| At present, has turned to the hot topics in the study of fracture healing for the wound to create a good environment and the effective control of infection, biology is this bone surgery is an urgent need to solve the problem, is also the key to a successful treatment of fractures. BMP can induce undifferentiated mesenchymal cells differentiation between cartilage and new bone formation, on bone mass and bone and reconstruction of multidirectional adjustment effect; b FGF can significantly promote cell mitosis and blood vessel formation, accelerate the maturity of cartilage and ossification, can begin in the BMP bone reconstruction after bone repair together; Several main pathogenic bacteria in bone trauma, infection of tobramycin low resistance, high sensitivity; And tobramycin no inhibition effect on BMP to promote bone healing, but can promote fracture repair. FG as a kind of low antigenicity of biological macromolecular materials, accord with BMP and b FGF carrier ideal condition, therefore, this study will be fibrin glue as a scaffold and antibiotic drug control-released carrier, compound can play an important role in the process of bone rebuilding two factors of rh BMP-2 and b FGF and tobramycin, with antibiotics were as a slow-release carrier systems and cytokine role compounds, to evaluate the effects of the compound of fracture healing, and discussed from the Angle of pathologic histology and molecular biology of the complex mechanism in the process of fracture healing, provides the experimental basis for the bone tissue engineering and theoretical basis.This experiment selected 12 dog as experimental animals, under aseptic conditions with orthopaedic pendulum saw standard dog tibia fracture model is established. Every dog with right hind legs for experiment, the left hind leg for comparison. Experimental limb the conventional internal fixation methods + FG/rh BMP-2/b FGF/tobramycin complex fracture reduction fixation, contrast limb only the conventional internal fixation methods for fracture reduction fixation. At 4, 8, 12, 16 weeks postoperatively randomly selected from three samples from fracture organization, preparation of paraffin section, HE staining and MASSON, three color staining with toluidine blue staining to observe the histological changes of fracture and using immunohistochemical method to detect the expression of the four factors in situation, the results are as follows:1. the histological changes: The experimental fracture healing early osteoblasts, cartilage cells of vascular endothelial cells and the proliferation, differentiation, inflammatory clearance period is short, a control group of collagen and bone matrix deposition capacity is much, the trabecular bone formation and fast renovation, advance into the callus reconstruction period, show that FG/rh BMP-2/ b FGF/tobramycin compounds in bone repair period can enhance cell, proliferation, adhesion, create good cell microenvironment for fracture healing, can increase the interaction between cells and cytokines, promote tissue growth, improve the quality of bone repair and reconstruction.2. the expression of VEGF positive rate: the experimental group and control group in VEGF positive rate were reduced after rising first, highest 8 weeks, the experimental group 8 weeks and 12 weeks of significant difference(P < 0.01), the rest of the time difference was not significant; Significant difference were observed in the control group 4, 8, 12 weeks(P < 0.01), 4 and 8 weeks after surgery, the experimental group VEGF positive rate was significantly higher than that of control group(P < 0.01), no significant differences between 12 and 16 weeks. Show that FG/rh BMP-2/b FGF/tobramycin compound in the early fracture healing promotes endothelial cell migration, proliferation, capillaries, improve the local cell metabolism, optimize the local cell microenvironment.3. the expression of PDGF positive rate: postoperative each point in time, the experimental group and control group PDGF are in decline after growth first, the positive rate of experimental group top 8 weeks, the differences between adjacent time point were significantly(P < 0.01); The highest control group 12 weeks, 4 weeks and 8 weeks, 12 and 16 weeks compared with significant difference, the other no significant difference between adjacent time point(P < 0.01). 4 and 8 weeks after experimental PDGF positive rate were significantly higher than that of control group(P < 0.01), 12 weeks, no significant differences between the two groups, 16 w in the control group were higher than that of the experimental group, no significant differences between the two groups. Show that FG/rh BMP-2/b FGF/tobramycin compounds improve alkaline fibroblast proliferation and differentiation, can enhance the osteoblast and fibroblast ahead secretion capacity, promote collagen formation and deposition. Accelerate fracture healing.4. the expression of IGF and TGF- beta 1 positive rate: IGF, TGF- beta 1 are in decline after growth first, the positive rate for 12 weeks, the highest IGF group positive rate between different time points were significantly difference(P < 0.01), the control group differences in 4 weeks, 8 weeks and 12 weeks were significantly(P < 0.01), the experimental group compared with control group, the differences in 4 weeks, 8 weeks and 12 weeks were significantly(P < 0.01); TGF- beta experimental positive rate between different time points were significantly difference(P < 0.01) and control group in 4 weeks, 8 weeks and 12 weeks were significantly difference(P < 0.01), the experimental group compared with control group, the differences in 4 weeks, 8 weeks and 12 weeks were significantly(P < 0.01). Show that FG/rh BMP-2/b FGF/tobramycin can promote osteoblast proliferation differentiation in the form of autocrine and increased collagen synthesis. Stimulate the cells to raise and proliferation, start the repair process. To accelerate bone matrix calcification and rebuilding the trabecular bone at the same time, speed up the healing process.Conclusion: FG/rh BMP-2/b FGF/tobramycin compound in the early fracture of cells and cytokines to create a good environment, promote a variety of cell chemotaxis, adhesion, proliferation and differentiation, the formation of vessels in the fracture end and compact, maintain drug and relatively high concentrations of cytokines, increased bone repair effect, can coordinate the fracture healing reconstruction phase of osteoblast and osteoclast interaction, to accelerate the process of bone rebuilding. |
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