Influence of hyperbaric oxygen on the initial stages of bone healing

Abstract

Objective: The objective of this study was to evaluate, in a rat model, the effect of hyperbaric oxygen (HBO) on the healing of normal bone on day 7.

Study design: Forty male rats were used, equally divided into two groups based on treatment and time of sacrifice: the control group had bone defects created; and the HBO group had bone defects and received HBO. HBO sessions were conducted daily, at 2.5 atmosphere absolute for 90 minutes, and the animals were euthanized after 1, 3, 5, or 7 days. Bone density, bone neoformation, and expression of Runt-related transcription factor 2 (Runx2) and tartrate-resistant acid phosphatase were evaluated.

Results: Computed tomography analysis revealed significant differences only at 3 days (P=.01) between the control and HBO groups. HBO treatment accelerated the initial events of bone repair, resulting in improved bone neoformation. Increased expression of Runx2 was observed, especially on days 5 and 7 in the HBO group, although not significantly. There was no significant difference (P=.74) in the number of tartrate-resistant acid phosphatase-positive osteoclasts between the control and HBO groups on day 7.

Conclusions: These results suggest that exposure to HBO enhances bone anabolism, reduces inflammation, and accelerates bone healing, with positive results in bone neoformation. Therefore, the aim of this study was to evaluate the effect of HBO on the healing of experimental defects created in normal bone, on the first 7 days, in a rat model.