OBJECTIVETo observe the influence of either alone or combined mixed-tocopherols combined with eicosapentaenoic acid (EPA) and α-Tocopherol use on oxidized LDL (oxLDL) induced 8-hydroxy-2'-deoxyguanosine (8-OHDG) and interleukin-6 (IL-6) secretion by human umbilical vein endothelial cells (HUVECs) and to explore the potential mechanism.

METHODCultured HUVECs in vitro were incubated with oxLDL, oxLDL + α-tocopherol, oxLDL + mixed-tocopherols, oxLDL + EPA, oxLDL + α-tocopherol + EPA, oxLDL + mixed-tocopherols + EPA for 24 hours, respectively. Secretion of 8-OHDG and IL-6 were detected by cell enzyme linked immunosorbent assay (ELISA). The expressions of superoxide dismutase (SOD), protein kinase C-δ (PKC-δ), phosphorylated PKC-δ (p-PKC-δ) were analyzed by Western blot.

RESULTS8-OHDG and IL-6 secretion of HUVECs was significantly increased significantly after incubated with oxLDL for 24 hours which could be significantly attenuated in the presence of tocopherols and EPA (alone or in combination, all P < 0.05) while the strongest inhibition effects were seen with combined use of mixed-tocopherols and EPA. Moreover, combination of mixed-tocopherols and EPA could also significantly increase SOD activity and decrease PKC activity (all P < 0.05). However, the protein expression of SOD and PKC-was similar among groups.

CONCLUSIONCombined mixed-tocopherols + EPA use enhanced the inhibiting effects on the secretion of 8-OHDG and IL-6 in oxLDL stimulated HUVECs which might be linked with increased SOD activity and reduced p-PKC activity.