Obacunone Relieves Obstructive Nephropathy Fibrosis By Regulating Nrf2-GPx4-Mediated Ferroptosis

Objective: To study the effect of obacunone treating interstitial fibrosis in obstructive nephropathy and its mechanism.Methods: 30 SPF-grade C57BL/6 mice were randomly divided into sham surgery group,model group,obacunone low-dose group(10 mg/kg/d),obacunone high-dose group(40 mg/kg/d)and irbesartan group(positive drug control,20mg/kg/d).And obstructive nephropathy UUO model was established.Postoperative intraperitoneal injection was administered once daily for 7consecutive days,and equal volumes of normal saline were given to the sham and model groups.On the 7th postoperative day,mice were anesthetized and sacrificed,their bloods and kidneys were collected for subsequent experiments.The indicators of mouse serum,including malondialdehyde and superoxide dismutase levels,and the content of ferrous ions in kidney tissue were detected with corresponding kits.The tissue sections were stained with HE and Masson to observe the structural changes of the kidney.The expressions of related indicators were detected by immunohistochemistry,Western blot and quantitative real-time PCR.The related indicators about fibronectin,alphasmooth muscle actin,nuclear factor erythroid 2-related factor 2,glutathione peroxidase 4 and recombinant solute carrier family 7,member 11.In order to further verify the relevant mechanism of obacunone,the UUO model of obstructive nephropathy was established again,24 mice were randomly divided into sham surgery group,model group,obacunone group(40 mg/kg/d),obacunone with Nrf2 inhibitors(obacunone 40 mg/kg/d +ML385 30 mg/kg/d).Postoperative intraperitoneal injection,the interval between obacunone and Nrf2 inhibitor was 2 hours,and the remaining administration method was the same as above.The levels of serum MDA and SOD were detected.Tissue sections were stained with Sirius Red to observe fiber deposition.The expressions of Fibronectin,α-SMA,Nrf2,GPx4 were detected by Western blot and RT-q PCR.Results: Compared with the model group,the content of ferrous ions and MDA of mice in the low and high dose groups of obacunone were significantly reduced,SOD was significantly increased,the degree of renal tissue fibrosis and fibrosis index were significantly reduced,and the expression of Nrf2 and GPx4 in the kidney tissue of mice in the low and high dose group of obacuonone was significantly increased.Compared with the high-dose group of obacuonone,the MDA was significantly increased,the SOD was significantly reduced,the degree of fibrosis and fibrosis indexes of renal tissues were significantly increased,and the expression of Nrf2 and GPx4 was significantly reduced.Conclusion: 1.Obacunone can delay the progression of renal interstitial fibrosis in UUO mice;2.Obacunone delay the progression of renal interstitial fibrosis by regulating Nrf2-GPx4 signaling pathway by activating Nrf2.