[Postgenomic and structural changes in the myocardia of Wistar rats fed a high-salt diet].

The relationship between dietary sodium, hypertension, and cardiovascular injury is far from clear. One of the important links in this process can be microRNAs that have the ability to modulate gene expression at the post-transcriptional level. However, their role in this process has not been fully studied. In addition, further studies require the identification of structural changes in the myocardium in conditions of long-term consumption of a high-salt diet. The aim of the study was to evaluate the expression levels of nuclear transcription factor κB (NFκB), microRNA (miRNA)-21 and structural changes in the myocardium during long-term consumption of a diet containing 8% (high) sodium chloride in Wistar rats. Material and methods. 20 Wistar rats with initial body weight 280.5±42.7 g were divided into two equal groups. The high salt (HS) group received 8% NaCl in the diet, the control (NS) group received the standard diet (0.34% NaCl). After 4 months, systolic blood pressure was measured in rats using the cuff method on the tail; the myocardial mass index was assessed after dissection; histological and electron microscopic examination of the myocardium was performed, and the expression levels of miRNA-21 and NFκB in the myocardium were determined. Results and discussion. Consumption of a diet high in sodium chloride for 4 months did not significantly affect the level of systolic blood pressure in normotensive Wistar rats, but led to an increase in myocardial mass index by 25.0% (p<0.05). In the HS group, hypertrophy of cardiomyocytes and an increase in the wall thickness of arterial vessels were revealed. The area of perivascular fibrosis in rats of the HS-group was almost 1.8 fold higher than in the NS-group. In animals of HS-group, the relative levels of expression of NFκB (more than 2 times) and miRNA-21 (almost 6 times) increased compared with the control. It can be assumed that the negative impact on the cardiovascular system of high-salt diets is partially realized through NFκB-associated signaling pathways and miRNA-21 activation. Conclusion. In Wistar rats, long-term use of a high-salt diet results in myocardial remodeling that is not associated with changes in blood pressure. At the same time, the adverse effects of high salt intake on the myocardium are mediated, in particular, by postgenomic mechanisms, namely an increase in the expression levels of NFκB and microRNA-21.

[Aging and kidneys: problems in evaluating of the glomerular filtration rate in elderly.]

Aging causes significant changes in the kidneys. One of the most important manifestations of an aging kidney is a reduction in glomerular filtration rate (GFR). Unfortunately, there is no generally accepted, adequate method for evaluating GFR in the elderly. The perspectivies of the relatively new approaches (BIS1, BIS2, FAS) are not clear and doubtful. The feasibility of standardization of GFR values by body surface area among of the older persons has not been determined. Possible that the diagnosis setting «chronic kidney disease¼ in elderly solely on the base of GFR decline may be an inadequate approach and promote a kind of «nephrological ageism¼.

Effect of spironolactone on hypertrophy of left ventricular myocardium in wistar rats with experimental uremia.

Chronic renal failure was modeled in rats by partial nephrectomy. Blood pressure, heart rate, concentrations of aldosterone, urea, creatinine, electrolytes, and protein, index of hypertrophy of visceral organs, and 24-h diuresis were evaluated. In rats treated with spironolactone, the index of myocardial hypertrophy did not considerably differ from that in sham-operated animals, whereas in untreated rats the test parameters considerably differ from the control. We concluded that the blockade of aldosterone receptors with spironolactone produced a cardioprotective effect in Wistar rats with subtotal nephrectomy.

[Comparative structural analysis of the liver and kidneys in experimental chronic renal insufficiency]. / Sravnitel'nyi strukturnyi analiz pecheni i pochek pri éksperimental'noi khronicheskoi pochechnoi nedostatochnosti.

The enzymatic activity/succinate-, lactate-, NADP-H2- and NAD-H2-dehydrogenase, alkali and acidic phosphatase/in renal and hepatic tissues has been studied on subtotally nephrectomized rats. Activation of hepatic functions and metabolism has been shown to occur during the development of experimental chronic renal insufficiency.

[The functional activity of the portal vein as a reflection of the metabolic changes in experimental chronic kidney failure]. / Funktsional'naia aktivnost' vorotnoi veny kak otrazhenie metabolicheskikh izmenenii pri éksperimental'noi khronicheskoi pochechnoi nedostatochnosti.

The vein contractility was shown not to depend on the nitrogen-excreting function of kidneys in rats with subtotal nephrectomy. The role of veins' increasing functional activity in the organism's compensatory-adaptive response after a decrease in renal functioning parenchymal mass, is discussed.