目的：探讨原花青素(PAC)是否通过Nrf2/GPX4通路改善视网膜色素上皮(RPE)细胞铁死亡及其对干性年龄相关性黄斑变性(ARMD)的保护作用。

方法：通过体外H₂O₂刺激的人RPE细胞(ARPE-19)模型和体内碘酸钠(NaIO₃)诱导的干性ARMD动物模型，评估PAC对铁死亡的保护作用。采用CCK-8法检测细胞活力，Calcein-AM/PI染色检测细胞死亡，脂质过氧化(LPO)检测试剂盒测定LPO水平，CM-H2DCFDA检测细胞内活性氧(ROS)水平，MitoSOX探针检测线粒体ROS水平，JC-1染色评估线粒体膜电位变化，Western Blot检测Nrf2通路相关蛋白(Nrf2、GPX4、HO-1)表达水平，视网膜铺片评估RPE结构与功能，苏木精-伊红(HE)染色观察大鼠视网膜形态变化，视紫红质(rhodopsin)和视蛋白(opsin)染色评估视网膜视功能，TUNEL染色检测视网膜细胞凋亡。

结果：H₂O₂加重ARPE-19铁死亡，表现为Fe²⁺、ROS和LPO水平升高。PAC预处理通过激活Nrf2/GPX4通路改善线粒体功能，降低细胞内Fe²⁺、ROS和LPO水平，抑制RPE细胞铁死亡。在NaIO₃诱导的干性ARMD模型中，PAC和铁死亡抑制剂Fer-1可逆转视网膜Nrf2/GPX4表达下调，减轻视网膜细胞死亡。

结论：PAC通过Nrf2/GPX4通路抑制铁死亡，为视网膜退行性疾病提供了潜在治疗策略。

METHODS: The protective effects of PAC against ferroptosis were evaluated using an in vitro model of H₂O₂-stimulated human RPE cells(ARPE-19)and an in vivo dry ARMD animal model induced by sodium iodate(NaIO₃). CCK-8 assay was applied to assess cell viability. Calcein-AM/PI staining was applied to determine the level of cell death. Lipid peroxidation(LPO)levels were measured using a lipid peroxidation assay kit. CM-H2DCFDA was used to detect the level of reactive oxygen species(ROS)in cells. MitoSOX probe was employed to measure the mitochondrial ROS level. JC-1 staining was used to evaluate the changes in mitochondrial membrane potential. Western Blot was performed to detect the expression levels of proteins(Nrf2, GPX4, and HO-1)related to the Nrf2 pathway. Retinal flat mounts were used to evaluate the structure and function of RPE. Hematoxylin and eosin(H & E)staining was applied to assess the morphological changes in rat retinas. Rhodopsin and opsin staining was used to evaluate visual function in the retina. TUNEL staining was employed to detect apoptosis in retinal cells.

RESULTS: H₂O₂ exacerbates ferroptosis in ARPE-19 cells, as evidenced by elevated levels of Fe²⁺, ROS, and LPO. PAC preconditioning ameliorates mitochondrial function, reduces intracellular Fe²⁺, ROS, and LPO levels, and suppresses ferroptosis in RPE cells via activation of the Nrf2/GPX4 signaling pathway. In a NaIO₃-induced dry ARMD model, both PAC and the ferroptosis inhibitor Fer-1 reverse the downregulation of retinal Nrf2/GPX4 expression and attenuate retinal cell death.

CONCLUSION:PAC inhibits ferroptosis via the Nrf2/GPX4 pathway, offering a novel potential therapeutic strategy for retinal degeneration.