Formononetin alleviated cisplatin-induced acute kidney injury by orchestrating renal tubular cell ferroptosis via PI3K/AKT/NRF2 pathway

Background Cisplatin chemotherapy is limited by its nephrotoxicity, which leads to acute kidney injury (AKI). Ferroptosis is a key pathogenic mechanism in cisplatin-induced AKI. Formononetin (FN), a natural isoflavone, has demonstrated antioxidant and renoprotective potential, but its role in modulating ferroptosis remains unclear. Methods A cisplatin-induced AKI model in mice and a cisplatin-injured HK-2 cell model were established. Kidney injury was assessed via serum creatinine, blood urea nitrogen, H&E staining, and Kim-1 expression. Ferroptosis was evaluated by measuring glutathione (GSH), malondialdehyde (MDA), iron deposition, lipid peroxidation, mitochondrial morphology, and the expression levels of GPX4, SLC7A11, FTH and FTL. The involvement of the NRF2 pathway was investigated using the inhibitor ML385 in vivo and siRNA in vitro . The role of the PI3K/AKT pathway was assessed using the inhibitor LY294002. Results FN treatment significantly improved renal function and attenuated tubular damage in cisplatin-induced AKI. It suppressed key features of ferroptosis, as shown by increased GSH, decreased MDA and iron levels, and preserved mitochondrial integrity. FN also reduced the oxidized lipids, and reversed the cisplatin-induced downregulation of SLC7A11 and GPX4. The renoprotective and anti-ferroptotic effects of FN were abolished by the NRF2 inhibitor ML385 in vivo and by siRNA in vitro . Furthermore, FN activated the PI3K/AKT pathway, and the PI3K inhibitor LY294002 blocked FN-mediated upregulation of NRF2 and GPX4. Conclusion FN protects against cisplatin-induced AKI by inhibiting ferroptosis. This effect is mechanistically associated with the activation of the PI3K/AKT pathway, which subsequently enhances NRF2 signaling and upregulates GPX4 expression. Our findings support FN as a potential candidate for further investigation in the prevention of cisplatin nephrotoxicity.