OBJECTIVES: To investigate the role of ferroptosis in diquat-induced acute kidney injury (AKI) and its molecular mechanisms. METHODS: Transgenic zebrafish models with Tg (Eco.Tshb:EGFP) labeling of the renal tubules and Tg (lyz:dsRed2) labeling of the neutrophils were both divided into control group, gentamicin (positive control) group, diquat poisoning group, ferroptosis inhibitor group. The indicators of kidney injury, inflammatory response, and ferroptosis were examined in the zebrafish, and the changes in expressions of voltage-dependent anion-selective channel protein 1 (VDAC1) and mitochondrial ferritin (FTMT) were detected using Western blotting. RESULTS: AKI induced by diquat exhibited a significant dose-effect relationship, and the severity of injury was proportional to the exposure concentration. Diquat also caused marked oxidative stress and inflammatory responses in the zebrafish models. Rhodamine metabolism assay and HE staining revealed significantly declined glomerular filtration function of the zebrafish as diquat exposure concentration increased. Immunofluorescence staining highlighted significant changes in the expressions of ferroptosis markers GPX4 and FTH1 in zebrafish renal tissues following diquat exposure. In diquat-exposed zebrafish, treatment with ferrostatin-1, a ferroptosis inhibitor, obviously upregulated GPX4 and downregulated FTH1 expressions and improved the metabolic rate of glucan labeled with rhodamine B. Diquat exposure significantly upregulated the expression of VDAC1 and FTMT in zebrafish, and the application of ferrostatin-1 and VBIT-12 (a VDAC1 inhibitor) both caused pronounced downregulation of FTMT expression. CONCLUSIONS Ferroptosis is a critical mechanism underlying diquat-induced AKI, in which VDAC1 and FTMT play important regulatory roles, suggesting their potential as therapeutic target for AKI caused by diquat.
Animals ; Zebrafish ; Ferroptosis/drug effects* ; Acute Kidney Injury/chemically induced* ; Diquat/toxicity* ; Animals, Genetically Modified ; Voltage-Dependent Anion Channel 1/metabolism* ; Ferritins/metabolism* ; Oxidative Stress

AIM: To investigate the effect of silymarin on homocysteine-induced cell viability and apoptosis in human umbilical vein endothelial cells (HUVECs). METHODS: Cell viability was analyzed by using MTT and LDH assay. Apoptotic cells were detected by using DNA fragmentation and flow cytometric analysis. The level of intracellular reactive oxygen species (ROS) and the potential of mitochondrial membrane were determined by flow cytometric assay. The activity of caspase-3, -6 and -9 were measured with microplate spectrofluorometer. Protein levels were examined by Western blotting. RESULTS: Treatment of cultured HUVECs with HCY for 48 h induced a significant decrease in cell viability, and the percentage of apoptosis increased to 76.8%. The level of intracellular ROS and activity of caspase-3, -6 and -9 enhanced, and the red/green ratios of mitochondrial membrane decreased. However, simultaneous treatment with silymarin exhibited cytoprotective effects, reduced formation of the DNA ladder, prevented the levels of Bax and Bcl-2 proteins and the accumulation of ROS as well as caspase-3, -6 and -9 activation, reconverted the potential of mitochondrial membrane, and the percentage of apoptosis/necrosis was significantly decreased to 12.7% in a dose-dependent manner. CONCLUSION: These results demonstrate that silymarin has the protective capacity to antagonize HCY-induced apoptosis in HUVECs. The antiapoptotic action of silymarin may be partially dependent on an anti-oxidative stress effects, inhibition of caspases activity, and maintenance of mitochondria function.