| Objective:Distraction osteogenesis (DO) adopted in clinical applications for several decades has been used to treat leg length discrepancy caused by various disease such as traumatic bone defect, epiphyseal injury, and bone defect caused by bone tumors and bone infection, short limb deformity caused by polio heritage, and Congenital short limb deformities and limb hypertrophy and so on.Distraction osteogenesis gains great popularity in clinical applications for its unique way of osteogenesis and incomparable clinical efficacy Compared with other techniques. In recent years, with the constantly improving of distractor and the continuous improvement of the operation design, the technology has been developing by leaps and bounds, the scope also more and more widely in clinical application.But clinical application is more mainly in tibia, many of literatures have been reported. Mainly because the tibic lengthening is relatively simple, but in some specific cases the femoral lengthening must be used to patient, femoral lengthening cases has been reported in literature, the treatment effect is satisfactory, but the treatment process also exists shortage, such as long duration and poor bone formation, etc.In our study, the rabbit model of bone defect was treated by distraction osteogenesis with a novel distractor invented by us. Total flavonoids from rhizoma drynariae was used during the process of DO, in order to achieve accelerated the new bone formation, mineralization and model reconstruction of femur bone defects during the process of DO, accelerate the speed of new bone formation and osteogenesis quality, which can shorten the entire treatment cycle, so as to provide femoral distraction osteogenesis an efficient and effective method by promoting the process of osteogenesis.Methods:一、The distractor was designed and made, then, it was applied on the rabbit model of femoral bone defect. The femoral samples of rabbits were taken and assessed by the callus of distracted zone observed by perusal and X ray.二、42new zealand white rabbits was randomly divided into three experimental groups:model group, treatment group (intervened by Total flavonoids from rhizoma drynariae and control group(intervened by rhBMP-2). The osteotomy length was1.4cm in all the experimental animals.14rabbits in each group (N=14),28femoral specimens (N-28). The speed and quality of new formatting bone was observed and assessed by:1. general observation;2. X ray;3.scanning of Micro CT;4. Bone biomechanical testing;5.detecting the expression level of BMP-2mRNA gene by RT-QPCR.5. observing histologic features by light microscopy.7. observation by scanning electron microscope.Results:一. Gross specimen observation of the model of DOOver time, the naked eye can distinguish callus growth from less to more in the area of distraction, and gradually calcification;At7days of consolidation, the new bone have a bright red color in the area of distraction, the normal boundaries of both ends of the bone is very clear, both ends of the callus growth more, the middle has not been grown;at14days of consolidation, the color of the new bone is becoming lighter、 compact, well-proportioned in the area of distraction compared with the previous. Fracture callus was cylindrical through both ends of the fracture, the normal boundaries of both ends of the bone is fuzzy over the previous;At28days of consolidations, the surface of New bone have normal bone color and same texture in the area of distraction, the naked eye is more difficult to distinguish the boundaries between normal bone and new bone, bone mineral density was significantly higher.二、X-ray observation of the model of DOX-ray inspection was instantly taken after operation, the distractor was fixed stably, counterpoint is good to the line.X-ray inspection was taken at the end day of the distraction, cloudy shadows was visible at the Remote of distraction gap; at7days of consolidation, cloudy shadows was deepen and extended;At14days of consolidation, the cloudy shadows connected the two ends of the normal bone, density is further increased; fixed the third week, a marked new bone tissue connected both ends of the normal bone;At28days of consolidation, new bone tissue calcified completely, cortical formed fully, medullary cavity was unimpeded三. General observation of samples after treatmentAt14days of consolidation:three groups of new bone from high to low quality or hardness:the control group>the treatment group>the model group.At28days of consolidationks:The osteogenesis quality high to low:the control group>the treatment group>the model group.四. X-ray observation after treatmentX-ray inspection was instantly taken after operation, the distractor was fixed stably, counterpoint is good to the line.At the end day of distraction, the model group had no significant shadow, the treatment group and the control group had the formation of new bone and osteoid.At7days of consolidation, cloudy shadows was markedly visible at the Remote of distraction gap, cloudy shadows was deepen in the treatment group and throughout both the ends of femur fracture, the cylindrical cloudy shadows was deepen in the control group compared with the previous.The proximal portion of the cortical density increased, partially calcified.At14days of consolidation, cloudy shadow was deepened in the control group, and the emergence of the shadow of the cortical bone, new bone mineral density of the treatment group compared with the control group and the treatment group is lower.At21days of consolidation, the bone mineral density of the new born from low to high as the model group, treatment group and control group.At28days of consolidations, the new bone mineral density of the control group and the treatment group was significantly higher than that in the model group.五. Micro-CT test results after treatmentModel group, treatment group and control group were drawn at14and21days of consolidation and did MICRO-CT quantitative bone scan and image comparison.From Micro-CT scanning images, osteogenesis and bone modeling of the control group was significantly stronger than the model group and the treatment group at14days of consolidation, osteogenesis and bone modeling of the treatment group was slightly better than the control group;At28days of consolidations, osteogenesis and bone modeling of the control group and the treatment group were stronger than the model group, osteogenesis and bone modeling of the control group was slightly better than the treatment group.BMC, TMC, BMD, TMD, Tb. N, Tb. Pf:at14days of consolidation, the control group was statistically significant (P<0.05)with the model group, treatment group was not statistically significant (P>0.05) with model group and the control group. At28days of consolidations, the treatment group and the control group was statistically significant (P<0.05) with model group, the treatment group was not statistically significant (P>0.05)with the control group.BV/TV:the control group was statistically significant (P<0.05)with the model group at14days of consolidation, the treatment group was not statistically significant (P>0.05) with the model group and control group. At28days of consolidations, the control group was statistically significant (P<0.05)with the model group, the treatment group was not statistically significant (P>0.05) with the model group and control groupTb. Sp, Tb. Th, SMI, At14days of consolidation there was not statistically significant (P>0.05)between the groups. At28days of consolidations, the treatment group and the control group was statistically significant (P <0.05)with the model group, the treatment group was not statistically significant (P>0.05)with the control group六. Mechanical testing after treatmentSectional moment of inertia, maximum load, maximum deflection, modulus of elasticity, elastic stress, strain and other indicators, At14days of consolidation the control group was statistically significant (P<0.05) with the model group, the treatment group was not statistically significant (P>0.05) with model group and the control group.At28days of consolidations, the treatment group and the control group was statistically significant (P<0.05) with model group, the treatment group was not statistically significant (P>0.05)with the control groupElastic load and the stiffness elastic strain indicators,at14days of consolidation, the treatment group and the control group was statistically significant (P<0.05)with model group, the treatment group was statistically significant (P<0.05)with the control group. At28days of consolidation, the treatment group and the control group was statistically significant (P<0.05)with the model group, the treatment group was not statistically significant (P>0.05) with the control groupElastic deflection, fixed two weeks, the treatment group was statistically significant (P<0.05)with the model group,the treatment group was not statistically significant (P>0.05)with the model group and control group. At28days of consolidation, the control group was statistically significant (P<0.05)with the model group, the treatment group was not statistically significant (P>0.05)with the model group and control group.Maximum stress, at14days of consolidation there was not statistically significant (P>0.05)between the groups. At28days of consolidation, the treatment group and the control group was statistically significant (P<0.05) with the model group, the treatment group was not statistically significant (P>0.05)with the control group七. RT-QPCR detect purpose genes BMP-2mRNA level after treatmentAt14days of consolidation, the treatment group was not statistically significant (P>0.05) with model group and the control group. At28days of consolidations, the treatment group and the control group was statistically significant (P<0.05) with model group, the treatment group was not statistically significant (P>0.05)with the control group八.Histology by light microscopy observations after treatmentAt14days of consolidation,a large number of osteoblasts in the area of distraction, in the control group there was a small amount of fibrous tissue, new bone trabecular grown extended stretch direction. In the treatment group and model group there was a large number of fibrous tissue, new bone trabecular was less.At28days of consolidation, there was a large number of new bone formation, treatment group and control groups was filled with new trabecular bone filling stretch aligned, densely arranged, scattered distribution of fiber zone; in model group, new bone trabeculae relatively was sparse, and filled with more fibrous tissue.九. Scanning electron microscopy results after treatmentAt14days of consolidation, the control group arrangement of the collagen fiber bundles was visible along the stretch direction, during which can be seen a lot of new osteoid began to form; model group and treatment group saw a large number of collagen fibers aligned along the stretch, newborn bone the quality is less.At28days of consolidation, control group and treatment group had smooth on the surface of the bone, trabecular bone is more dense, more completely calcified, close to the normal bone surface; thin trabecular bone in the model group, the first two groups there was not more mature trabecular bone compared with other group, the collagen fibers was more, bone surface is not smooth calcification incomplete.Conclusion:1. Through animal experiments show that self-designed single-arm distractor have stable structure, convenient to use, cheap, simple operation, high success rate.2. The distractor applied to the rabbit femur distraction osteogenesis, through the rational design of surgical procedures, it is possible to successfully establish rabbit femoral distraction osteogenesis model.3. Application total flavonoids from rhizoma drynariae in distraction osteogenesis can accelerate new bone remodeling and reconstruction, and the medication is convenient, provides a convenient and economical method to shorten the clinical distraction treatment. |
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