The Application Of Adipose Tissue With Pedicle Compounding RhBMP-2 To Rabbit Spine Fusion

The application of adipose tissue with pedicle compounding rhBMP-2 to rabbit spine fusionObjectiveSpinal fusion is one of the most common ways to treat spinal diseases. Transverse process fusion is the frequently used spinal fusion method. Currently, autologous bone or allogenic bone is usually used to spinal fusion for most clinical situations. However, autologous bone can't provide enough bone to spinal fusion and has a number of major disadvantages: more hemorrhage when operating; postoperative pain at donor site; the ability to fabricate a functional shape is limited et al. Allogenic bone transplantation has disadvantages such as immune response and diseases transmitted et al.Fibrin Glue (FG) is the appropriate carrier of Bone Morphogenetic Protein (BMP) in our experiment. The adipose tissue with pedicle skin flap compounding rhBMP-2 makes the rabbit spine fusing between the transverse process. Radiographic analysis,biomechanical test and histologic examination are used to check spinal fusion condition. We hope our study can provide more efficient method for spinal fusion.Methods1.The source of animals40 one-year-old (weight 3-5 Kg) healthy Japanese rabbits (no female or male limited), which are provided and raised by China Medical University.2. Preparing FG and FG compounding rhBMP-2Prepare solutionâ… :one bottle of FG dissolved in 10 ml distilled water. Prepare solutionâ…¡: thrombin dissolved in 2 ml CaCl₂ solution. Then we adjusted the PH of solutionâ… and solutionâ…¡to 7.0—7.2.3. Animal models construction40 one-year-old rabbits are equally divided into 2 groups randomly: the pure adipose group and the adipose tissue compounding rhBMP-2 group. Spinal fusion operation is taken, burnishing the cortex, revealing the marrow cavity of transverse process, putting the carrier to the L₅—L₆ transverse process. All the animals are sacrificed 8 weeks after operation and take the spine specimens out. To the specimens, the examination is carried out including: (1) observing by eyes; (2)radiographic observation; (3)gray analysis; (4)biomechanical test; (5)histologic examination.ResultsWe can see connective mass exist between the left L₅,L₆ transverse processes of the specimens in the adipose tissue compounding rhBMP-2 group. At 8th week, the fusion ratio of the adipose tissue compounding rhBMP-2 group is 50% and at 6th week is 33%. There is nothing between the left L₅,L₆ transverse processes of all the specimens in the pure adipose group. CT scan and 3D-CT show there is continous bone mass between L₅,L₆ transverse processes.Gray analysis shows bone density and area of the specimens in the adipose tissue compounding rhBMP-2 group at 8th week is significantly higher than at 6th week.Biomechanical test shows fusion strength of the specimens in the adipose tissue compounding rhBMP-2 group at 8th week is significantly higher than at 6th week.HE dyeing shows there are mature bone tissues in bone mass between transverse processes of the fusion specimens in the adipose tissue compounding rhBMP-2 group at 8th week and at 6th week.Masson dyeing shows collagen tissues are abundant in the trabecula of the specimens in the adipose tissue compounding rhBMP-2 group.DiscussionFG can become appropriate carrier because many advantages, such as good plasticity, adjustable clotting time, deliverying a lot kinds of factors which can promote BMP to adhere and generate, suitable degradation speed, etc.Tissue engineering bone includes three essential elements: (1) ideal seed cell, (2) appropriate carrier, (3) osteogenic inducter.Vitamin C,β- sodium glycerophosphate, Dexamethasone, BMP can promote osteogenic differentiation. Stronger adhesive power of FG is favorable for the slow delivery of BMP, and the macromolecule proteinum character of FG can avoid BMP non-specificity proteolysis.Biomechanical test shows fusion strength of the specimens in the adipose tissue compounding rhBMP-2 group at 8th week is significantly higher than at 6th week. HE dyeing shows there are mature bone tissues in bone mass between transverse processes of the fusion specimens in the adipose tissue compotmding rhBMP-2 group at 8th week and at 6th week. These all proved that the adipose tissue compounding rhBMP-2 could be the very well spine fusion material.ConclusionThe adipose tissue compounding rhBMP-2 could be the very well spine fusion material.