线粒体能量代谢指标与糖尿病视网膜病变的潜在关系OA

Objective To explore the potential relationship between the mitochondrial intima 44 homologue(TIMM44)and diabetic retinopathy(DR).Methods The human retinal pigment epithelial(RPE)cell line ARPE-19 was divided into a blank group,a mannose group,a high glucose(HG)group,a HG+TIMM44 group,and a HG+TIMM44+RS-VA405 group.Cell viability was detected by the CCK-8 assay kit,and mitochondrial membrane potential was measured by the JC-1 assay kit.After human retinal endothelial cells were co-cultured with conditioned medium from different groups of ARPE-19 cells,the angiogenesis in the human retinal endothelial cells in each group was assessed.Twenty-four C57BL/6J mice were randomly divided into a control group,a streptozotocin(STZ)group,a STZ+TIMM44 group,and a STZ+TIMM44+RSVA405 group.Reactive oxygen species(ROS)levels,ATP synthase activity,and relative mitochondrial DNA(mtDNA)copy numbers in cells or mouse retinal tissues in each group were detected by assay kits and quantitative real-time polymerase chain reaction.The expressions of TIMM44,serine/threonine kinase AMP-activated protein kinase(AMPK)/mammalian target of rapamycin(mTOR),and mitochondrial dysfunction related proteins were detected by west-ern blot.Results Compared with the HG group,the ARPE-19 cell viability,ATP synthase activity,mtDNA copy number,JC-1 ratio,and p-mTOR protein levels in the HG+TIMM44 group significantly increased(all P<0.05),while the ROS levels and the protein expression of cleaved caspase3,cyt-c,and p-AMPKsignificantly decreased(all P<0.05).The cell viability,ATP synthase activity,mtDNA copy number,JC-1 ratio,and Bcl-2 protein expression in ARPE-19 cells in the HG+TIMM44+RSVA405 group were significantly downregulated,while the ROS levels and the protein expression of cleaved caspase 3,cyt-c,and p-AMPK were significantly upregulated compared to the HG+TIMM44 group(all P<0.05).Compared with the HG group,the number of vascular branches formed by human retinal endothelial cells in the HG+TIMM44 group was signifi-cantly downregulated(P<0.05).The number of vascular branches formed by human retinal endothelial cells in the HG+TIMM44+RSVA405 group was significantly upregulated compared to the HG+TIMM44 group(P<0.05).Compared with the STZ group,the STZ+TIMM44 group showed significantly upregulated mouse retinal thickness,ATP synthase activity,mtDNA copy number,and Bcl-2 protein expression and significantly downregulated ROS levels(all P<0.05).The mouse retinal thickness,ATP synthase activity,mtDNA copy number,and Bcl-2 protein expression in the STZ+TIMM44+RSVA405 group were significantly downregulated,while ROS levels were significantly upregulated compared to the STZ+TIMM44 group(all P<0.05).Conclusion TIMM44 improves RPE mitochondrial dysfunction induced by HG exposure in vitro and in vivo by inhibiting the AMPK/mTOR signaling pathway.