[Functional state of the mesenteric arteries with higt fat intake in rats with streptozotocin-induced diabetes].

An increase in the incidence of diabetes mellitus (DM) is associated with excessive consumption of fats and carbohydrates, while DM leads to the development of cardiovascular diseases. of the research was to evaluate the effect of a high-fat diet (HFD) on the functional state of the mesenteric arteries in vivo in Wistar rats with DM. . The study was conducted on 45 male Wistar rats with an initial body weight of 220-240 g, which were divided into 3 equal groups. Animals of the control group received a standard diet for 3 months. Rats of the second group (STZ) were fed a standard diet, after 8 weeks the animals were intraperitoneally injected with streptozotocin (STZ, 35 mg/kg body weight). Animals in the STZ+HFD group received HFD (50% beef tallow), and an injection of STZ (35 mg/kg). We assessed the effect of HFD on endothelium-dependent and endothelium-free reactions of phenylephrine (PE) precontracted mesenteric arteries under the action of agonists in the absence and use of blockers of NO-synthase (L-NAME), cyclooxygenase (indomethacin), and K+-channels (tetraethylammonium), using microphoto- and videorecording of vessel diameter in vivo. . DM in rats led to an increase in the constrictor reaction to FE; in animals of the STZ+HFD group, the diameter of the vessel decreased by 63.7±4.7%; in the STZ group, by 60.4±3.8%; and in the control group, by 48.9±4.1%. HFD and DM induction had no effect on the amount of relaxation under the action of sodium nitroprusside. The amplitude of acetylcholine-induced relaxation of the mesenteric arteries of rats with DM in the absence of blockers was significantly lower (by 27.1% on average in the STZ+HFD group, by 14.6% in the STZ group) compared with control animals. After NO synthase inhibition, the relaxation amplitude decreased in the STZ+HFD group by 48.6±3.2%, in the STZ group by 56.1±2.8%, and in control animals by 58.3±3.1% compared with the dilatation amplitude without the use of a blocker. Acetylcholine-induced vascular dilatation under conditions of simultaneous use of a complex of three blockers - L-NAME, indomethacin and tetraethylammonium was reduced in rats with DM treated with HFD by an average of 18.9% and in animals of the STZ group by 22.1% compared with control animals. . Thus, excessive fat intake in rats with STZ-induced DM enhances the impairment of the functional state of the mesenteric arteries compared to animals with DM that received a standard diet. In HFD in rats with DM, a decrease in endotheliumdependent vasodilation was mediated as a failure of NO-dependent relaxation mechanisms and a decrease in the efficiency of the mechanism of endothelial hyperpolarization, whereas in rats with DM fed a standard diet, it was predominantly a disturbance in the mechanism of endothelial hyperpolarization.