Urolithin B as a renoprotective agent against 5-fluorouracil-induced nephrotoxicity: Role of Nrf2/Keap1/HO-1, SIRT1/FOXO3, and NF-кB/TNF-α signaling pathways.

The clinical use of 5-fluorouracil (5-FU) in cancer patients has been associated with nephrotoxicity, which is greatly curbing its therapeutic application. The pathogenesis of 5-FU-induced nephrotoxicity is complex; however, oxidative stress-mediated inflammation is considered a central pathogenic factor. Urolithin B (UB), a product of ellagitannins, has recently been assigned diverse pharmacological activities due to its potent antioxidant and anti-inflammatory properties. Therefore, the current study explored the potential renoprotective effect of UB on 5-FU-induced nephrotoxicity in mice and illuminated its potential mechanistic pathways. In this study, administration of UB (50 and 100 mg/kg) mitigated 5-FU-induced elevated levels of kidney injury indices, including renal somatic index, serum creatinine, blood urea nitrogen, and serum cystatin C, that were concurrent with histopathological improvement. UB maintained renal oxidant/antioxidant balance and enhanced the nuclear factor-erythroid-2-related factor-2 (Nrf2)/heme oxygenase 1 (HO-1) as well as the silent information regulator factor 2-related enzyme 1 (SIRT1)/forkhead box O 3 (FOXO3) antioxidant protective responses. On the other hand, 5-FU-driven activation of the NF-кB/TNF-α inflammatory signaling was opposed by UB administration. Conclusively, UB protected against 5-FU-induced nephrotoxicity through dose-dependent antioxidant and anti-inflammatory effects. These effects are mediated mainly through upregulating Nrf2/HO-1 and SIRT-1/FOXO3 antioxidant responses with subsequent suppression of NF-κB inflammatory signaling.