#1749 Influence of high saline diet on myocardial remodeling, microRNA-21i and NFkB expression in myocardium
Authors: Khasun Mokhamad , Beresneva Olga , Parastaeva Marina , Ivanova Galina , Bogdanova Evdokia , Zaraiski Mikhail , Kucher Anatoly 
Published: May 2024

Abstract

Background and Aims
There is now increased interest in the study of morpho-functional myocardial changes in excess NaCl consumption, which develop independently of AD dynamics. Myocardial remodeling may involve microRNAs that modulate gene expression at the post-transcription level. However, their role in this process has not been fully explored. The purpose of the study is to assess the levels of expression of the nucleic transcription factor kV (NFkB), microRNA-21 and structural changes in the myocardium at long-term consumption of Wistar diet with high (8%) table salt content.

Method
Male Wistar rats (body mass 280.5 42.7 g) were divided into two groups of 10 animals. For 4 months, the control rats (NaCl) received a standard diet (0.34% NaCl), and the animals of the other group received a high salt diet (8% NaCl) (HS). Laboratory food varied only in NaCl content. 4 months later in rats systolic AD was measured, myocardial mass index (IMM) was evaluated, myocardial histology was performed (paraffin coloration - hematoxylin-eosin, Masson), relative expression levels of my RNA-determined 21 and NFkB in the myocardium, sodium content in the urine and blood serum. Statistical analysis used the t-Student criterion and the Mann-Whitney test. The differences were considered significant at p &lt; 0.05.

Results
Excess NaCl (8%) in the diet had no effect on animal body weight (370.5 32.0 g in HS group, 393.0 21.4 g in NS group, p &gt; 0.05) and systolic AD. In the HS-Group, the average AD was 134.5 8.9 mm old, and in the NS-Group - 134.8 5.2 mm old. (p &gt; 0.05). However, HS-group IMM rats were 25% higher than NS-group rats (p &lt; 0.05). The daily water consumption in the HS group was on average 33% higher than in the control, the daily diuresis also increased (10.5 5.7 ml against 5.7 2.9 ml in the NS-group, p &lt; 0.001) and the sodium content in the urine (81.25.72 mmol/l against 161.18.57 mmol in the NS-01). There was no difference in the sodium content of the blood serum. Hypertrophy of cardiomyocytes, protein dystrophy, and increased wall thickness of arterial vessels (NS-20,42 3,53, HS-27,61 4,93, µm were identified in the HS-group; p &lt; 0.01). The area of perivascular fibrosis in rats of the HS group (14876 ± 3803.7 µm2) was almost 1.8 times higher than that in the NS group (8426.0 ± 3012.2 µm2, p &lt; 0.03). The thickness of cardiomyocytes (NS-12.97 1.53, HS-20.28 1.90 µm, p &lt; 0.001) also increased in rats on the HS diet. In animals of the HS group, the relative expression levels of NFkB (more than 2 times) and microRNA-21 (almost 6 times) in the myocardium increased compared to the NS group. It can be assumed that the adverse effect on the cardiovascular system of high-salt diets is partially realized through NFκB-associated signaling pathways and the activation of microRNA-21.

Conclusion
Long-term use of a high-salt diet in Wistar rats results in myocardial remodeling unrelated to changes in AD levels. In this case, the high salt intake effects on the myocardium may be mediated by an increase in NFkBy and microRNA-21 expression levels.