Red raspberry (Rubus idaeus) consumption restores the impaired vasoconstriction and vasorelaxation response in the aorta of the obese Zucker rat, a model of the Metabolic Syndrome

Abstract

Metabolic Syndrome (MetS) increases the risk of cardiovascular disease. Whole red raspberry (WRR) consumption on vascular function was investigated in the obese Zucker rat (OZR), model of MetS. Male OZR and their lean littermates (LZR) were placed on a control (C) or an 8% w/w WRR-enriched diet for 8 weeks. Phenylephrine (Phe)-induced vasoconstriction and acetylcholine (Ach)-induced vasorelaxation were measured in aortic rings in the presence or absence of L-N-monomethyl-arginine (L-NMMA) and mefenamic acid (MFA). Phe-induced vasoconstriction was lower in the OZR-C compared to LZR-C (p < 0.05). The WRR diet partially restored aortic response in the OZR-WRR aorta (p < 0.05) compared to OZR- C. The OZR-WRR group pre-treated with L-NMMA increased compared to OZR-C (p < 0.05). Pre-treatment with L-NMMA, maximal relaxation response was higher in the OZR compared to the LZR (p < 0.05). With L-NMMA, maximal relaxation response in OZR-WRR (p < 0.05) was lower compared to the OZR-C. Prostacyclin I2 concentration was higher in the OZR compared to the LZR (p < 0.05) and was attenuated in the OZR-WRR (p < 0.05). Aortic expression of eNOS and COX-2 were downregulated in the OZR-WRR (p < 0.05). In conclusion, WRR restores the impaired vascular tone of the OZR by enhancing Phe-induced vasoconstriction and attenuating Ach-induced vasorelaxation.