), respectively. AST activity was almost doubled, ALT activity was 5.48 times increased. Insulin and the biologically active substance MIGU-4 used alone exerted a moderate corrective effect. The combined use of the drugs caused definite therapeutic and preventive effects as the brain content of MDA was 2.4 times decreased, the activity of SOD, CAT and GPO was increased by 45.6 %, 35.2 % and 67.3 % (p &lt; 0.05), respectively. In the liver mitochondria, the DC, MDA, and LHP contents were decreased by 41.0 %, 53.3 %, and 28.4 %, respectively, compared to those in rats with diabetes (p &lt; 0.05). The activity of SOD and CAT as well as GSH content were increased by 2.7 times, 51.9 %, and 23.0 % (p &lt; 0.05), respectively. AST and ALT activities were 42.2 % and 74.3 % (p &lt; 0.05) reduced, respectively. The combined use of MIGU-4 (25.0 mg/kg) and vitamin E (250.0 mg/kg) caused a decrease in the brain MDA content by 70.1 % (p &lt; 0.05) in experimental rats. The combination of MIGU-4 and vitamin E increased the activity of GPO by 58.3 % (p &lt; 0.05) as compared to rats with diabetes, indicating cumulative effects of these drugs. Conclusions. The use of MIGU-4 prevents the occurrence of oxidant stress manifestations in the brain tissue and liver mitochondria in streptozotocin-induced diabetes. The corrective effect size of MIGU-4 (25.0 mg/kg) corresponds to that of vitamin E (250.0 mg/kg).  

Bone remodeling in experimental diabetes mellitus and surgical menopause in Wistar rats

BACKGROUND: Osteoporosis is metabolic skeletal disease characterized with low bone mass, bone microarchitecture disturbance that together lead to high prevalence of fragility fractures. Postmenopausal osteoporosis accounts for about 80% of the osteoporosis structure in women over 50 years. Diabetes mellitus (DM) is an independent risk factor for low-traumatic fractures. The incidence of both type 2 DM and osteoporosis increases during menopause. Therefore, the study of bone metabolism in experimental diabetes and surgical menopause seems important.THE AIM of the study was to investigate bone metabolism parameters during menopause and experimental type 2 DM.MATERIALS AND METHODS: The half of female Wistar rats had been subjected to bilateral ovariectomy at the beginning of the experiment. Diabetes mellitus (DM) was modelled using a high-fat diet and streptozotocin+nicotinamide. Four weeks after the following groups were formed: «Сontrol» (females without any interventions receiving standard chew, n=5) «OE» (females after ovariectomy n=5), «DM» (females with DM, n=4), «OE+DM» (females after ovariectomy with DM, n=4). The observation period lasted 8 weeks. Bone turnover and calcium-phosphorus metabolism markers (osteocalcin, osteoprotegerin (OPG), nuclear factor-kappa-beta receptor activator ligand (RANKL), sclerostin, fibroblast growth factor-23 (FGF-23), calcium, phosphorus) were measured in the end of experiment. Bone histomorphometry was performed after euthanasia.RESULTS: Phosphorus level was significantly lower both in the «OE» group (1.63 [1.58; 1.65] mmol/L) and in the «DM» group (2.81 [2.57; 2.83] mmol /l) compared to the «Control» group (3.12 [2.55; 3.24] mmol/l) (p&lt;0.001). This marker was significantly higher in the «OE+DM» group (2.79 [2.46; 2.81] mmol/l) in comparison to the «OE» group (2.79 [2.46; 2.81] mmol /l), p=0.025. Osteocalcin level was significantly lower in the «DM» group (8.1 [7.8; 9.2] ng/ml) compared to the «Control» group (16.97 [14.07; 17.07] ng/ml ), p=0.005. A weak negative correlation (r= -0.5, p&lt;0,05) was found between glucose and osteocalcin levels (p=0.03). RANKL level was significantly lower in the «OE+DM» group (278,1 [273.1; 289.7] pg/mL) compared to the «OE» group (400.6 [394.5; 415.1] pg/mL), besides the OPG/RANKL ratio was higher in this group (0.03 [0.02; 0.035] and 0.01 [0.004; 0.014], respectively), p=0.05. In the «OE» group lower OPG level (5.1 [1.5; 5.6] pmol/L) and OPG/RANKL ratio (0.01 [0.003; 0.014]) were obtained in comparison to the «Control» group (12.3 [8.8; 14.2] pmol/l and (0.34[0.33; 0.4], p=0.025 and p=0.07, respectively. The area of bone trabeculae in the epiphyseal zone was the largest in the «Control» group (42 [39; 45]) %; the difference was significant compared to the «OE» group (29 [25; 33] %, p=0.011) and the «OE+DM» group (30 [23; 25] %, p=0.016). The area of bone trabeculae in the metaepiphyseal zone was also the largest in the «Control» group (49 [46; 52] %) compared to the «OE» (35 [25; 39] %), «DM» (31 [26; 34] %), «OE+DM» (35 [33; 38] %), p&lt;0.001. There was no difference in the thickness of the bone trabeculae among the groups.CONCLUSION: DM induction can significantly inhibit bone remodeling in animals without menopause, which is reflected in a lower osteocalcin level. Bone turnover during DM and surgical menopause is characterized by lower RANKL levels and higher OPG/RANKL ratio. The effect of ovariectomy on bone metabolism was manifested in more extensive decrease in bone trabeculae area than in DM.

Comparative study of the hypoglycemic and cardioprotective effects of glucagon-like peptide-1 receptors agonist exenatide, insulin and their combined use in myocardial ischemia/reperfusion injury in rats with experimental type 2 diabetes

Introduction. Insulin therapy used during acute myocardial infarction (AMI) is associated with a high risk of hypoglycemia and high glycemic variability. Therefore, the search for optimal therapeutic approaches which affect both cardioprotection and glycemic correction is relevant. It is known that agonists of glucagon-like peptide-1 (aGLP1) exhibit a protective effect on the myocardium and are involved in the normalization of carbohydrate metabolism. The combined use of аGLP1 exenatide and insulin can be more effective and safe but not insufficiently studied.The aim of this study was the comparative investigation of the effect of exenatide, insulin, and their combination on the volume of myocardial damage and the level of glycemia in the myocardial ischemia/reperfusion (I/RP) model in rats with experimental diabetes mellitus (DM2).Materials and methods. Neonatal streptozotocin diabetes was modeled in male Wistar rats on the 4th–5th day of life. At the age of 3 months, I/RP was fulfilled in animals with confirmed hyperglycemia. Experimental groups were formed depending on the time of therapy with insulin, exenatide, or their combination; before or after ischemia. Ischemia lasted for 40 min, while reperfusion was 120 min. The size of the myocardium necrosis zone and the changes in glycemia level and its variability were determined.Results. Insulin reduced glycemia, but it increased glycemic variability by 60 % and caused hypoglycemia in 32–37 % of animals. Exenatide reduced blood glucose concentration to the level of fasting glycemia and glycemic variability by 1.5–2 times compared with insulin. Exenatide given before ischemia reduced the area of necrosis by 2.2 times. The combined use of insulin and exenatide was accompanied by the absence of hypoglycemia and a decrease in the necrosis zone by 3.2 times compared to the control.Conclusion. The combined use of aGLP1exenatide and insulin in experimental conditions of I/RP+DM2 is the most effective and safe. This makes promising their joint use in patients with DM2, both at high risk of AMI and those undergoing AMI.

Determination of molecular mechanisms of development and course of experimental diabetes mellitus in Wistar rats

The development and progression of diabetes involves several molecular mechanisms, in particular: insulin resistance, dysfunction of beta cells, inflammatory processes. These mechanisms can disrupt insulin signaling pathways, contribute to beta-cell apoptosis, and are not necessarily dependent on the intervention of cytokines and chemokines. Additionally, genetics play a role, as some forms of diabetes are caused by genetic mutations affecting insulin production or sensitivity. The molecular mechanisms underlying the development and progression of diabetes are complex and encompass various aspects of the body’s physiology and biochemistry. Understanding these mechanisms is crucial for the development of effective methods for treating and preventing diabetes. The aim of the work is analysis of the expression of genes, related to diabetes in pancreatic tissue samples of Wistar rats. Materials and methods. The polymerase chain reaction method with real-time reverse transcription was used to analyze gene expression using the RTI Profiler™ PCR Array Rat Diabetes kit (QIAGEN, Germany), where the pancreas was the object of research in experimental animals. Results. RTI Profiler™ PCR Array Rat Diabetes profiles the expression of 84 genes, associated with the onset, development, and progression of diabetes. The panel contains genes that contribute to obesity, insulin resistance, early-onset diabetes, and its late complications. These genes are represented by functional categories: receptors, transporters, and channels; nuclear receptors; metabolic enzymes; secretion factors; signal transduction proteins; transcription factors. According to the PCR results of the study of the control group of animals and animals with experimental diabetes, we established the activity of the Nkx2-1 genes; Pik3r1; Slc14a2 with high expression compared to control animals. Conclusions. The Nkx2-1 gene has been implicated in the pathogenesis of diabetes, as evidenced by its high expression activity compared to the control group of animals. Additionally, the Pik3r1 protein shows elevated expression levels in the group of animals with experimental diabetes. These changes are believed to be part of a compensatory mechanism aimed at preserving the cellular function of the pancreatic endocrine system. Furthermore, the observed increase in Slc14a2 protein expression likely indicates the onset of late complications associated with kidney pathology in the course of diabetes.

Modern glucose-lowering treatment effect on bone remodeling in experimental diabetes mellitus and surgical menopause

BACKGROUND: Diabetes mellitus (DM) is an independent risk factor for low-traumatic fractures. On the other hand, hypoglycemic drugs can have both positive and negative effects on bone remodeling.THE AIM: Тo investigate bone metabolism parameters during surgical menopause and experimental DM under the treatment with glucagon-like peptide receptor agonist type 1 (arGLP-1) liraglutide (LIRA) and sodium-glucose cotransporter type 2 inhibitor (iSGLT-2) canagliflozin (CANA).MATERIALS AND METHODS: Female Wistar rats have been subjected to bilateral ovariectomy at the beginning of the experiment. Diabetes mellitus (DM) was modelled using a high-fat diet and streptozotocin+nicotinamide. Four weeks after the following groups were formed: “OE+DM” (females after ovariectomy with DM and without any therapy, n=4) «OE+DM+CANA» (females after ovariectomy with DM under treatment with CANA, n=4), «OE+DM+LIRA» (females after ovariectomy with DM under treatment LIRA, n=5). The treatment or observation period were continuing for 8 weeks. Calcium, phosphorus and bone turnover markers (fibroblast growth factor-23 (FGF-23), osteocalcin, sclerostin, osteoprotegerin (OPG), nuclear factor-kappa-B receptor activator ligand (RANKL), were measured in the end of experiment. Bone histomorphometry was performed after euthanasia.RESULTS: Treatment with both CANA and LIRA did not significantly affect the phosphorus-calcium metabolism, sclerostin and osteocalcin concentrations. At the same time, the level of OPG was the highest in «OE+DM ‘’ group (9.1 [7.81; 10.045] pmol/l). The differences were significant compared with «OE+DM+CANA’’ (2, 33 [1.84; 5.84] pmol/l, p = 0.003) and «OE+DM+LIRA» (1.7 [1; 2] pmol/l, p = 0.003) groups. There were no differences in OPG levels between animals treated with different drugs. Similarly, the OPG/RANKL ratio was similarly reduced with both types of treatment. In “OE+DM+CANA’’ group the bone trabeculae number of   the femur epiphysis (p=0.042) were decreased in comparison to «OE+DM» group. LIRA did not change the histoarchitectonic parameters.CONCLUSION: Bone metabolism markers did not differ when using as canagliflozin as liraglutide. Besides, canagliflosin can lead to the activation of bone resorption, which is expressed in the femur epiphyseal trabeculae number decreasing.

Study on histomorphological features of the brain tissues in animals with experimental diabetes mellitus

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Peculiarities of ionoregulatory renal function of rats in the dynamics of experimental diabetes mellitus development

Background. The purpose of the research was to study the peculiarities of ionoregulatory renal function in the dynamics of alloxan-induced experimental diabetes mellitus. Materials and methods. The experiments were carried out on 63 white non-linear mature male rats, 53 with experimental diabetes mellitus of varying duration induced by intraperitoneal administration of alloxan in a dose of 160 mg/kg of body weight, and 10 intact rats (control group). Ten, 20, 25, 30, 40 and 45 days after administration of the diabetogenic substance, the animals were withdrawn from the experiment. Ionoregulatory function of the kidneys was studied by means of the clearance method under condition of water induced 2-hour diuresis to determine the clearance of endogenous creatinine, glomerular filtration rate, sodium and potassium content in the urine and blood plasma. It was followed by calculation of the electrolyte excretion, intensity of their filtration, absolute and relative reabsorption, their proximal and distal tubular transport (including standardized by glomerular filtrate volume). Results. The ionoregulatory function of the kidneys in rats with alloxan-induced experimental diabetes is characterized by the intensification of natriuresis and kaliuresis at all stages of the experiment. An increase in the urinary sodium loss in the early stages of alloxan-induced experimental diabetes is primarily stipulated by glomerular hyperfiltration, followed by an enhancement of filtration sodium load to the nephron. The loss of proportionality between the filtered amount of sodium and its proximal reabsorption causes a decrease in the total reabsorption potential of the tubular segment of the nephron in the dynamics of alloxan-induced experimental diabetes. It is reflected primarily on the proximal tubules, and subsequently induces a functional weakening of the tubule-tubular connection and relative dysfunction of the distal segment of the nephron with subsequent inhibition of aldosterone-dependent regulatory mechanisms. Conclusions. The kaliuric reaction of the diabetic kidney may serve as one of the signs of decompensation of the renal blood flow autoregulation by tubuloglomerular feedback, which is an initiating factor for the dysfunction of the tubular apparatus of diabetic kidney.

Hyperglycemia Aggravates Periodontitis via Autophagy Impairment and ROS-Inflammasome-Mediated Macrophage Pyroptosis.

Macrophage pyroptosis drives the secretion of IL-1β, which has been recently reported to be a featured salivary biomarker for discriminating periodontitis in the presence of diabetes. This study aimed to explore whether macrophage pyroptosis plays a role in the development of diabetes mellitus-periodontitis, as well as potential therapeutic strategies. By establishing a model of experimental diabetes mellitus-periodontitis in rats, we found that IL-1β and gasdermin D were highly expressed, leading to aggravated destruction of periodontal tissue. MCC950, a potent and selective molecule inhibitor of the NLRP3 inflammasome, effectively inhibited macrophage pyroptosis and attenuated alveolar bone losses in diabetes mellitus-periodontitis. Consistently, in vitro, high glucose could induce macrophage pyroptosis and thus promoted IL-1β production in macrophages stimulated by lipopolysaccharide. In addition, autophagy blockade by high glucose via the mTOR-ULK1 pathway led to severe oxidative stress response in macrophages stimulated by lipopolysaccharide. Activation of autophagy by rapamycin, clearance of mitochondrial ROS by mitoTEMPO, and inhibition of inflammasome by MCC950 could significantly reduce macrophage pyroptosis and IL-1β secretion. Our study demonstrates that hyperglycemia promotes IL-1β production and pyroptosis in macrophages suffered by periodontal microbial stimuli. Modulation of autophagy activity and specific targeting of the ROS-inflammasome pathway may offer promising therapeutic strategies to alleviate diabetes mellitus-periodontitis.

The effect of extracts of fruits of different cultivars of Cornus mas L. on plasma lipid profile in experimental diabetes mellitus

Background. Diabetes mellitus with impaired transport of glucose from the blood into the cells against the background of absolute or relative hypoinsulinemia is accompanied by the development of dyslipidemia. Therefore, it is important to find therapeutic agents capable of alleviating the symptoms and, as a result, the course of diabetes. Screening of antidiabetic agents indicates that one of their main potential sources is natural products of plant origin. However, although a wide range of plant extracts are known to be used to treat diabetes, the use of only some of them has been scientifically proven. The aim of the study was to investigate the influence of biologically active substances available in the extracts of fruits of different cultivars of Cornus mas L. on plasma lipid profile in experimental diabetes mellitus. Materials and methods. Wistar male rats with starting weight of 140–170 g were used for all experiments. Diabetes was induced by intraperitoneal injection of streptozotocin (55 mg/kg of body weight). The animals were divided into five groups. The first (control) and the second (diabetic control) groups orally received 1 mL of water daily for 14 days. Diabetic animals of the third to fifth groups were orally administered extracts of red and yellow fruits of Cornus mas L. and the “Loganic acid” extract, respectively, in the amount of 20 mg/kg of body weight for 14 days. The concentration of low-density lipoproteins, high-density lipoproteins, triglycerides, and cholesterol was determined in the rats’ blood plasma. Atherogenic indices were calculated based on lipid profile in blood plasma. Results. The total cholesterol content in diabetic rats’ blood plasma was reliably reduced when the extract of the red fruits of the Cornus mas L. “Podolski” cultivar was administered. “Loganic acid” extract, obtained from the yellow fruits of the “Yantarnyi” and “Flava” cultivars of Cornus mas L., decreased the concentration of total cholesterol, triglycerides, and the content of low-density lipoproteins against the background of an increase in the content of high-density lipoproteins in blood plasma. The atherogenic indexes made it possible to establish that the degree of risk of cardiovascular complications due to diabetes is significantly reduced against the background of the administration of extracts of cornelian cherry fruits. Conclusions. Extracts of the fruits of the “Podolski”, “Yantarnyi” and “Flava” cultivars of Cornus mas L. correct the lipid profile of blood plasma in streptozotocin-induced diabetes animals and, as a result, may potentially prevent the development of atherosclerotic changes and cardiovascular complications. The fruits of Cornus mas L. may be potential agents in the therapy of dyslipidemia in diabetes.

Morphofunctional features of tissues and blood in rats against the background of experimental diabetes mellitus

Introduction. Increased susceptibility to infections in patients with type 1 diabetes mellitus is associated with impaired body protective functions as a result of suppressed immunity, increased cellular adhesion of microorganisms, susceptibility to catabolic processes. Purpose - to determine the morphofunctional features of tissues and blood in rats against the background of experimental diabetes mellitus (EDM); to investigate the effect of the extract of seven medicinal plants BNO 1030 in them. Materials and methods. Experimental studies were conducted on 20 male Wistar rats in order to determine their level of nicotineamideadeninedinucleotide (NAD), reactive oxygen species in white blood cells and superoxide dismutase. All animals were separated: the Group 1 was the control group of healthy rats, the Group 2 - the control group receiving BNO 1030 extract, the Group 3 included animals with the EDM without treatment, the Group 4 - rats with the EDM, which received the BNO 1030 extract. Results. After 6 weeks of development of the EDM, the NAD blood level in diabetic rats was reduced and reached (0.270±0.017) µmol/L, which is lower than that in the control group ((0.357±0.021) µmol/L). The group of diabetic rats treated with BNO 1030 extract showed its increase to (0.341±0.012) μmol/L compared to the group of diabetic animals, which did not receive the drug. While assessing the viability of white blood cells, it has been established that the death of most of these cells occurs by apoptosis against the background of the EDM. When BNO 1030 was used in the group of diabetic rats, the level of apoptotic cells decreased and amounted to 13.7% compared to the group, which was not administered with the drug (20.8%). In addition, the level of apoptosis in control rats, which also received BNO 1030, decreased by 3% versus the control group. Conclusions. The reduction of NAD content in tissues and blood in experimental animals with the EDM was determined, and its increase by 24% following the administration of BNO 1030 was established, which proves positive effect of the drug on the course of energy processes and glycolysis - the main route of carbohydrate metabolism. When carrying out experiments with laboratory animals, all bioethical norms and recommendations were observed. No conflict of interests was declared by the authors.

Morphological changes in the kidney tissue of rats with experimental diabetes mellitus and during correction with metformin and modulators of hydrogen sulfide metabolism

Annotation. Metformin is widely used for pharmacocorrection of diabetic nephropathy in type 2 diabetes mellitus. However, the mechanisms of the protective effect of metformin on the kidneys remain unclear, in particular, the contribution of the hydrogen sulfide system to metformin’s nephroprotective effect is unknown. Therefore, the aim of our study was to assess the role of metformin and its combination with modulators of hydrogen sulfide metabolism in the correction of histological changes in the kidneys of streptozotocin-induced diabetic rats. The studies were performed on 30 white non-linear male rats, which were divided into five groups: 1 group - control; group 2 – animals with experimental diabetes, which was initiated by a single intraperitoneal injection of streptozotocin (40 mg/kg of weight) in 0.1 M citrate buffer (pH 4.5); Group 3 - animals with experimental diabetes, which were treated with metformin (500 mg/kg/day, intragastrically) from the 3rd to the 28th day; Group 4 - animals with diabetes mellitus, which, along with metformin, were administered NaHS (56 μmol/kg/day, intragastrically); Group 5 - animals with diabetes mellitus, which, along with metformin, were administered propargylglycine (442 μmol/kg/day, intragastrically). Histological examinations were performed according to generally accepted methods using an Olympus BX-41 light microscope (Olympus Europe GmbH, Japan). It was found that animals with experimental diabetes develop nephrosclerosis and glomerular hypertrophy, damage to the endothelium of kidney vessels, interstitial inflammation, and edema, and dystrophic and necrobiotic changes in the glomeruli. The administration of metformin to diabetic animals reduced the severity of nephrosclerosis, glomerular hypertrophy, destruction of vascular endotheliocytes, inflammation, and damage to the glomerular apparatus. The use of the hydrogen sulfide donor NaHS increased the nephroprotective activity of metformin, while the introduction of the hydrogen sulfide synthesis inhibitor- propargylglycine, significantly reduced the protective effect of metformin on the kidneys. The obtained results of the histological examination justify the feasibility of implementation of a hydrogen sulfide donor in order to potentiate the renoprotective effect of metformin.