Sara Hosseinian - Assistant professor of physiology, Department of Physiology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran- Associate professor of physiology, Department of Physiology, Faculty of Medicine, Mashhad University of Medical Scienc
Abolfazl Khajavi Rad - Assistant professor of physiology, Department of Physiology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran- Associate professor of physiology, Department of Physiology, Faculty of Medicine, Mashhad University of Medical Scienc

Background and Objective: Unilateral ureteral obstruction (UUO) causes severe renal tubule-interstitial fibrosis. Renin-angiotensin system plays an important role in pathophysiology of UUO. Because of many in the present study, the effects of loeartan against kidney fibrosis were investigated in rats with UUO.Materials and methods: 30 male Wistar rats were divided into 3 groups: Sham operated, UUO, and the animals with UUO treated with losartan. At the 4th day of the experiment, the animals were anaesthetized and then, the abdomen was opened with a midline abdominal incision and the left ureter was ligated with 4-0 silk at two points. The administration of losartan was initiated since the first day and was continued for two weeks after UUO. At the last day of the experiment, the left kidneys were removed. The expression of Collagen IV and transforming growth factor (TGF)‑β1 were meausured by immunohistochemistry. Renal interstitial fibrosis was assessed by Masson's trichrome staining.Results: Renal expression of TGF‑β1 and collagen IV, as well as interstitial fibrosis significantly increased in UU rats. Losartan significantly downregulated the expression of these fibrotic markers and interstitial fibrosis.Conclusion: Losartan could be regarded as a therapeutic agent for treatment of UUO‑induced kidney fibrosis.

Losartan, Unilateral ureteral obstruction, Fibrosis