The aim of this study was to explore the use of urantide as an antagonist of the urotensin II (UII) receptor, G protein-coupled receptor 14 (GPR14), to protect against atherosclerosis (AS) in rats. The AS rat model was induced by an intraperitoneal injection of vitamin D3 (VD3) into rats fed with a high-fat diet for four weeks. Urantide was then injected into the rats. Immunohistochemical staining, serum biochemical assay, reverse transcription-polymerase chain reaction (RT-PCR) and western blotting were used to investigate the expression of UII and its receptor GPR14 in the AS rat model. Four weeks after induction, pathological changes typical of AS were observed in the AS rat model. In the plaques of the aortic tunica intima and tunica media, expression of UII and GPR14 was observed. The protein and gene expression levels of UII and GPR14 in the model group were significantly increased compared with those in the normal group (P<0.01). Urantide ameliorated the pathological changes of AS in the rat model and reduced the gene and protein expression levels of UII and GPR14 (P<0.05 or P<0.01). UII is associated with AS and the UII receptor GPR14-specific antagonist, urantide, demonstrates the ability to protect against AS. Thus, this study provides new insight and experimental theories for the clinical application of urantide to treat AS.
Keywords: G protein-coupled receptor 14; artherosclerosis; urantide; urotensin II; vascular smooth muscle cells.