Fortunellin attenuates sepsis-induced acute kidney injury by inhibiting inflammation and ferroptosis via the TLR4/NF-κB pathway.

Objective: To investigate the potential protective effect of fortunellin in sepsis-induced acute kidney injury (AKI) and its underlying mechanisms.

Methods: Lipopolysaccharide (LPS)-treated human kidney proximal tubular epithelial (HK-2) cells were used as a cell model and sepsis-induced AKI was induced by cecal ligation and puncture (CLP) surgery in mice. Cell Counting Kit-8 (CCK8) assays and flow cytometry analysis were performed to examine the viability of HK-2 cells. Enzyme-linked immunosorbent assay (ELISA) was performed to investigate the content of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interleukin-1 beta (IL-1β) and . The levels of malondialdehyde (MDA), superoxide dismutase (SOD), glutathione (GSH), and free iron (Fe) were measured as indicators of ferroptosis. The phosphorylation levels of Interleukin-1 Receptor-Associated Kinase 4 (p-IRAK4), p65 (p-65), and inhibitor of kappa B alpha (p-IκBα) were detected by western blot as an indication of nuclear factor kappa-B (NF-κB) pathway activation.

Results: Our cell and animal experiments revealed that fortunellin exhibits significant anti-inflammatory and cytoprotective properties. Fortunellin counteracted LPS-induced cellular damage in HK-2 cells, enhancing cell survival and suppressing the secretion of pro-inflammatory cytokines. Additionally, fortunellin demonstrated potent antioxidant effects, reducing MDA and Fe levels while increasing SOD activity and GSH content. The protective effect of fortunellin was further corroborated in the mouse model of sepsis-induced AKI. Notably, fortunellin suppressed activation of the TLR4/NF-κB pathway in the AKI model, as evidenced by decreased levels of p-p65 and p-IκBα proteins.

Conclusion: Fortunellin ameliorates inflammation and oxidative stress in sepsis-induced AKI, possibly through the modulation of the TLR4/NF-κB pathway. These findings suggest fortunellin's potential as a therapeutic agent for sepsis-associated AKI.