Influence of Platelet-Poor Plasma on Angiogenesis and Maintenance of Volume in Autogenous Bone Grafts.

PURPOSE: The aim of this study was to evaluate the effect of different storage media on angiogenesis and maintaining autogenous bone graft volume in rabbits. MATERIAL AND METHODS: Two grafts were removed bilaterally from the calvaria of 18 rabbits. One graft was removed and immediately fixed in the right mandibular angle (control group). The other graft was stored for 30 minutes in 1 of the following storage media (n = 6): saline solution (saline group), air exposure (dry group), or platelet-poor plasma (PPP group) and then retained by a screw in the right mandibular angle in the same animal. Four weeks later the animals were euthanized, and the grafted areas were harvested, fixed in 10% phosphate buffered formaldehyde solution, and embedded in paraffin. The 5-µm semi-serial sections were stained in hematoxylin and eosin and Mallory trichrome. RESULTS: Histologic analysis of all groups showed the bone graft was vascularized and well incorporated into the recipient site. The number of blood vessels decreased in the saline and dry groups compared with the control group (P < .03); in contrast, the number of blood vessels increased in the PPP group (P < .05). There were fewer osteoclasts in the saline group compared with the control group (P < .05). Furthermore, the saline group showed larger numbers of blood vessels than the dry group (P < .01). The PPP group showed larger bone graft volumes compared with the dry and saline groups (P < .01). In addition, the saline group showed larger bone graft volumes than the dry group (P < .01). CONCLUSIONS: PPP improved angiogenesis, maintained the volume of the autogenous bone graft, and was a better storage medium during the trans-surgical period than the dry and saline media.

Influence of hyperbaric oxygen on the initial stages of bone healing.

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.