Abstract: AIM: To investigate the effects of caffeic acid on apoptosis of HUVEC-12 induced by H₂O₂, and to explore the related phaimacological mechanism. METHODS: The (cells were incubated with H₂O₂ (0. 5 mmol/L) and caffeic acid (1, 10, 100 µmol/L). The viability of HUVEC-12 was measured by MIT assay at different concentrations or times. Flow cytomet analysis was uesd to determine the rate of cell apoptosis. AO/EB dyeing was used to detect the morphological changes of cells. Westem blotting was used to detect the NF-kB, P53 or Bcl-2 protein expression. RESULTS: HUVEC-12 was pretreat ed with 1, 10, 100 µmol/L caffeic acid for 30 minutes followed by 0.5 mmol/L H₂O₂, the rate of cell survival reduced in dose-dependent manner. Results of flow cytoment demonstrated that the apoptotic rate of cells decreased from 21. 9 % ± 2. I % to 3. 8 % ± I. I %. Spontaneous apoptosis was significantly increased in the cells incubated with caffeic acid, meanwhile, the NF-kB protein was upregulated, Bcl-2 protein was down-re lated, ai1d P53 protein was up-regulated. CONCLUSION: Caffeic acid could resist the H₂O₂-induced cell apoptosis, with the possible molecular mechanism of regulating the NF-kB, P53 and BCL-2 expression.

Key words: caffeic acid, HUVEC-12, apoptosis, NF–κB