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Protective Effects and Mechanism of Exosomes Overexpressing BDNF on Ischemic Retinal Injury
Received date: 2026-03-17
Revised date: 2026-05-07
Accepted date: 2026-08-13
Online published: 2026-08-17
Objective： To investigate the protective effect of exosomes derived from human 293T cells overexpressing brain-derived neurotrophic factor （BDNF） （293T-Exo） on retinal ischemic injury and its potential endocytic mechanism.Methods： Exosomes were isolated from the culture supernatant of BDNF-overexpressing 293T cells using ultracentrifugation combined with a kit method， and identified by transmission electron microscopy （TEM）， nanoparticle tracking analysis （NTA）， and Western blot. 293T-Exo was co-cultured with R28 cells， and cellular uptake was observed using fluorescence labeling. The endocytic mechanism was explored via intervention experiments using RGD peptide， heparin， and methyl-β-cyclodextrin （MBCD）. An oxygen-glucose deprivation （OGD） model in R28 cells was established to simulate ischemic injury in vitro. EdU incorporation assay and lactate dehydrogenase （LDH） release assay were used to evaluate the effects of 293T-Exo on cell proliferation and death. A retinal ischemia-reperfusion model was constructed in SD rats. After intravitreal injection of 293T-Exo， retinal apoptosis was detected by TUNEL staining， and the localization of exosomes in retinal ganglion cells （RGCs） was observed by immunofluorescence staining.Results： Typical exosome particles with a diameter of approximately 144.2 nm expressing CD9， CD63， CD81， and HSP70α were successfully isolated. 293T-Exo was taken up by R28 cells in a dose- and temperature-dependent manner. This process was significantly inhibited by RGD peptide and MBCD， and co-localization with Caveolin-1 was observed， suggesting an integrin-mediated caveolin-dependent endocytic pathway. Compared with the control group， 293T-Exo treatment significantly enhanced the proliferative capacity of R28 cells under OGD conditions and reduced cell mortality （P<0.05）. In vivo experiments showed that intravitreal injection of 293T-Exo significantly reduced the number of TUNEL-positive cells in all layers of the ischemic retina， especially in the RGC layer （P<0.05）， and the exosomes were mainly taken up by RGCs.Conclusion： 293T-Exo of overexpressing BDNF can be effectively taken up by retinal cells via an integrin-mediated caveolin-dependent endocytic pathway and exert significant neuroprotective effects in both in vitro and in vivo ischemic models， suggesting their potential application value as a cell-free therapeutic strategy for ischemic retinal diseases.
Key words： ; Retinal ischemia； ; Exosomes； ; Brain-derived neurotrophic factor； ; Endocytosis； ; Apoptosis
YAN Bojing, SUN Xiaowei, LI Genlin
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Protective Effects and Mechanism of Exosomes
Overexpressing BDNF on Ischemic Retinal Injury
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