Characterization of the Developing Lacunocanalicular Network During Fracture Repair

Fracture repair is a normal physiological response to bone injury. During the process of bony callus formation, lacunocanalicular network (LCN) formed de novo that evolves with remodeling. Our aim was longitudinal assessment development and evolution LCN during fracture repair. To this end, 45 adult wild-type C57BL/6 mice underwent closed tibial surgery. Fractured intact contralateral tibias were harvested after 2, 3, 6 weeks healing (n = 15/group). High-resolution micro–computed tomography (μCT) deconvolution microscopy (DV) approaches applied quantify lacunar number density from calluses bone. On histological sections, Goldner's trichrome staining used assess occupancy, fluorescein isothiocyanate visualize canalicular network, terminal deoxynucleotidyl transferase–mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL) examine osteocyte apoptosis. Analysis μCT scans showed progressive decreases in mean lacuna volume over time (−27% 2–3 weeks; −13% 3–6 weeks). Lacunar increased considerably between 2 3 (+156%). Correlation analysis performed, showing positive linear relationship trabecular thickness (R2 0.56, p < 0.001) an inverse 0.57, 0.001). Histology increases (+22% weeks, +51% occupancy new high (>90%), but old cortical within site appeared necrotic as it resorption. In conclusion, our data shows increase complexity demonstrates initiated early stages Further studies are needed address functional importance osteocytes healing, particularly detecting translating effects micromotion fracture. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf American Society for Bone Mineral Research.