Effect Of Nrf2/GPX4 Pathway-based Regulation Of Ferroptosis On Renal Fibrosis

Objective: To investigate the role of Nrf2/GPX4 pathway in regulating ferroptosis in unilateral ureteral obstruction(UUO)mice and chronic kidney disease(CKD)on renal fibrosis,and to investigate the mechanisms and potential targets of renal fibrosis.Methods:1.In animal experiments,30 male C57BL/6 mice of SPF grade 6-8 weeks old were randomly divided into 6 groups: sham-operated group,UUO control group,Nrf2 agonist sulforaphane(SFN)group(25 mg/(kg-d)),ferroptosis inhibitor liproxstatin-1(Lip-1)group(10 mg/(kg-d)),irbesartan positive drug group(20 mg/(kg-d)),and GPX4 inhibitor GPX4-IN-3 group(20 mg/(kg-2d)).Five mice in each group were fed with normal chow for 1 week,and the mice in the latter four groups were injected with the drug intraperitoneally.The activity of superoxide dismutase(SOD)and malondialdehyde(MDA)were measured in mice.Renal tissues stained with HE and Sirius Red to observe the renal pathological changes.Western blot,RT-q PCR and immunohistochemistry were used to determine the expression of fibronectin(Fn),collagen-Ⅰ(Col-Ⅰ),α-smooth muscle actin(α-SMA),nuclear factor E2-related factor 2(Nrf2),glutathione peroxidase 4(GPX4),solute carrier family 7 member 11(SLC7A11),and nicotinamide adenine dinucleotide phosphate oxidase 4(NOX4)in mice kidney tissues.2.According to the results of kidney puncture specimens from CKD patients,they were divided into low-fibrosis group and high-fibrosis group,and the expression levels of Nrf2,GPX4 and α-SMA were measured by immunohistochemistry.Results:1.In animal experiments,compared with the UUO model group,the expression of SOD increased in the SFN,Lip-1,and Irbesartan groups,and the expression of MDA and fibrosis decreased,while the expression of GPX4-IN-3group showed decreased expression of SOD and increased expression of MDA and fibrosis.Compared with the control group and GPX4-IN-3 group,the expression of Nrf2,GPX4,and SLC7A11 in the renal tissues of SFN and Lip-1groups was increased(P < 0.05),and the expression of NOX4 in the renal tissues of SFN and Lip-1 groups was decreased(P < 0.05).2.The expression of α-SMA in paraffin sections of kidney tissues of patients in the low-fibrosis group was lower than that of patients in the high-fibrosis group,while the expression of GPX4 and Nrf2 was higher than that of patients in the high-fibrosis group by immunohistochemistry.Conclusion: In animal experiments,regulation of ferroptosis via the Nrf2/GPX4 pathway effectively improved the degree of renal fibrosis;in CKD patients,the degree of renal fibrosis correlated with the ferroptosis target of Nrf2/GPX4,providing a basis for clinical CKD antifibrosis.