Objective To evaluate the in vitro sustained release properties of novel mesoporous silica microspheres (MSNs) loaded antibiotic/polyurethane (PU)/nano-hydroxyapatite (n-HA) scaffolds and their efficacy in the treatment of rabbit tibia infected bone defects.Methods The scaffolds loaded with 1 mg of levofloxacin mesoporous nanospheres/hydroxyapatite/polyurethane (1 mg Lev/n-HA/PU) and the polymethyl methacrylate (1 mg Lev/PMMA) loaded with 1 mg of levofloxacin were placed on the scaffolds, respectively. In 1 mL of simulated body fluid, the drug release amount was detected at different time points of 1 d, 2 d, 3 d, 4 d, 5 d, 6 d, 1 week (w), 2 w, 3 w. Twenty-four animal models of chronic osteomyelitis of the tibia were established, and they were divided into 4 groups. Animals in group a were simply debridement; group b was implanted with 1 mg Lev/PMMA; group c was implanted with n-HA/PU; group d was implanted with 1 mg Lev/n-HA/PU. X-ray, Micro CT and histology were observed at 6 W and 12 W postoperatively. To evaluate the efficacy of the new composite material in controlling infection, inducing osteogenesis, and treating chronic osteomyelitis.Results The 1 mg Lev/n-HA/PU group released more antibiotics than the 1 mg Lev/PMMA group (P<0.05), and the sustained release performance was better. X-ray showed that the simple debridement group showed local bone destruction and sequestrum formation. There was no obvious bone destruction in the 1 mg Lev/n-HA/PU group. There was no obvious local inflammatory reaction in the 1 mg Lev/n-HA/PU group. Micro CT found that the number of new bone trabeculae around the material in the 1 mg Lev/n-HA/PU group was significantly different from the other three groups (P<0.05).Conclusion The new antibiotic-loaded composite scaffold has good sustained-release performance, anti-infectious ability, osteoinductive ability, can effectively treat tibial infectious bone defect. |