Objective: To investigate the anti-infection and bone repair effects of cationic liposome-encapsulated vancomycin combined with the nano-hydroxyapatite/chitosan/konjac glucomannan (n-HA/CS/KGM) composite scaffold in vivo.
Methods: Fifty-one 6-month-old New Zealand white rabbits, weighing 1.5-3.0 kg, were selected to prepare chronic infectious tibia bone defect model by using Staphylococcus aureus. After 4 weeks, 48 survival rabbits were randomly divided into 4 groups (n=12). After debridement, defect was treated with nothing in group A, with n-HA/CS/KGM composite scaffold in group B, with vancomycin and n-HA/CS/KGM composite scaffold in group C, and with cationic liposome-encapsulated vancomycin and n-HA/CS/KGM composite scaffold in group D. After 8 weeks of treatment, general observation, X-ray, HE staining, the bacterial culture, and the measurement of the longest diameter of bone defect were done.
Results: At 4 weeks after modeling, 48 rabbits were diagnosed as having osteomyelitis, including periosteal new bone formation, destruction of bone, and soft tissue swelling. The Norden score was 3.83 +/- 0.52. At 8 weeks after treatment, sinus healed in groups C and D, but sinus was observed in groups A and B; the gross bone pathological scores of group D were significantly better than those of groups A and B (P < 0.05). Bone defects were repaired completely in group D, the results of the longest diameter of bone defects in group D was significantly better than those in the other 3 groups (P < 0.05). New bone formation was observed in groups C and D, but periosteal reaction and marrow low-density shadow were observed in groups A and B; Norden score in group D was significantly better than those in groups A, B, and C (P < 0.05). HE staining showed that there were a large number of trabecular bone formation and fibrosis, with no obvious signs of infection in groups C and D, but neutrophil accumulation was observed in groups A and B; Smeltzer scores in groups C and D were significantly better than those in groups A and B (P < 0.05). Bacteriological results showed higher negative rate in groups C and D than in groups A and B (P < 0.05).
Conclusion: Cationic liposome-encapsulated vancomycin and n-HA/CS/KGM composite scaffold can be a good treatment for infectious bone defects in rabbits, providing a new strategy for the therapy of bone defects in chronic infection.