RESUMO
Objective To investigate the effect of angiotensinⅡ(AngⅡ) type 1 receptor blocker losartan on the cyclooxygenase 2 (COX-2) expression in metabolic syndrome (MS)kidney. Methods Seven-week-old male obese Zucker rats,a model of MS,were randomly divided into losartan treated and untreated group,and lean Zucker rats were used as controls.The obese Zucker rata of treated group received losartan for 4 months continuously.COX-2 expression was examined for all rats after 4 months.AngⅡ-stimulated mesangial cells and cortical tissue from AngⅡ-infused C57BL/6 mouse kidney by osmotic minipumps were used in this study.RNA and protein were obtained from renal cortical tissue or mesangial cells for RT-PCR and Western blot.Results Compared to the lean controls,obese Zucker rats showed a significant increase of COX-2 expression in the renal cortical tissue and these abnormalities were prevented by administration of losartan. Furthermore,the direct stimulation of AngⅡincreased COX-2 expression in mesangial cells in vitro and renal cortical tissue in vivo.Conclusions MS-induced COX-2 expression in the kidney is regulated by AngⅡ.Losartan as a non COX-2 inhibitor can protect MS kidney,at least in part,by inhibition of COX-2 activation.