Apelin-induced hemorheological alterations in DOCA-salt hypertensive rats.

Apelin is a hypotensive peptide. Red blood cell (RBC) deformability and aggregation were previously demonstrated to be altered in various hypertension (HT) models. In the present study, we investigated possible alterations in RBC deformability and aggregation in response to apelin in DOCA-salt hypertensive rats. Rats were randomly divided into 4 groups: Control (C), Hypertension (HT), Apelin, and Apelin + Hypertension (Apelin + HT). HT was induced by injection of DOCA-salt (25 mg/kg, s.c.) twice weekly for 4 weeks, whereas apelin was administered (200 μg/kg i.p.) for 17 days. RBC deformability and aggregation were determined using an ektacytometer. Blood pressure was monitored using a tail cuff system. Systolic blood pressure was decreased in the Apelin and Apelin + HT groups and increased in the HT group. RBC deformability was not significantly altered in the HT group. Apelin administration induced a statistically significant increase in RBC deformability in control animals, whereas erythrocytic deformability in the Apelin + HT group was decreased compared to the Apelin group. RBC aggregation of hypertensive animals was reduced compared to controls. Apelin administration induced increased RBC aggregation in hypertensive rats. Our results showed favorable effects of apelin on RBC deformability in control animals, but not in hypertensive rats.