AMPK/mTOR信号通路介导的自噬在模拟高海拔视网膜病变中的作用OA

Objective To investigate the function of autophagy regulated by the AMP-activated protein kinase(AMPK)/mammalian target of rapamycin(mTOR)signaling pathway in simulated high-altitude retinopathy(HAR)and to explore its potential mechanisms.Methods Male C57BL/6 mice aged 6～8 weeks were employed.Mice in the model group were exposed to a hypobaric hypoxia chamber for 24 hours to simulate an altitude of approximately 5 000 m,and those in the control group were maintained under normal conditions.Histopathological changes in retinal tissues were assessed using hematoxylin-eosin staining.Reactive oxygen species levels were detected by dihydroethidium fluorescence staining.The expression of 8-OHdG in retinal tissue was examined by immunofluorescence.Western blotting analysis was performed to evaluate apoptosis-related proteins,including Bcl-2,Bax,and cleaved caspase-3(C-caspase 3),as well as key components of the AMPK/mTOR signaling pathway,including AMPK,mTOR and their phosphorylated forms.In addition,the expression of autophagy-related proteins LC3B and P62 was assessed by Western blotting and further con-firmed by immunofluorescence.Results Compared with the control group,mice exposed to simulated high-altitude conditions exhibited marked pathological alterations in retinal tissues.Dihydroethidium fluorescence staining revealed a significant increase in reactive oxygen species levels in the model group.Immunofluores-cence analysis showed a marked elevation of 8-OHdG expression.Western blotting results demonstrated sig-nificantly increased expression of Bax and C-caspase 3,indicating enhanced apoptotic activity.Phosphoryla-tion of AMPK was reduced,whereas phosphorylation of mTOR was increased in the model group.Moreover,LC3B expression was decreased and P62 expression was accumulated,suggesting a disturbance of autophagic flux.Conclusion Dysregulation of AMPK/mTOR-mediated autophagy may represent an important molecular mechanism underlying HAR.