A Preliminary Study On The Mechanism Of Ferroptosis In Obesity-related Glomerulopathy

Objective Aims: To establish a mouse model of obesity-related glomerulopathy(ORG),to investigate the pathological changes of kidney and iron death in mice fed high fat and high energy diet for 16 weeks.Methods: 30 C57 BL / 6 mice were randomly and equally divided into 2 groups,15 mice in each group: ORG group and control group were fed with high fat and high energy diet and normal diet respectively.The body mass of mice was recorded every week.All mice were killed and their kidneys were taken at the end of 16 weeks.HE staining and Masson staining were used to observe the pathological changes of kidney under light microscope.Ultrastructural changes of kidney in ORG mice were observed by transmission electron microscope.The expression of GPX4 m RNA was detected by real-time quantitative RT-PCR and semi-quantitative analysis was performed.The expression sites and levels of GPX4 and 4-HNE in kidney of mice were detected by immunohistochemical staining.The expression of GPX4 protein was detected by Western blot.The content of lipid peroxide and iron in kidney tissue was detected by colorimetry.Results The results were statistically processed by Graph Pad software.Results: Under light microscope,HE staining showed that the glomerulus volume of ORG group mice increased obviously,and Masson staining showed FSGS changes such as balloon adhesion and increased local segmental mesangial matrix.Tubule swelling,vacuolar degeneration and other changes,renal interstitial collagen fiber deposition.Transmission electron microscopy showed that the glomerular epithelial cells of the ORG model group showed foot process fusion and lipid droplet formation.At the same time,mitochondria showed characteristic changes of iron death: mitochondria were reduced and the cristae of mitochondria decreased or disappeared.Compared with the control group,the expression of 4-HNE in ORG group was increased,mainly in glomerulus.The differential expression of GPX4 was mainly localized in the tubular epithelial cells,and all the differences were statistically significant(P < 0.05).RT-PCR results showed that the expression of GPX4 m RNA in ORG model group was significantly lower than that in control group(P < 0.05).The expression level of GPX4 protein in ORG model group was lower than that in control group by Western blot(P < 0.05).Compared with the control group,the contents of MDA,4-HNE and iron in kidney tissue of ORG model group increased significantly(P < 0.05).Conclusion: ORG mice fed a high-fat high-energy diet for 16 weeks could reach the stage of O-FSGS.ORG mice kidney GPX4 expression levels decreased,MDA,4-HNE,tissue iron increased,The characteristic changes of iron death in mitochondria of kidney cells suggest that iron death mediated by GPX4 may be involved in the development of ORG.These studies are expected to lay a foundation for the further study of the pathogenesis of ORG and the possible therapeutic approaches.