Fig. 4

Promotion of in vivo retinal angiogenesis and remodeling by exosomes of M2 microglia. A Flow chart describes the in vivo establishment of the OIR mouse model. B Three-dimensional view of a frozen retinal section of OIR mouse showing exosome uptake in vivo. Scale bar = 50 μm. C, D Retinal flat mounts of C57BL/6J mice after OIR induction at P17 and intravitreal injection of M0-exo, M2-exo, or PBS at P12; yellow indicates the avascular area. Compared with the PBS or M0-exo group, the M2-exo group demonstrated significantly reduced avascular region and abnormal proliferating vessels. *p < 0.05, **p < 0.01***p < 0.001; n = 5. Scale bar = 200 μm. E Retinal flat mounts after tail vein injection of EdU in OIR mice. Effects of M2-exo on cell proliferation are demonstrated as the highest EdU+ cell number. ***p < 0.001; n = 5. Scale bar = 200 μm