In order to study whether the endothelial cells (ECs) with lipid peroxidation induced by diamide can express and secrete macrophage inflammatory protein 1α (MIP-1α), the expression of MIP-1α protein in the cells was detected by cell enzyme-linked immunosorbent assay (ELISA) and that of MIP-1α mRNA was determined by cell in situ hybridization and nuclease S1 protection assay after the ECs were exposed to different concentrations of diamide for 4 h. The chemotactic activity of MIP-1α was tested by micropore filter method using modified Boyden chambers. Cell ELISA showed that the expression of MIP-1α protein in endothelial cells exposed to 1 μmol/L, 5 μmol/L and 10 μmol/L diamide was 1.9-fold, 2.3-fold and 1.7-fold respectively as much as that in the control cells, which was statistically significant by analysis of variance. In situ hybridization revealed that the mRNA expression of ECs treated with 1 μmol/L, 5 μmol/L and 10 μmol/L diamide was 1 3-fold, 3.0-fold and 1.7-fold as much as that in the control group, which had statistical significance ( F =188.93, P <0.01). The mRNA expression in 5 μmol/L dimide treated ECs, measured by nuclease S1 protection assay, was 3.4-fold as much as that in the control group( t =8 70, P <0 05). Chemotactic response(99.50±4.31 μm) to the culture medium conditioned by 5 μmol/L diamide treated ECs , which was stronger than that(66.47±3.25 μm) conditioned by the ECs ( F =404.31, P <0.05), was significantly decreased ( F =192.25, P <0.05) after adding MIP-1α antibody. It suggests that diamide, a lipid peroxidation inducer, could stimulate ECs to produce high level of MIP-1α, and might play an important role in atherogenesis by promoting the migration of peripheral blood monocytes into arterial intima. In order to study whether the endothelial cells (ECs) with lipid peroxidation induced by diamide can express and secrete macrophage inflammatory protein 1α (MIP-1α), the expression of MIP-1α protein in the cells was detected by cell enzyme-linked immunosorbent assay (ELISA) and that of MIP-1α mRNA was determined by cell in situ hybridization and nuclease S1 protection assay after the ECs were exposed to different concentrations of diamide for 4 h. The chemotactic activity of MIP-1α was tested by micropore filter method using modified Boyden chambers. Cell ELISA showed that the expression of MIP-1α protein in endothelial cells exposed to 1 μmol / L, 5 μmol / L and 10 μmol / L diamide was 1.9-fold, 2.3-fold and 1.7-fold respectively as much as that in the control cells, which was significantly significant by analysis of variance. In situ hybridization revealed that the mRNA expression of ECs treated with 1 μmol / L, 5 μmol / L and 10 μmol / L diamide was 1 3-fold, 3.0 -fold and 1.7-fold as much as that in the control group, which had statistical significance (F = 188.93, P <0.01). The mRNA expression in 5 μmol / L dimide treated ECs, measured by nuclease S1 protection assay, was 3.4- fold as much as that in the control group (t = 8 70, P <0 05). Chemotactic response (99.50 ± 4.31 μm) to the culture medium conditioned by 5 μmol / L diamide treated ECs, which was stronger than that (66.47 ± 3.25 μm) by suggests that the diamide, a lipid peroxidation inducer, could stimulate ECs to produce high level of MIP-1α, and might play an important role in atherogenesis by urged the migration of peripheral blood monocytes into arterial intima.