miR-324 of sEVs released from osteoclast facilitates bone defect healing in vivo
(A) Schematic diagram shows the fabrication of sEV-modified scaffold and grafting of calvarial defect mice. (B) Representative general and coronal micro-CT images, H&E, Masson, and TRAP staining, and IHC of OCN in decalcified bone sections from mice treated with OC-sEVs, miR-NC-sEVs, miR-324-sEVs, and miR-324-sEVs + miR-324 inhibitor. Scale bars represents 2 mm in H&E staining, 50 μm in Masson, TRAP, and IHC staining. (C) Quantitative micro-CT analysis shows the bone volume density (BV/TV) and bone mineral density (BMD) of total defect repair area in indicated groups; n = 8. (D) Quantification analysis of bone formation ratio in indicated groups; n = 8. (E) Semiquantitative analysis of OCN in indicated groups; n = 8. (F and G) Quantitative analysis of the number of (F) osteoblasts (N.Ob) and (G) osteoclasts (N.Oc) on the cortical bone surface (BS) using IHC staining of OCN and TRAP staining in indicated groups. The data in the figures represent the averages ± SD. ∗p < 0.05, ∗∗p < 0.01, for differences between the treatment and control groups.