ObjectiveTo study the effect of inhibitor of differentiation 1 (Id1) gene transfection on bone morphogenetic protein 2 (BMP-2) promoting the expressions of collagen type Ⅱ (COL Ⅱ) and aggrecan (ACAN) in intervertebral cartilage endplate cells (EPCs). MethodsEPCs were harvested from the New Zealand white rabbits, the 2nd generation EPCs were used for experiment. The transfection efficiency of green fluorescent protein blank lentivirus, high expression of Id1 lentivirus, RNA interference (RNAi) Id1 lentivirus transfection in the EPCs were observed by the fluorescence microscopy, real-time fluorescence quantitative PCR, and Western blot. Blank vector, single BMP-2 gene, BMP-2 and Id1 genes were transfected into EPCs, respectively. The cell morphology and the expressions of COL Ⅱ and ACAN in each group were observed. ResultsLentiviral transfection had no significant effect on the cell morphology. The EPCs were effectively transfected by the high expression Id1 lentivirus and RNAi Id1 lentivirus; the expression of Id1 mRNA was also significantly interfered. The expressions of COL Ⅱ and ACAN mRNA and synthesis of COL Ⅱ and ACAN protein were significantly higher in BMP-2 lentivirus and high expression Id1 lentivirus groups than control group (P<0.05). The expression of COL Ⅱ and ACAN protein were down regulated in the cartilage endplate cells when the expression of Id1 gene was decreased (P<0.05). ConclusionUp-regulation of Id1 gene expression can enhance the effects of BMP-2 on the synthesis of COL Ⅱ and ACAN in EPCs.