Abstract
This study aimed to investigate the potential protective effects of riociguat, a soluble guanylyl cyclase (sGC) stimulator, on kidney function and structure in rats with acute kidney injury (AKI) induced by the chemotherapeutic drug doxorubicin (DX). Rats were subjected to a single intraperitoneal injection of DX (13.5 mg/kg) on the 5th day, either alone or in combination with low-dose riociguat (3 mg/kg/day), or high-dose riociguat (10 mg/kg/day) for 8 consecutive days. Various markers related to kidney function, oxidative stress, and inflammation were measured in plasma and urine. Kidney tissues were examined histopathologically. DX-induced nephrotoxicity was characterized by increased plasma urea, creatinine, uric acid and neutrophil gelatinase-associated lipocalin (NGAL). DX also decreased creatinine clearance and albumin levels and increased urinary N-acetyl-β-D-glucosaminidase (NAG) activity. Furthermore, DX increased the inflammatory markers interleukin 1 beta (IL-1 β), interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-α). DX further induced oxidative stress injury evidenced by decreased glutathione reductase (GR) activity, total antioxidant capacity (TAC), superoxide dismutase (SOD) and catalase levels and increased malondialdehyde (MDA) levels. Concomitant treatment with riociguat ameliorated these DX-induced changes with parallel histopathological improvements but the effects were more favorable with high-dose riociguat. The observed renoprotective effects of riociguat can be partly attributed to the anti-inflammatory and anti-oxidant properties of this drug.