Objective In oder to treat periodontitis by using tissue engineering and gene engineering technology, he article established an transient expression system of bone marrow stromal cells（BMSC） modified by osteoprotegerin OPG） gene and detected its expression using eukaryotic secreted expression pSecTag2/B-OPG plasmid. Methods y solation and culture of BMSC in vitro, the identified recombined plasmid was transiently transfected into BMSC y Lipofectamine 2000 and OPG expression in BMSC was determined by RT-PCR and Western blot in 6 weeks. esults The fragments of the recombinant plasmid digested with Hind Ⅲ，EcoR I and BamHⅠ and examined by 0 g/L agarose electrophoresis, were consistent with predicted size. The sequence of OPG was identical to the equence provided by GeneBank [gi：33878056]. OPG transcribing in BMSC was confirmed by RT -PCR and OPG ustainable expressing in BMSC was detected by Western blot in 39 days. Conclusion The transiently expression ystem of BMSC modified by OPG gene was successfully established.
