RESUMO
BACKGROUND:Polyethylene terephthalate (PEA) holds good mechanical properties, but its biocompatibility needs to be improved. OBJECTIVE:To investigate the effect of bioactive glass modified PEA on bone healing. METHODS:In vitro experiment:PEA (control group) and bioactive glass modified PEA (experimental group) were respectively co-cultured with MC3T3-E1 cells. The cell morphology was observed at 3 days of culture, and the cell proliferation and alkaline phosphatase activity were detected at 1, 3 and 5 days of culture. In vivo experiment:24 New Zealand white rabbits were enrolled, modeled into unilateral knee ligament rupture, and then randomly allotted to two groups. Bioactive glass modified PEA and PEA were implanted into experimental and control groups, respectively. Biomechanics and histological changes were compared between groups at 6 and 12 weeks after transplantation. RESULTS AND CONCLUSION:In vitro experiment:the cell density in the experimental group was significantly higher than that in the control group after 3-day culture (P<0.05);the cell proliferation and alkaline phosphatase activity were significantly higher than those in the control group at 3 and 5 days of culture (P<0.05). In vivo experiment:the maximum axial pull-out strength in the experimental group was significantly greater than that in the control group at 6 and 12 weeks after implantation (P<0.05). In the control group, the defect was obvious and there were a large number of inflammatory cells at 6 weeks after implantation;the defect region became fuzzy, abundant inflammatory cells existed and new bone formed on the surface at 12 weeks after implantation. In the experimental group, there were newly formed bones and trabeculae formed on the interface, the scar tissue became less, and the interface width was narrow at 6 weeks after implantation;numerous new tissues were observed, and only a few inflammatory cells observed in the defect region at 12 weeks after implantation. These results indicate that the modified PEA with bioactive glass possesses good biocompatibility and biomechanics, which can promote bone healing.
RESUMO
BACKGROUND: Ligament Advanced Reinforcement Sytstm (LARS) artificial ligament can avoid the interfibrillar friction compared wiht traditional ligaments, which is conductive for autogenous tissue growth. OBJECTIVE: To investigate the biocompatibility of LARS artificial ligament used for cruciate ligament reconstruction and bone healing. METHODS: Twenty goats were randomly divided into two groups: the anterior cruciate ligament insertion at the femur was cut as stump group; the anterior cruciate ligament insertions at the femur and tibia, and all the ligaments and synovial tissues between them were cut as stump resection group. LARS artificial ligament was then implanted into both two groups. At 20 months after implantation, the ligament healing was observed using CT and MRI examinations, the fibrous tissues were observed under scanning electron microscope, and the growth of newborn ligaments was observed by histological staining. RESULTS AND CONCLUSION: CT findings showed that in the stump group, the number of femoral tunnel enlargement was significantly more than that in the stump resection group (P < 0.05), while the number of tibial tunnel enlargement in the stump group was significantly less than that in the stump resection group (P < 0.05). LARS artificial ligament in the femoral and tibial tunnel and free part of the joint presented with hypointensity on T1- and T2-weighted images, which showed no significant difference between two groups. Under the scanning electron microscope there were obvious dense fibrous tissues between LARS artificial ligaments in both two groups; and the autologous fibrous tissues arranged closely and evenly under high magnification. Hematoxylin-eosin staining results showed that in the two groups, the LARS artificial ligaments in the free part of the articular cavity and bone tunnel were surrounded by a large number of autologous tissues in a fusiform arrangement; autologous fibrous tissues and artificial ligament were wrapped well but arranged irregularly; mature fibrous tissues and few capillary infiltration were found in the bone tunnel and free part of the joint cavity, but without necrotic tissues. Masson staining results showed that the inner and outer parts of the LARS in the bone tunnel were wrapped by blue collagen, the red-stained bones located outside the collagen, and no obvious transitional zone appeared. These results showed that the LARS artificial ligament holds good biocompatibility and fibrous tissue induction, which can promote bone healing.