The effect of Galega officinalis L. extract on the content of the advanced glycation end products and their receptors in rat leukocytes under experimental diabetes mellitus

Background. Diabetes mellitus intensifies non-enzymatic glycosylation (glycation) of biomolecules under conditions of chronic hyperglycemia and facilitates accumulation of advanced glycation end products. Disorders of the cells of various tissues are caused by binding of advanced glycation end products to the corresponding receptors, the level of receptors for advanced glycation end products increases under conditions of hyperglycemia. The interaction between receptors for advanced glycation end products and advanced glycation end products leads to the formation of excessive reactive oxygen species, changes in intracellular signaling, gene expression, increased secretion of pro-inflammatory cytokines and contributes to the development of diabetic complications. The search for factors of natural origin that will slow down the development of specific complications of diabetes, determines the feasibility of studies of the corrective ability of biologically active substances isolated from medicinal plants for the process of glycation of proteins in diabetes. Materials and methods. Experimental diabetes mellitus was induced by intraperitoneal administration of streptozotocin. Separation of blood leukocytes was performed in Ficoll density gradient. To determine the extent of advanced glycation end products and receptor for advanced glycation end products in leukocyte immunoperoxidase labeling was performed. Results. A decrease in the content of advanced glycation end products in leukocy­tes under conditions of experimental diabetes mellitus was found. The obtained data indicate a possible contravention of glucose uptake by leukocytes in the studied pathology. At the same time, an increase in exposure to the receptor for advanced glycation end products leukocyte membranes in response to chronic hyperglycemia has been demonstrated. The ability of alkaloid free fraction of Galega officinalis extract to reduce the content of receptors for end products of glycation on the membranes of immunocompetent cells in diabetic animals has been confirmed, which may be due to the presence of biologically active substances with hypoglycemic action in its composition. Conclusion. Corrective effect of alkaloid free fraction of Galega officinalis L. extract on the content of receptor for advanced glycation end products in diabetes mellitus is mediated by its normalizing effect on carbohydrate metabolism.

The effect of photobiomodulation therapy of some indices of rats’ blood cells functional state under experimental diabetes mellitus

Background. Diabetes mellitus is a chronic endocrine-metabolic disease caused by an absolute or relative insulin deficiency. During diabetes, there are perfect conditions for the development of oxidative stress: the content of substrates for oxidation increases, the content of natural antioxidants decreases and the activity of antioxidant systems is suppressed. It is known that photobiomodulation therapy produce antioxidant and antihyperglycemic effects. Here we investigated its influence on blood system functioning. Materials and Methods. The study was performed on male Wistar rats. Experimental diabetes mellitus was induced by the intraperitoneal injection of streptozotocin. Leukocyte formula was calculated using blood smears stained by Romanowsky–Giemsa. Catalase activity was determined spectrophotometrically. Affinity of hemoglobin to oxygen was evaluated by spectrophotometric method in Ivanov’s modification by drawing oxygenation curves. The protoporphyrin content in whole blood was measured by analyzing its fluorescence spectra. The content of NO2-, total and inducible NO synthase activity was determined spectrophotometrically. Results. Under the action of photobiomodulation therapy on healthy animals, there was a shift of oxygenation curves to the left and a decrease of P50, whereas under irradiation of rats with diabetes, there was a shift of oxygenation curves to the right and increase in P50 compared to indices in nonirradiated animals. During diabetes, there was a decrease in protoporphyrin content compared to control, but there was a tendency to increase under photobiomodulation. Photobiomodulation therapy of rats with diabetes increased catalase activity in erythrocyte hemolysates. We revealed significant changes in leukocyte formula under photobiomodulation. The total NO synthase activity in leukocytes of rats with diabetes was higher compared to healthy animals, but decreased under the action of photobiomodulation. We found an increase in inducible NO synthase activity in leukocytes of rats with diabetes and in leukocytes of irradiated healthy animals. An increase in NO2- content in leukocytes of rats with diabetes was detected. Under photobiomodulation, NO2- content was significantly lower in rats with diabetes. Conclusion. Photobiomodulation therapy produces a corrective action on blood system during diabetes, in particular, it improves oxygen release from hemoglobin and prevents hypoxia. Simultaneously with the increase in tissue oxygen saturation, a decrease in NO synthase activity and nitrite content along with an increase in catalase activity prevents the development of oxidative stress.

Renin-angiotensin system in the regulation of renal excretory function in case of experimental diabetes mellitus

Background. The purpose of the study was to explore the role of the renin-angiotensin system in the disturbance of renal excretory function in the dynamics of alloxan-induced experimental diabetes mellitus. Materials and methods. The experiments were carried out on 78 white non-linear mature male rats with 11-, 26- and 46-day long experimental diabetes mellitus caused by intraperitoneal administration of alloxan (160 mg/kg), against the background of pharmacological blockade of intrarenal renin-angiotensin system, induced by intraperitoneal administration of сaptopril (10 mg/kg). The study of excretory function of the kidneys was provided by the clearance method under the condition of induced water 2-hour diuresis to determine the clearance of endogenous creatinine, glomerular filtration rate, relative water reabsorption, protein content in urine, its excretion. Results. Analysis of changes in renal function after pharmacological blockade of the renin-angiotensin system in rats on day 11 of alloxan diabetes showed a significant increase in diuresis, glomerular filtration rate, endogenous creatinine concentration index, and protein excretion. The pharmacological blockade of the renin-angiotensin system had practically no effect on the intensity of the relative reabsorption of water in alloxan-diabetic rats. On day 26 of alloxan diabetes after captopril administration, there was a slight decrease in final urine volume, glomerular filtration rate, relative water reabsorption, and endogenous creatinine concentration index. At the same time, captopril did not cause an antiproteinuric effect, and protein excretion even demonstrated a tendency to increase. On day 46 of alloxan-induced diabetes after administration of captopril, there was a significant reduction in diuresis, endogenous creatinine clearance and glomerular filtration rate of rats, as well as in urinary protein concentration and excretion. Conclusions. The results of the study allow us to conclude that the initial stage of renal disorders formation in alloxan-induced experimental diabetes is associated with hemodynamic-hyperperfusion nature of renal functioning with preserved renal functional reserve and the structure of the glomerular-tubular apparatus of the kidney, autoregulatory mechanisms. Mentioned compensatory-functional changes in renal function are gradually complicated by an exhaustion of renal functional reserve and pathological activation of intrarenal renin-angiotensin system with subsequent progression of hyperperfusion-ischemic kidney damage, a decrease in the number of functioning nephrons.

Pathogenetical aspects of tubulointerstitial syndrome development in alloxan-induced experimental diabetes mellitus

Annotation. The aim of our study was to explore the pathogenetical aspects of tubulointerstitial syndrome development in alloxan-induced experimental diabetes mellitus. The experiments were carried out on 20 white non-linear mature male rats, 10 with experimental diabetes mellitus (EDМ) induced by intraperitoneal administration of alloxan at a dose of 160 mg/kg of body weight, 10 intact rats served as the control group. 25 days after administration of the diabetogenic substance, the animals were withdrawn from the experiment. The concentration of sodium and potassium ions in urine and blood plasma samples was determined, followed by calculation (considering water-induced 2-hour diuresis and endogenous creatinine clearance) of glomerular filtration rate, electrolyte excretion, their filtration rate, absolute and relative reabsorption, clearance, their proximal and distal renal transport. Removed after decapitation rats’ kidneys were dissected to 3 parts – renal cortex, medulla and papilla, sodium and potassium content was determined in water-extract of the corresponding part of the renal parenchyma, and papillary-cortical, papillary-medullar and medullary-cortical concentration ion gradients were calculated. Significant suppression of papillary-medullar and papillary-cortical concentration sodium gradients, as well as a slight limitation of its medullary-cortical gradient were established. The concentration potassium gradients were significantly reduced. Statistical processing of the obtained data was carried out with the determination of the average value, standard deviations. To assess the probability of the difference between the study groups used non-parametric Mann-Whitney ranking criterion according to the algorithms implemented in the computer program “Statistica for Windows”, “Version 8.0”. There was a decrease of the sodium-potassium ratio in urine, enhanced urinary excretion of potassium and an increase of its content in urine, as well as intensification of absolute transtubular sodium transport due to equivalent augmentation of the filtration charge of this cation, increase of proximal sodium reabsorption and, to a lesser degree, – of distal one. The distal and proximal sodium reabsorption, reduced to a unit of active nephrons, was found to be decreased, and the relative reabsorption of the cation significantly exceeded the control values, contributing to the limitation of natriuresis. The results of the study suggest that in 26-day alloxan-induced experimental diabetes hemodynamic-hyperperfusion overload on the tubular apparatus of the kidney causes the development of relative insufficiency of the proximal and distal tubules, disorders of hormone-dependent reabsorption of cations, limitation of regulatory influence of aldosterone and ADH with further tubulointerstitial disturbances that unable adequate osmotic concentration of urine.

SYNAPTIC RESPONSES OF SUPERIOR CERVICAL GANGLION NEURONS OF RATS WITH EXPERIMENTAL DIABETES MELLITUS

Excitatory postsynaptic potentials (EPSP) were recorded from the superior cervical ganglion neurons (SCG) in the rats with experimental streptozotocininduced diabetes (ESD). EPSP was inducted by electrical stimulation of the cervical sympathetic trunk. It was founded that the average value of the EPSP time constant decay in the rats with ESD was 15% higher. At the same time, the amplitudes of EPSP of SCG neurons and the hexamethonium blocking effect in the rats with ESD on 30th day after streptozotocin injection didn’t differ significantly from those in control rats. This may indicate specific functional disorders associated as with steady-state elevated blood glucose level in rats as SCG neurons nicotinic cholinergic receptors.