Effect of p-tyrosol on hemorheological parameters and cerebral capillary network in young spontaneously hypertensive rats.

Background: Many pathological mechanisms are involved in the development of arterial hypertension; disturbance of the rheological properties of blood and microvascular rarefaction are among those mechanisms.

Objective: The effect of p-tyrosol (Tyr) on hemorheological parameters and microvascularization in the cerebral cortex of spontaneously hypertensive rats (SHRs) at the stage of blood pressure rising (5-11 weeks) was studied.

Methods: Blood viscosity (BV), plasma viscosity (PV), hematocrit, erythrocyte aggregation and deformability, the oxygen transport capacity index (OTCI), and the capillary network in the cerebral cortex after the course of treatment of Tyr (50 mg/kg daily i.g. for 6 weeks) were studied. Control normotensive Wistar-Kyoto (WKY) rats and control SHRs received an equivalent amount of 1% starch mucilage.

Results: In comparison with WKY rats, disturbances of rheological blood parameters and a decrease in OTCI were revealed in control SHRs at the 11 weeks of life. By the end of the experiment, brain microvascular rarefaction was observed in the control SHRs (the average density of the capillary bed was reduced due to a decrease in the number of capillaries with a diameter of 3-7 μm). In SHRs rats treated with Tyr, BV and PV, the indices of erythrocyte aggregation were lower, and OTCI was higher in comparison with control SHRs. The density of the capillary network and the number of capillaries of 3-7 μm in the cerebral cortex of SHRs rats receiving Tyr were significantly higher than the corresponding values in control SHRs.

Conclusion: When Tyr is administered to young SHRs during the development of hypertension, it limits the development of hyperviscosity syndrome, improves the oxygen transport capacity and eliminates microvascular rarefaction in the cerebral cortex.