Rutin ameliorates kidney interstitial fibrosis in rats with obstructive nephropathy

• Rutin ameliorates kidney tubulointerstitial injury and fibrosis after UUO.
• Rutin decreases macrophage infiltration in UUO kidneys.
• Rutin reduces expression of proinflammatory cytokine in UUO kidneys.
• Rutin suppresses NF-κB activation and TGF-β1/Smad3 signaling.

Rutin reportedly conveys many beneficial effects, including renoprotection; however, it has not yet been demonstrated to have a renoprotective effect against obstructive nephropathy. The present study is the first to show a protective effect of rutin against obstructive renal injury induced by unilateral ureteral obstruction (UUO). A total of 24 male Wistar rats were randomly divided into four groups of six rats each, including vehicle- or rutin-treated sham operated groups, and vehicle- or rutin-treated UUO groups. Rats received daily oral gavage of rutin (100 mg/kg) for 2 weeks. All rats were euthanized on postoperative day 14. Histological findings showed that rutin administration significantly reduced renal interstitial injury and suppressed interstitial collagen deposits in UUO rats. Moreover, rutin decreased macrophage infiltration, proinflammatory cytokine expression and phosphorylation of nuclear factor-κB p65. Furthermore, rutin inhibited extracellular matrix accumulation by reducing expression of type I/III collagen and fibronectin. Rutin also prevented the epithelial-mesenchymal transition processes of renal tubular cells by decreasing α-smooth muscle actin expression and retaining E-cadherin expression. These effects of rutin were in parallel with the reductions in Smad3 activity and pivotal to the fibrogenic potential of TGF-β1. Taken together, the renoprotective effects of rutin in obstructive nephropathy were likely due to anti-inflammatory effects and inhibition of TGF-β1/Smad3 signaling.