Abstract: A study on the effect s of 17β- est radiol against the expression of interleukin - 6 ( IL -6) and tumor necrosis factor ( TNF) induced by low - density lipoproteins(LDL) on vascular endothelial cells (VECs) was carried out . The level of IL - 6 and TNF were measured in cultured human umbilical vein endothelial cells. LDL significantly raise the level of IL - 6 and TNF in cultured endothelial cells. In LDL 100μg/ ml , TNF activity was 0. 74 ±0. 09 (ng/ ml) and IL - 6 activity was 91. 64 ±7. 39 (u/ ml) . 17β- est radiol can significantly decrease the expression of IL - 6 and TNF induced by LDL in cultured endothelial cells. However , when tamoxifen and 17β-est radiol were added at the same time , the level of IL - 6 and TNF significantly increased compared with that in the cont rol group ( P < 0. 05) . These indicate that the protection of 17β-est radiol on VECs may be through est rogen receptor partially.

Key words: endothelial cells, est rogen, low - density lipoproteins, interleukin - 6, tumor necrosis factor