Fig. 4

The composite hydrogels with GDF5-loaded microspheres significantly increased the chondrogenic level of NPSCs. (A) CCK-8 assay was used to detect the proliferation level of NPSCs and BMSCs under the four hydrogel-conditioned mediums at different time points. (B–E) RT-qPCR and western blot were used to detect the expression levels of phenotypic genes and proteins of NPSCs and BMSCs under the four hydrogel-conditioned mediums at 14 and 21 d. (n ≥ 3, *p < 0.05, **p < 0.01)