Effect Of Autogenous Bone Marrow Stromal Cells Transfected With Osteoprotegerin Gene On The Periodontal Therapy In Beagle Dog Periodontitis Animal Model

Objective: To observe the repair effect of the periodontal defects by transplantation of PLGA compounded with Bone Marrow Stromal cells modified of osteoprotegerin gene.Methods:⑴Four adult Beagle dogs, whose 24 incisor teeth were selected to study. All the experimental animals were given silk ligature around the cervix of the teeth and were provided with high sugar diet. With the period, the clinical status were obtained from the experimental teeth, at 1, 2, 4 and 8 weeks.⑵Bone marrow were drawled by puncture,cells were isolated by a whole bone marrow adherence. Cultured the BMSCs with PLGA in vitro. The recombined plasmid was transiently transfected into BMSCs by Lipofectamine 2000. Observed the OPG-transfected BMSCs with PLGA by scanning electronic microscope.⑶After periodontitis model was established, examined with flap operation. Bone defects (3.0mm in depth) were shaped. The defects were randomly assigned to one of the treatments: Experimental group(BMSCs transfected with OPG gene were transplanted into periodontal defect); Negative control group(BMSCs were transplanted into periodontal defect); Blank control group(open flap debridenment).⑷The animals were sacrificed at 6 weeks. Clinical observation and X-ray examination at preoperative moment and after operation and histology examination at the sixth week after operation to appraise the effect of canine alveolar bone regeneration by HE dyeing.The height of new bone and cementum and the formation of new connective tissue were analyzed and compared. The results were analyzed by software package. Results:⑴All the experimental teeth demonstrated significantly an experimental periodontitis;⑵SEM scanning showed that the cells can adhere to the PLGA and extend after 48h culture;⑶Observation of experimental sites were made at the sixth week after the periodontal therapy,the cuts at the periodontal defect districts healed well and had no flare and infection;⑷X-ray surveying showed that the height of new bone was significantly greater in the experimental group than in two control groups.⑸And histoligical observation showed that the experimental groups constructed normal periodontal construction and PLGA had vanished. The defect districts were filled with new alveolar bone, and bone trabeculae could be seen. Root resorption was not found in the experimental group. The amount of new alveolar bone was much more greater than these in two blank groups. The volum of fiber tissue was larger in negative control group, its calcification degree was low and was collogen bone architecture basically. The quantities of new formed bone, cementum and connective tissue in experimental group were more than that in two control groups(P<0.01,P<0.01).Conclusion:⑴The bone marrow stromal cells modified by OPG gene can adhere to the PLGA and extend after culture, is a sign of good biocompatibility.⑵OPG gene therapy associated with tissue engineering can improve the periodontal regeneration obviously.⑶The study proved that BMSCs decorated by OPG gene were good seed cells for periodontal tissue engineering. Our research preliminary identified the feasibility of gene therapy associated with tissue engineering to repair the periodontal defects.