Effects of FGF-2 with hyaluronic acid, BCP, hyperbaric oxygen therapy on bone healing in irradiated calvarial defects of rats

Abstract

Purpose: For irradiated patients, the healing capacity of irradiated bone decreases markedly. Therefore, rehabilitation for patients who experienced radiotherapy requires more attention. The purpose of this study was to evaluate the effect of the grafted materials and hyperbaric oxygen therapy (HBO) on the bone healing in experimentally created calvarial defects in irradiated rats.Materials & Methods: Sprague-Dawley rats (body weight about 300g, 4 weeks old, male) enrolled in the study were divided into the four groups. Rats were divided into the group with HBO and the group without HBO (NHBO). Each group had two subgroups which were FGF-2 with hyaluronic acid (HA) group and BCP block group according to the graft. Localized radiation with a single dose of 12 Gy radiation was applied to the calvarium. Four weeks after radiation, two symmetrical, circular defects of 6-mm-diameter were created in the parietal bones of animal. The left defect was left empty as a control and the right defect was filled with the materials mentioned above. During 4 weeks of healing, 1-hour HBO was performed for the HBO groups for 5 times a week. After these 4 weeks of healing, the rats were sacrificed. The calvarial specimens were harvested for histomorphometric and micro-CT analysis.Results: 1. FGF-2 with HA groups showed more new bone area compared with other groups. BCP block showed adverse effect on new bone formation. The effect of HBO on new bone area seemed minimal.2. FGF-2 with HA groups showed more new bone length than other groups. BCP block seemed to have adverse effect on new bone formation. The effect of HBO on new bone length seemed minimal.3. Generally, HBO groups showed more angiogenesis than NBO groups. However, when FGF-2 with HA was applied with HBO therapy, angiogenesis was not improved compared with HBO alone or FGF-2 with HA alone.Conclusion: Within the limitations of this study, HBO had beneficial effects on angiogenesis. However, the effect of HBO on bone regeneration seemed minimal in the irradiated rat model of the present study. It showed that FGF-2 with HA enhanced bone generation and angiogenesis, but its efficacy was decreased with HBO. BCP block did not show any beneficial effect on bone regeneration