ABSTRACT
Objective To confirm the vancomycin loaded gelatin/β-TCP composite porous scaffolds could be used as sustained-release system,and investigate its efficiency of eliminating infections and repairing bone defects for the treatment of infected bone defects in rabbit.Methods The biodegradable gelatin sponge containing different contents (0,10％,30％,50％) of β-tricalcium phosphate ceramic (β-TCP) was prepared for the controlled-release of vancomycin and labeled with G-0 TCP,G-10 TCP,G-30 TCP and G-50 TCP respectively.Examinations of scanning electron microscopy,porosity analyses and mechanical test were performed.The K-B method was used to investigate the controlled release of vancomycin.Chronic Methicillin-resistant Staphylococcus aureus osteomyelitis models of rabbit were established.After thorough debridement,the infected bone defects were treated in four different groups:blank control group,G-0 TCP group,G-10 TCP group,and G-30 TCP group.At 4 and 8 weeks after implantation,X-ray and histological examinations were carried out to investigate the efficiency of eliminating infections and repairing bone defects.Results The prepared gelatin/β-TCP scaffold exhibited a homogeneously interconnected-3-D porous structure.And the β-TCP granules were localized evenly on the walls of the composite scaffold.There were no significant differences in the pore size of different scaffolds.However,the β-TCP granules can improve the interconnection.The porosity exhibited an obvious increase in G-10 TCP and G-30 TCP composite scaffolds compared with G-0 TCP scaffold.In contrast,too high content of β-TCP granules decreased the porosity.And the porosity exhibited an obvious reduction in the G-50 TCP composite scaffold.The compressive modulus of the vancomycin loaded scaffolds increased with the increase of the β-TCP amount.The scaffold G-0 TCP exhibited the longest duration of vancomycin release and the duration reached 8 weeks.With the increased content of β-TCP granules,the release duration shortened obviously.Compared with the G-50 TCP composite scaffold,the G-10 TCP and G-30 TCP composite scaffolds revealed a better controlled release of the drugs,and the total amount of the drugs was released within 7 weeks.However,the total amount of vancomycin released from the G-50 TCP composite scaffold lasted for 3 weeks.In the treatment of chronic MRSA osteomyelitis of rabbits,the G-30 TCP composite scaffold showed a better performance in the eliminating infections and bone defects repair.At 8 weeks after implantation,signs of osteomyelitis,including osteolysis,development of periosteal reactions,and sequestral bone formation were observed in the animals of blank control group.Signs of infection were absent in other treatment group.In the group treated with G-30 TCP composite scaffold,the bonedefects were repaired completely at 8 weeks after implantation.However,in the groups treated with G-0 TCP and G-10 TCP composite scaffold,the bone defects were not repaired.Conclusion The composite scaffolds could achieve local therapeutic drug levels over an extended duration.And the gelatin with 30％ β-TCP granules composite scaffold had optimal porosity,interconnection,mechanical properties and controlled release performances.It exhibited good performances in infection control and bone defect repair in the chronic MRSA osteomyelitis model.