['Renal interstitial fibrosis is the common pathway in progressive renal diseases, where oxidative stress promotes inflammation and macrophage infiltration. Febuxostat is a novel nonpurine xanthine oxidase (XO)-specific inhibitor for treating hyperuricemia. While some reports suggest a relationship between hyperuricemia and chronic kidney disease (CKD), the renoprotective mechanism of an XO inhibitor in CKD remains unknown. Recent reports have focused on XO as a source of oxidative stress.', 'Here, we investigate the potential of febuxostat to reduce fibrogenic and inflammatory responses in an established interstitial fibrosis model-unilateral ureteric obstruction (UUO). Male Sprague-Dawley rats were divided into three groups: sham-operated group, vehicle-treated UUO group, and febuxostat-treated UUO group.', 'Treatment with febuxostat diminished XO activity in obstructed kidneys, and suppressed nitrotyrosine, a marker of oxidative stress. Consequently, febuxostat inhibited early proinflammatory cytokine expression, followed by a reduction of interstitial macrophage infiltration. In addition, febuxostat suppressed transforming growth factor-β messenger RNA expression, thereby ameliorating smooth muscle alpha actin and type I collagen expression.'] Does use of xanthine oxidase inhibitor febuxostat inhibit renal interstitial inflammation and fibrosis in unilateral ureteral obstructive nephropathy?