Effects of Calcium Sulfate Combined with Platelet-rich Plasma on Restoration of Long Bone Defect in Rabbits

Background：The treatment for long bone defects has been a hot topic in the field of regenerative medicine.This study aimed to evaluate the therapeutic effects of calcium sulfate （CS） combined with platelet-rich plasma （PRP） on long bone defect restoration.Methods：A radial bone defect model was constructed through an osteotomy using New Zealand rabbits.The rabbits were randomly divided into four groups （n =10 in each group）：a CS combined with PRP （CS-PRP） group,a CS group,a PRP group,and a positive （recombinant human bone morphogenetic protein-2） control group.PRP was prepared from autologous blood using a two-step centrifugation process.CS-PRP was obtained by mixing hemihydrate CS with PRP.Radiographs and histologic micrographs were generated.The percentage of bone regenerated bone area in each rabbit was calculated at 10 weeks.One-way analysis of variance was performed in this study.Results：The radiographs and histologic micrographs showed bone restoration in the CS-PRP and positive control groups,while nonunion was observed in the CS and PRP groups.The percentages of bone regenerated bone area in the CS-PRP （84.60 ± 2.87%） and positive control （52.21 ± 4.53%） groups were significantly greater than those in the CS group （12.34 ± 2.17%） and PRP group （16.52 ± 4.22%） （P 〈 0.001）.In addition,the bone strength of CS-PRP group （43.l 0 ± 4.10%） was significantly greater than that of the CS group （20.10 ± 3.70%） or PRP group （25.10 ± 2.10%） （P 〈 0.001）.Conclusion：CS-PRP functions as an effective treatment for long bone defects through stimulating bone regeneration and enhancing new bone strength.