Effect of membrane bone wound healing by hyperbaric oxygen treatment

Method: Thirty-two adult Wistar rats were divided into HBO group, control group, normobaric oxygen group (NBO) and hyperbaric air group (HBA). Bone defect of 3.8mm diameter was prepared on the parietal bone in all groups. HBO and HBA groups were placed pure oxygen or air under 2.5ATA for 120minutes/day. NBO groups were placed pure oxygen under 1 ATA for 120minutes/day. These treatments were performed 5 days a week, and repeated for 2 weeks. No treatment was taken in control group. All animals were sacrificed at 14 days after surgery. The defects were analyzed histologically. In histologically analysis, specimen was stained by hematoxylin and eosin. The stained sections were divided for histomorphometric measurements in the central area of the defect, 300µm back of the central area, and 600µm back of the central area. Bone regenerated areas were quantitatively calculated by the percentage of the cross-sectional area of new bone in the cross-sectional area of defect. To evaluate bony maturity, the numbers of nucleated cells were counted in the new bone areas.

Result: New bone cross-sectional area in the HBO group was significantly greater than that in the other groups (HBO: mean±SD 38.5±12.1%, control: 17.5±8.9%, HBA: 16.8±7.6%, NBO: 16.3±11.0%). There were no significant differences in the numbers of nucleated cells among the groups (HBO: mean±SD 1002.1±151.5/mm², control: 1547.6±440.0/mm², HBA: 1597.0±245.1/mm², NBO: 1358.6±151.6/mm²).

Conclusion: In this study, we demonstrated that HBO promoted bone wound healing in a rat calvarial bone defect model. HBO may be considered as a therapeutic option for orofacial bone fracture healing.