Objective As a bioactive material, the osteogenic activity of borate bioglass has been proved. To design a novel borate bioglass according to an improved formula and to investigate the effects of the borate bioglass on osteoblasts invitro for further research and potential cl inical appl ication. Methods The novel Na2O-K2O-MgO-CaO-P2O5-B2O3-SrO borate bioglass was prepared by melting process. The initial and secondary extracts were prepared according to ISO10993-12: 2007 respectively with different extract time of 0-24 hours and 24-48 hours. The osteoblasts (MC3T3-E1) of the 5th-15th passages from mouse were cocultured with the initial (initial extract group) and secondary (secondary extract group) extracts, respectively, to assess the effects of the borate bioglass on the cell prol iferation, protein synthesis, alkal ine phosphatase (ALP) activity, cell apoptosis, and cell migration; while α-MEM medium without addition of extract served as control group. Results The absorbance values at 450 nm were 0.356 0 ± 0.018 7, 0.331 0 ± 0.025 4, and 0.204 0 ± 0.013 8 in initial extract, secondary extract, and control groups, respectively, showing significant differences among 3 groups (P lt; 0.05). The total protein contents were (382.847 ± 9.521), (226.071 ± 5.847), and (220.248 ± 8.213) U in initial extract, secondary extract, and control groups, respectively; there were significant differences between initial extract group and control group, and between initial extract group and secondary group (P lt; 0.05), but there was no significant difference between secondary extract group and control group (P gt; 0.05). However, no significant difference was observed in the ALP activity [(0.013 01 ± 0.000 39), (0.012 93 ± 0.000 44), and (0.012 92 ± 0.000 35) U/ mg], apoptosis rate (7.03% ± 1.95%, 6.46% ± 2.88%, and 6.18% ± 2.21%), horizontal migration [(137.50 ± 11.43), (134.98 ± 10.50), (135.21 ± 8.66) μm], and transmembrane cell number [(10.92 ± 4.99), (10.07 ± 2.50), and (9.81 ± 2.64) cells/ field] among initial extract, secondary extract, and control groups (P gt; 0.05). Conclusion This novel borate bioglass has excellent cytocompatibil ity, which plays regulatory effects on the cell prol iferation, secretion, and migration.
Objective Bioactive borate glass (BG) has good biocompatibil ity and biodegradation. To investigate the feasibilty of bioactive borate glass as a carrier of the antibiotic controlled-releasing by implanting vancomycin-loaded BG (VBG)into the focus of tibia chronic osteomyel itis after debridement. Methods VBG and vancomycin-loaded calcium sulfate (VCS) were prepared with a vancomycin content of 80 mg/g. Sixty-five New Zealand white rabbits, weighing 2.12-3.91 kg (mean, 2.65 kg), were used. The tibia chronic osteomyel itis rabbit models were establ ished by injecting methicill in-resistant Staphylococcus aureus (MRSA, 0.1 mL, 1 × 109 cfu/mL) into the right tibia of 65 rabbits. After 3 weeks of injection, 54 rabbits of successful models were randomly divided into groups A (n=11), B (n=11), C (n=16), and D (n=16). Simple debridement was performed in group A; BG, VCS, and VBG were implanted into the infection sites of groups B, C, and D respectively after thorough debridement. A sample of the debrided tissues was harvested for bacterial examination. The vancomycin serum levels were determined in groups C and D at 1, 2, 4, 10, 24, and 48 hours after operation. The boron serum levels were determined in groups B and D at 10, 24, 48, 72, and 120 hours after operation. After 8 weeks, the effectiveness was assessed radiographically, bacteriologically, and histopathol ogically. Results Ten rabbits died after operation. No vancomycin was detected in group C; the vancomycin level increased gradually, reached the highest level at 4 hours after operation, and then decreased rapidly in group D. No boron was detected in group B; the boron reached the highest serum level at 10 hours after operation, and then decreased gradually in group D. At 8 weeks, calcium sulfate degraded in group C; BG degraded partially in group D; and no obvious degradation was observedin group B. The repair effect was better in group D than in group C. There was no significant difference in radiograph scoring between groups A, B, C and D (P gt; 0.05) before operation, but there was significant difference between group D and groups A, B, C (P lt; 0.05) at 8 weeks after operation. The bacterial culture showed that all the MRSA results were positive in 4 groups. At 8 weeks, the negative rates of MRSA examination were 36.36%, 18.18%, 73.33%, and 81.25% respectively in groups A, B, C, and D, showing significant differences between group D and groups A, B (P lt; 0.05). The histopathological observation showed that a large number of new bones formed and no foreign body reaction occurred in group D. The histopathologic scores of groups A, B, C, and D were 6.45 ± 3.62, 7.55 ± 3.36, 4.27 ± 2.91, and 3.81 ± 3.04 respectively, showing significant differences between group D and groups A, B, and between group C and group B (P lt; 0.05). Conclusion VBG can improve the repair of bone defect in the treatment of chronic osteomyel itis.