Objective To investigate the activation and its role of bone morphogenetic protein 2 (BMP2)/Smad1/Runt-related transcription factor 2 (Runx2) signal pathway in renal artery of rat models with vascular calcification. Methods Twenty four male SD rats were randomly divided into control group and calcification group. Rat vascular calcification model was constructed by administration of vitamin D3 plus nicotine. Vascular calcification was confirmed by Von Kossa staining and calcium content was detected by calcium assay. Real time-PCR was applied to detect the expression ofBMP2,Smad1,Runx2mRNA, and immunohistochemistry was used to measure the protein levels of BMP2, Smad1, Runx2, α-smooth muscle actin (α-SMA). Results Von Kossa staining showed a large number of black granules deposited in renal artery. Calcium content in calcification group was significantly higher than that in normal group. Compared with the control group, the expressions of BMP2, Smad1 and Runx2 mRNA in renal artery were increased in calcification group. The protein levels of BMP2, Smad1 and Runx2 were higher while the expression of α-SMA was lower in calcification group than those in control group. The correlation analysis was found a positivie correlation between the calcium content andBMP2mRNA（ r=0.655, P r=0.735, PRunx2mRNA ( r =0.734, P
