Fig. 9

Application of EVs in FEC hydrogel in disc degeneration in vivo. A Diagrammatic sketch of the in vivo disc degeneration model. (B) The MRI, X-ray and fluorescent images of rat tail in different groups at weeks 4 (4 W) and weeks 8 (8W). C The MRI grade was assessed based on the MRI images. D The %DHI of disc was calculated based on the X-ray images. E The mean fluorescence intensity in the EVs and EVS@FEC group was quantified based on the fluorescent images. F, G Hematoxylin and eosin (HE), Safranin O-fast green (S–O), and Masson staining of the disc in different groups F and the corresponding histological grades (G). Data were presented as mean ± SD of six independent replicates. P > 0.05 (ns, not significant), *P < 0.05, **P < 0.01, and ***P < 0.001