Abstract: Objectibe To investigate the effect of urotensin antagonist, urantide on the expression of p38 mitogen activated protein kinase genes and proteins in atherosclerotic rats thoracic aorta. Methods One hundred and eighty wistar rats were randomly divided into normal group, model group, positive drug group, urantide 3d group, urantide 7d group and urantide 14d group. The model group was established by injecting a loading dose of vitamin D3 and feeding a high-fat diet. The morphological changes of thoracic aorta were detected by HE staining. The expression of p38 mitogen activated protein kinase genes and proteins situation in rat thoracic aorta was detected by immunohistochemistry, RT-qPCR and Western blot. Results Typical AS pathological changes occurred in the thoracic aorta of rats in the AS group, and urantide significantly reduced the pathological changes of the thoracic aorta. The expression of p38 MAPK and the gene and protein levels in the thoracic aorta of the AS group were significantly higher than those in the NC group (P<0.01). The positive expression of p38 MAPK and genes and proteins in the thoracic aorta of the rats in the Urantide group was significantly lower than that of the AS group (P<0.01). Conclusions Urantide can improve the function of thoracic aorta by inhibiting the expression of p38 mitogen activated protein kinase to achieve the purpose of treatment of AS.

Key words: urantide, urotensin II, atherosclerosis, p38 mitogen activated protein kinase