| Background the plate and screw fixation is usually used for thetreatment of fracture. Because of the expensive cost, no biological activityand high elastic modulus,it is easy to cause stress shielding, bone resorption,influence the fracture healing,and in need of a two operation to take out,increased patient suffering and economic burden. Some patients may alsotake place fracture nonunion, bone defect, need bone graft operation again.Therefore, finding a biological fixation material can fix fracture, shorten thehealing time of the fracture, prevent bone nonunion, and avoid a twooperation to take out is many osteopathic surgeons’ dream.Objective To study the the osteogenic effect of bone marrow stromalcells(BMSCs) transfected with human LIM mineralization protein1(LMP-1)gene in nude mouse muscle and the effect and feasibility ofnano-hydroxyapatite/polyamide66(n-HA/PA66) plate combined with bonemarrow stromal cells(BMSCs) transfected with human LIM mineralizationprotein1(LMP-1) gene for the treatment of canine femoral fracture.Methods Dog bone marrow MSCs was isolated， cultured andexpanded in vitro by combining the techniques of tedensity gradientcentrifugation and adherent culture. Then they were transduced by Ad-LMP-1, morphological and Growth characteristics was observed. nudemice in the induction of osteogenesis in muscle were divided into3groups：Dog BMSCs were transfected by Adv-LMP-1gene (group1),by Adenovirusgene(group2)，and uninfected severed as control groups(group3) Each cellsuspension were injected into the posterior femoral intramuscular of thenude mice. X-ray and histological examination were performed to evaluatethe osteogenesis ability of LMP-1gene. BMSCs was transfected withAdv-hLMP-1，And then combine with n-HA/PA66plate. Adhesion andgrowth condition on n-HA/PA66plate was observed By Invertedmicroscope and scanning electron microscope.The Dog models of femurfractures were established and were divided into four groups: Ad-LMP-1transfection group, non-transfected group, n-HA/PA66alone group andplate and screw groups of12samples. X-ray was performed at4th,6th,8th,10th and12th week after surgery to evaluate bone union and Fixationfailure. The gross observation and histological changes were observed at12weeks after operation.Results1.Dog bone marrow MSCs was succdssfully isolated.itsmorphological and growth characteristics were not significantly change afteradenovirus transfection.2. At the4rd and8th week after cellsinjection．ectopic bones were observed in muscles of nude mice of group1,only fibrous tissue or Iittle bone was found in other two groups.3. n-HA/PA66plate has good biocompatibility, Adv-LMP-1transfected BMSCs can grow well on it.4. the failure rate in transfection group are all lower than thatin untransfected group and n-HA/PA66plate group at8or12weekspostoperatively,(P<0.05) And without statistics difference compared withplate and screw group.(P>0.05)the healing time of the transfection group isshorter than the other three group. material plate completely fused withcanine femoral lateral cortex materials after12weeks of operation,and therewas obvious bone formation between material and bone. material plate andcanine lateral femoral cortex only partially fused in untransfected group andn-HA/PA66plate group, and there was no or a small amount of bone tissueformation between material and bone.Conclusion1. LMP-1may induce BMSCs os teoblastic differentiation,so as to promote the formation of bone tissue.2. The treatment of caninefemoral fracture with n-HA/PA66plate combined with BMSCs transfectedwith LMP-1gene can get good fixation effect, promote the fracture healingand fusion with autogenous bone, without the need for a two operation totake out, but the strength of materials have some limitations, for caninefemur treatment of the fracture must be combined with external fixation. |
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