Effects of exosomes on tendon-bone healing and the bone formation at the tendon-bone interface in a rat ALCR model. (A) Schematic representation of the ACLR surgical procedures in a rat ALCR model. (B) Representative IVIS images of the exosome retention in the surgical knee joints 48 h after local injection of IONP-Exos, BMSC-Exos, or PBS control into the bone tunnel. (C) The load-to-failure force of the femur-tendon graft-tibia complexes at 4 and 8 weeks after ACLR among the IONP-Exos, BMSC-Exos, or PBS groups. (D) Stiffness of the femur-tendon graft-tibia complexes at 4 weeks and 8 weeks after ACLR among the IONP-Exos injection, BMSC-Exos injection, and PBS injection groups. (E) Micro-CT images of the cross-sections of the tibial bone tunnels at 4 weeks and 8 weeks after ACLR. (F) Quantitative analysis of the cross-sectional bone tunnel area among the IONP-Exos, BMSC-Exos, and PBS groups. (G) Reconstructed 3-dimensional models of micro-CT images of newly formed bone at 4 weeks and 8 weeks after ACLR. (H) Quantitative results of new bone formation within the bone tunnel as measured by micro-CT at 4 weeks and 8 weeks after surgery. Micro-CT parameters: bone volume fraction (BV/TV); trabecular thickness (Tb. Th); trabecular number (Tb. N); trabecular separation (Tb. Sp); structure model index (SMI); bone mineral density (BMD). ACLR: anterior cruciate ligament reconstruction. micro-CT: micro-computed tomography. ∗P < 0.05; ∗∗P < 0.01; ∗∗∗P < 0.001.