Male Sprague-Dawley rats (6-8 weeks old; weighed from 210 to 230 g) were purchased from HFK Bioscience Co. Ltd. Rats were randomly assigned to four groups (n = 6 per group). The first was the control group, which were treated daily with 0.5 ml of 0.9% saline by intraperitoneal injection for 14 days, and there were three DOX model groups, which were treated three times weekly with 2.5 mg/kg of DOX by intraperitoneal injection for 14 weeks. At day 14, mice in the DOX model groups were infected through an intramyocardial injection of either control shNC or shMettl14 (1 x 10⁹ titer) at three distinct locations in the left ventricular free wall three times a week for 2 weeks, and they were treated daily with 30 mg/kg of ferroptosis inducer erastin (MedChemExpress, USA) through intragastric administration or vehicle control (Saline) for 2 weeks.

Male Sprague-Dawley rats (6-8 weeks old; weighed from 210 to 230 g) were purchased from HFK Bioscience Co. Ltd. Rats were randomly assigned to four groups (n = 6 per group). The first was the control group, which were treated daily with 0.5 ml of 0.9% saline by intraperitoneal injection for 14 days, and there were three DOX model groups, which were treated three times weekly with 2.5 mg/kg of DOX by intraperitoneal injection for 14 weeks. At day 14, mice in the DOX model groups were infected through an intramyocardial injection of either control shNC or shMettl14 (1 x 10⁹ titer) at three distinct locations in the left ventricular free wall three times a week for 2 weeks, and they were treated daily with 30 mg/kg of ferroptosis inducer erastin (MedChemExpress, USA) through intragastric administration or vehicle control (Saline) for 2 weeks.

For in vivo experiments, the eyes in each group (n = 6) were enucleated carefully and processed for indirect immunofluorescence in whole-mount or cross-section as previously described. For cryosections, the eyes (n = 3 retinae from 3 mice) were fixed in 4% PFA at room temperature for 15 min. The frozen samples were then sliced transversely (6 um) at -20. For retinal flat-mounts, the eyes (n = 3 eyes from 3 mice) were fixed in 4% PFA at room temperature for 15 min, and the retinae were dissected out as cups. Both cryosections and retinal cups were blocked with PBS containing 0.5% Triton-X100 and 5% BSA at 4 overnight and included with the anti-CD31 and anti-GPX4 (1:100, ab125066, Abcam) primary antibodies.