Based on the nuclear factor E2-related factor 2 (Nrf2)/nuclear factor kappa B inhibitor alpha (IκB-α)/nuclear factor-kappa B (NF-κB) signaling axis, this study explored the protective effects of quercetin on lipopolysaccharide (LPS)-induced acute kidney injury (AKI) in rats.

A total of 60 SD rats were randomly divided into control group, model group, dexamethasone (DEX) group, quercetin high dose (100 mg·kg^-1) experimental group and quercetin low (10 mg·kg^-1) dose experimental group, with 12 rats in each group. Except for the control group, all other groups received intraperitoneal injection of LPS (10 mg·kg^-1) to prepare an AKI rat model. Enzyme-linked immunosorbent assay was used to detect serum levels of cystatin C (CysC), kidney injury molecule-1 (KIM-1) and inflammatory factors; renal tissue pathological changes were observed, and levels of myeloperoxidase (MPO), catalase (CAT) and 4-hydroxynonenal (4-HNE) in renal tissues were measured by colorimetry; immunohistochemistry was used to detect protein relative expression levels of Nrf2, IκB-α and NF-κB.

The levels of CysC in control group, model group, quercetin high dose group, low dose group and DEX group were (93.18±8.29), (317.58±12.26), (132.73±10.52), (182.91±10.63) and (153.29±10.14) ng·mL^-1, respectively; levels of KIM-1 were (12.39±1.79), (52.19±4.26), (26.83±3.89), (35.71±4.03) and (29.07±4.12) pg·mL^-1, respectively; MPO were (72.52±8.23), (177.95±9.14), (116.37±8.93), (136.52±9.37) and (121.81±9.02) pg·mL^-1, respectively; CAT contents were (60.73±8.12), (17.92±8.32), (38.41±8.73), (29.72±7.95) and (36.68±9.26) U·mL^-1, respectively; 4-HNE were (59.82±7.38), (179.63±9.41), (97.38±8.83), (116.91±9.17) and (98.56±8.79) nmol·L^-1, respectively. The levels of tumor necrosis factor-α (TNF-α) were (8.96±2.69), (58.27±5.13), (19.14±4.82), (39.56±5.37) and (16.38±4.11) pg·mL^-1, respectively; IL-1β were (15.62±3.58), (52.09±5.76), (29.47±4.61), (36.17±5.23) and (25.76±4.29) pg·mL^-1, respectively; IL-6 were (10.46±2.89), (71.14±6.53), (21.93±5.57), (33.28±5.96) and (19.12±5.61) pg·mL^-1, respectively. The intergrated optical density (IOD) of Nrf2 protein were 92.56±6.13, 45.09±6.97, 73.22±6.02, 63.52±6.73 and 68.29±6.51; IκB-α protein IOD values were 85.62±5.75, 42.83±6.29, 70.12±6.51, 61.45±6.87 and 78.77±6.32; the IOD values of NF-κB p65 protein were 43.28±4.92, 87.59±6.35, 55.79±5.32, 68.83±6.13 and 49.18±5.08, respectively. There were significant differences in the above indexes between the control group and the model group, between the model group and the quercetin high and low dose groups, and the DEX group (all P<0.05).

Quercetin may alleviate inflammation and oxidative stress damage by regulating the expression of Nrf2/IκB-α/NF-κB signaling axis, thereby playing a protective role against LPS-induced acute kidney injury.