Objective:To observe the effect of triplex forming oligonucleotide(TFO) of PDGF-B chain on cell proliferation and cell cycle of rat glioma.Methods:1?10 6 C 6 glioma cells with high-flow microinfusion were seeded into right caudate putamen of rats.TFO was used in situ a week after glioma cell inoculation.The treatment groupⅠandⅡwere treated with 1.5 mg/20 ?l and 3.0 mg/20 ?l TFO respectively on 8,11 and 14 d after cell inoculation.The control group was treated with 20 ?l normal saline with the same procedure.Three weeks after cell inoculation all rats were killed and samples were detected with macroscopic,microscopic histology and immunofluorescence flow cytometric analysis.Results:The inhibition rates of tumor growth were 66.1% in the treatment groupⅠand 91.8% in the treatment group Ⅱ.TFO specifically blocked expressions of PDGF-B and PCNA of glioma cells in a concentration-dependent fashion. TFO obviously inhibited the transit of cells from the G 0-G 1 to S phase in a concentration-dependent fashion.Conclusion:TFO can commendably block PDGF-B expression,inhibit cell proliferation and induce C 6 glioma cells arrest in the G 1 phase,and thus inhibit tumor growth of glioma.