Endothelium-Independent Anti-Contractile Effect of Rat Aorta Perivascular Adipose Tissue at Control and Metabolic Disorders Induced by the Cafe Diet

Abstract

The use of high-calorie nutrition can lead to morpho-functional changes of the vascular bed that have clinical importance, however, the modulatory effect of perivascular adipose tissue (PVAT) on the vascular system in this process remains poorly characterized. The aim of this work was to study the direct effect of PVAT on the contractile activity of rat aortic smooth muscle in metabolic disorders that occur when using the cafe diet (CD). It was shown that 7 weeks of keeping animals on this diet led to excessive accumulation of visceral adipose tissue, disorders of carbohydrate and lipid metabolism, manifested in the form of hyperglycemia and hypertriglyceridemia, which characterizes the development of the metabolic syndrome. An important functional role of PVAT in the regulation of vascular tone was demonstrated using wire myography on annular without endothelium segments of the thoracic aorta of the rat. In the control group of animals on a standard diet, the presence of PVAT reduced vasoconstriction caused by stimulation by phenylephrine. In the experimental group, in rats with the metabolic syndrome caused by DC, there was a decrease in the protective effect of PVAT. The implementation of this effect was carried out with the participation of voltage-dependent and/or Ca2+-activated K+-channels of smooth muscles, while the involvement of ATP-sensitive K+-channels was weak and independent from metabolic changes caused by the use of CD. Part of the anticontractile effect of PVAT was mediated through nitric oxide (NO) produced by PVAT itself. Under metabolic changes caused by CD, the endothelium-independent anticontractile effect of NO is completely eliminated without changing the sensitivity of vascular smooth muscles to it.