Fig. 5

Histological analysis of the distracted regenerates from four groups after consolidation for 2 (a, b) and 4 weeks (c, d). e H&E staining and Masson’s staining in the sham group. The distraction gaps in all four groups mainly consisted of various amounts of trabecular bone, fibrous tissue, and cartilaginous tissue. In PBS-treated samples, the distraction gaps showed increased fibrous and cartilaginous tissues and less trabecular bone in the center zone. With treatment of Exos or EPCs, the distraction gaps showed more mature trabecular bone and less fibrous and cartilaginous tissues. EPCs endothelial progenitor cells, Exo exosomes secreted by EPCs, PBS phosphate-buffered saline