Effect of the combined administration of metoprolol and dihydroquercetin on the rheological properties of blood in spontaneously hypertensive rats (SHRs)

Abstract

Introduction. Hyperviscosity syndrome plays an important role in the pathogenesis of arterial hypertension and its complications associated with impaired microcirculation in target organs. Therefore, along with the use of antihypertensive drugs, it is important to pay attention to the correction of the hyperviscosity syndrome with means of hemorheological agents.The aim is to study the effect of metoprolol and its combined use with dihydroquercetin (DHQ) on the rheological parameters of blood in rats with spontaneous arterial hypertension.Materials and methods. The experiments were carried out on normotensive male Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHRs). SHRs of the experimental groups received metoprolol (50 mg/kg) or metoprolol and DHQ (50 mg/kg each) daily intragastrically for 6 weeks in 1 % starch mucus; SHRs of the control group and normotensive rats received 1 % starch mucus according to the same scheme. Systemic blood pressure was registered in awake animals. Blood was sampled from the catheterized right common carotid artery. Blood viscosity, plasma viscosity, hematocrit, erythrocyte aggregation and deformability were studied.Results. Compared with the parameters in normotensive rats, SHRs showed significant increase of blood viscosity, hematocrit, erythrocyte aggregation, and decrease of erythrocyte deformability. The course administration of metoprolol induced to a further increase in blood viscosity at low shear rates (15–45 s–1); plasma viscosity, hematocrit and micro-rheological parameters in rats of this group did not significantly differ from those in the control. With the combined administration of metoprolol and DHQ, blood viscosity at shear rates of 300 and 450 s–1 and erythrocyte aggregation were significantly lower than in the control SHRs.Conclusions. The course administration of metoprolol increases the severity of the hyperviscosity syndrome in SHRs. The use of DHQ together with metoprolol partially eliminates adverse effects of the beta blocker on blood rheology parameters.