Objective To overview the effect of bacterial biofilms (BBF) on the formation of chronic osteomyel itis and the treatment measure. Methods The original articles in recent years about the relationship between BBF and chronic osteomyel itis were reviewed. Results The diagnosis and treatment of chronic osteomyel itis was very difficult, besides hyperplasia oflocal scar, poor blood supply, drug-resistant, forming of BBF also was an important reason. BBF formed on the surface of necrosis soft tissue and dead bone. Due to the protection of BBF, the bacterium were far more resistant to antimicrobial agents, which caused the recurrence of chronic osteomyel itis. The forming of BBF included three processes which were adhesion, development and maturity. As the major pathogens of chronic osteomyel itis, staphylococcus had its own characteristic. Designing therapeutic programmes according to these characteristics had become the trend of anti-infection treatment of BBF. Conclusion Although there are lots of studies on anti-biofilm due to the key factors during the forming of BBF, the most effective way of anti-biofilm is still debridement.
ObjectiveTo review the advances in the computational fluid dynamics (CFD) in tissue engineering.MethodsThe latest research of CFD applied to tissue engineering were extensively retrieved and analyzed, the optimization of bioreactor design and the simulation of fluid dynamics and cell growth kinetics during tissue regeneration in vitro were mainly reviewed.ResultsThe simulation and predictive capabilities of CFD can provide important guidance for the optimization of bioreactor design, and the cultivation of engineering tissue. The accuracy of model prediction results can be further improved by combining with experimental research.ConclusionAs a new and effective research tool, CFD has its unique advantages in the application of tissue engineering. However, a more comprehensive and accurate simulation of the whole process of tissue regeneration still needs further studies.
【Abstract】 Objective To investigate the anti-infection and bone repair effects of cationic l i posome-encapsulatedvancomycin combined with the nano-hydroxyapatite/chitosan/konjac glucomannan (n-HA/CS/KGM) composite scaffold invivo. Methods Fifty-one 6-month-old New Zealand white rabbits, weighing 1.5-3.0 kg, were selected to prepare chronicinfectious 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 l i posome-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 swell ing. 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 pathologieal scores of group D were significantly better than those of groups A and B (P lt; 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 lt; 0.05). New bone formation was observed in groups C and D, but periosteal reactionand 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 lt; 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 lt; 0.05). Bacteriological results showed higher negative rate in groups C and D than in groups A and B (P lt; 0.05). Conclusion Cationic l iposome-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.
Objective To evaluate the tissue response induced by three kinds of bone transplantation materials implanted in rat so as to provide proper evidence for their cl inical appl ication. Methods Thirty-six healthy mature Sprague- Dawly mice, weighing from 229 g to 358 g, were randomly assigned to groups A and B (n=18). Three kinds of materials wereimplanted into muscles of rats. Calcium sulfate (CS) granular preparations and allogeneic demineral ized bone matrix (DBM) were transplanted into the left (group A1) and right (group A2) thigh muscle pouches of group A. Respectively, whereas xenogenic DBM were transplanted into the left (group B1) thigh muscle pouches of group B and the right (group B2) sites were taken as control without implant. The samples (n=6) were collected to make the observation of gross and histology and to analyze histological score after 2, 4, and 6 weeks. Results The gross observation: implanted materials were gradually absorbed at late stage in group A1. No obvious degradation and absorption, but fibrosis of tissues were observed in group A2 and B1. The inflammatory reactions were more severe in groups A2 and B1. In group B2, only the changes of scar were seen at operative site. The histological observation: no obvious inflammatory reactions were seen in group A1, CS were gradually absorbed and completely absorbed at 6 weeks, while fibrosis of tissues increased at late stage. Inflammatory reactions in group A2 and group B1 were alleviated gradually, no obvious absorption and degradation were observed. The different two DBM could induce granulation tissues and bone formation at different sites and secondary fibrosis with no obvious immune response was observed. In group B2, there was an increase in collagen fiber density and angiogenesis at late stage. The scores of inflammatory infiltration were significantly higher in groups A2, B1 than in groups A1, B2 (P lt; 0.05), and the scores of fibrosis was larger in groups A1, A2 and B1 than in group B2 (P lt; 0.05). Conclusion CS has rapid dissolution and good biocompatibil ity. It is a good replaceable packing materials of bone defects in some upper l imb’s or acute bone fracture. Both of two DBM have biocompatibil ity and osteoinductive potential, which dissolution are very slow. Due to these capacity, they can be served as an ideal materials in treatment of lower l imb’s bone defect and nonunion.
Objective It is difficult to treat chronic osteomyel itis due to the formation of the Staphylococcus aureus biofilms. Liposomal gentamicin-impregnated allogeneic cortical bone can inhibit the formation of the Staphylococcus aureusbiofilms. To explore the treatment of chronic osteomyel itis of rabbit by l iposomal gentamicin-impregnated allogeneic cortical bone. Methods The l iposomal gentamicin, l iposomal gentamicin-impregnated allogeneic cortical bone and gentamicinimpregnated allogeneic cortical bone were produced. Then the chronic Staphylococcus aureus osteomyel itis models of rabbit were made in left lower l imbs of 40 6-month-old rabbits and the right lower l imbs were used as controls. After 2 weeks, the observations of gross and X-ray were done. Four rabbits died within 10 days after the models were made and other 36 rabbits were devided into 6 groups: group A (no antibiotics), group B (intravenous injection of gentamicin), group C (intravenous injection of l i posomal gentamicin), group D (implantation of gentamicin-impregnated allogeneic cortical bone), group E (implantation of l i posomal gentamicin-impregnated allogeneic cortical bone), and group F (implantation of allogeneic cortical bone). After 2 weeks of treatment, the bacterial culture, X-ray and HE staining were done. Results The chronic Staphylococcus aureus osteomyel itis model of rabbit was made successfully. The X-ray showed dissolution of bone and periosteal reaction in groups A, B, C, and F, and no obvious dissolution of bone and periosteal reaction in groups D and E. The Norden scores were (2.5 ± 0.3), (2.1 ± 0.2), (1.5 ± 0.3), (1.5 ± 0.2), (0.9 ± 0.3), and (2.7 ± 0.3) points in groups A-F, respectively; showing significant differences between group A and groups B-E (P lt; 0.05), between groups B, E, F and other groups (P lt; 0.05). The results of blood and marrow cultures for Staphylococcus aureus were positive in groups A and F, and negative in other 4 groups; the results of bone marrow culture for Staphylococcus aureus were positive in 6 rabbits of group B, 4 rabbits of group C and 3 rabitts of group D; and the results were negative in group E. HE staining showed: in groups A and F, abscess and dead bone formed, and no new bone formation were observed; in groups B and C, different degrees of neutrophil accumulation was seen; in group D, some neutrophil accumulation occurred, and osteoprogenitor cells and osteoclasts were seen around implanted bone; and in group E, no neutrophil accumulation was observed, a lot of granulation tissues formed, and osteoprogenitor cells and osteoclasts were seen around implanted bone. Conclusion Implantation of l iposomal gentamicin-impregnated allogeneic cortical bone has remarkly better effect in treating chronic osteomyel itis than intravenous injection of l iposomal gentamicin and implantation of gentamicin-impregnated allogeneic cortical bone.