Hyperbaric Oxygen Therapy Promotes Bone Healing in Patients with Maxillary Sinus Lateral Augmentation and Diabetic Mice Potentially through the Nrf2 Pathway.

OBJECTIVE

To assess the impact of hyperbaric oxygen (HBO) therapy on bone healing in dia-betic patients and explore potential mechanisms in an animal experiment.

METHODS

Four non-diabetic patients undergoing maxillary sinus lateral augmentation were assigned to either standard care (control group) or HBO treatment for 5, 6 or 9 weeks. Bone core samples were collected for immunochemistry during the preparation for implant insertion. Additionally, 12 db/db diabetic mice and 12 control mice with tibia defects were subjected to HBO treatment. After 7 days, the bone repair process was assessed using microcomputed tom-ography (microCT), histology, immunohistochemistry and Western blot analyses.

RESULTS

HBO improved bone formation in the implant areas of patients treated for 5, 6 and 9 weeks, increasing local vascular endothelial growth factor, bone morphogenetic protein-2 and osteocalcin expression. Diabetic mice exhibited impaired bone healing, but HBO-treated groups (diabetic or non-diabetic) showed enhanced new bone formation. Increased osteocalcin and runt-related transcription factor 2 and decreased tartrate-resistant acid phosphatase expression were detected. The nuclear factor erythroid-derived 2-related factor 2 (Nrf2) pathway and its downstream proteins catalase and heme oxygenase-1 were upregulated after HBO.

CONCLUSION

HBO enhances bone healing in both patients and diabetic mice, and is potentially mediated through the Nrf2 pathway.