Objective To provide reliable seed cells with unlimited passage proliferation and stable biological characteristics for periodontal tissue engineering research through infecting a retrovirus carrying SV40Tag into SD rat dental follicle cells.Methods Retroviral virus vector containing SV40Tag by 293 cells was packaged and infected into SD rat dental follicle cells. Normal dental capsule cells were used as control group. The cell morphology and vitality were observed by inverted microscope, telomerase activity, osteogenic differentiation and proliferation of dental follicle cells were analyzed.Results The SD rat dental follicle cells infected with SV40Tag could be passaged for 60 generations in vitro culture with strong growth activity. The telomerase activity was significantly enhanced compared with the control group（P=0.033）. The expression of alkaline phosphatase, osteocalcin, bone morphogenesis protein-2, Runx2, basic fibroblast growth factor, insulin-like growth factors had no statistical difference compared with control cells（P>0.05）.Conclusion The SD rat dental follicle cells infected with SV40Tag not only have a strong growth activity and infinite passaged capacity, but also have a stable biological roperty as normal dental follicle cells, so it can be regarded as the excellent seed cells in periodontal tissue engineering.
