目的：探究成纤维细胞生长因子21(FGF21)对高糖诱导的视网膜色素上皮(RPE)细胞氧化应激损伤的影响及其分子机制。

方法：通过GEO数据库中的小鼠视网膜组织单细胞测序数据，分析 FGF21受体FGFR1在RPE细胞中的表达丰度，培养人ARPE-19细胞系，随机分为对照组、高糖组(30 mmol/L 葡萄糖)、高糖+ FGF21类似物处理组，并设置siFGFR1处理组及PI3K抑制剂处理组，CCK8检测不同处理组细胞的活力变化，利用DCFH-DA荧光探针，结合免疫荧光染色及流式细胞术检测不同处理组细胞中的ROS水平，对高糖组及高糖+FGF21组的细胞进行转录组测序检测，分析PI3K/Akt信号通路富集程度，采用免疫印迹法检测PI3K/Akt信号通路相关蛋白的磷酸化水平。

结果：单细胞测序发现糖尿病模型小鼠视网膜中FGF21受体FGFR1在RPE细胞特异性高表达。体外实验中，高糖(30 mmol/L)处理使ARPE-19细胞活力下降49.7%，并诱导活性氧水平升高约2倍； 而FGF21类似物(60 ng/mL)干预可恢复细胞活力，并降低高糖诱导的ROS升高。机制研究表明，敲低FGFR1可抑制FGF21的抗氧化应激作用。进一步的分子机制验证显示，高糖处理显著抑制了PI3K/Akt信号通路的磷酸化(p-Akt与p-PI3K水平分别降低33.9%与36.6%)，而FGF21有效逆转了这一抑制效应，使p-Akt与p-PI3K表达均恢复。使用PI3K抑制剂LY294002可抑制FGF21的细胞保护作用，显著提升ROS阳性细胞率，证实PI3K/Akt通路是FGF21发挥作用的必要下游机制。

结论：FGF21通过受体FGFR1激活PI3K/Akt信号通路，减轻高糖诱导的RPE细胞氧化应激水平，减少细胞损伤。

METHODS:Single-cell sequencing data from the GEO database were analyzed to determine the expression profile of the FGF21 receptor FGFR1 in RPE cells. Human ARPE-19 cells were cultured and randomly assigned to control, high glucose(30 mmol/L), and high glucose+FGF21 analog treatment groups, with additional siFGFR1 and PI3K inhibitor groups. Cell viability in different treatment groups was assessed using CCK-8 assay, intracellular reactive oxygen species(ROS)levels were quantified using DCFH-DA fluorescent probing combined with immunofluorescence staining and flow cytometry. Transcriptome sequencing was performed on cells from the high glucose group and high glucose+FGF21 group to analyze the enrichment level of the PI3K/Akt signaling pathway. Western blotting was performed to detect phosphorylation levels of PI3K/Akt pathway components.

RESULTS:Single-cell sequencing revealed specific expression of FGFR1 in RPE cells of retinal tissues from diabetic model mice. Under In vitro experiments, high glucose(30 mmol/L)exposure reduced ARPE-19 cell viability by 49.7% and increased ROS levels by approximately 2-fold. Whereas treatment with the FGF21 analog(60 ng/mL)restored cell viability and attenuated high glucose-induced ROS accumulation. Mechanistic studies demonstrated that FGFR1 knockdown inhibited the antioxidative stress of FGF21. Further validation of the molecular mechanism revealed that high glucose significantly suppressed the PI3K/Akt pathway activation(the levels of p-Akt and p-PI3K were decreased by 33.9% and 36.6%, respectively), while FGF21 effectively reversed this inhibitory effect and restored the expression of p-Akt and p-PI3K. Treatment with the PI3K inhibitor LY294002 inhibited the cytoprotective effect of FGF21 and significantly increased the ROS-positive cells, these findings confirm that PI3K/Akt signaling is indispensable downstream mechanism for FGF21 to exert its effects.

CONCLUSION:FGF21 alleviates high glucose-induced oxidative stress and cellular injury in RPE cells by activating the PI3K/Akt signaling pathway through its receptor FGFR1.