Experimental studies have demonstrated that
oral administration of
lanthanum chloride (LaCl(3)) inhibits the development of
atherosclerosis, but the related mechanism has not been fully elucidated.
Oxysterols are toxic to the vascular endothelial cells which are important in preventing the formation and progression of
atheromatous plaque. In this study, we examined the effect of LaCl(3) on
oxysterol cholestane-3β,5α,6β-triol (Triol)-induced apoptosis and the related mechanisms in ECV-304 cells, a presumptive endothelial cell line. Incubation with Triol resulted in apoptosis of ECV-304 cells, as determined by
Hoechst 33342 staining,
fluorescein isothiocyanate labeled
annexin V/
propidium iodide double staining, and the loss of mitochondrial membrane potential. Triol activated
extracellular-signal-regulated kinase (ERK) and nuclear factor κB (NF-κB), and inhibition of Triol-activated ERK and NF-κB signaling by specific inhibitors attenuated apoptosis induction by Triol in ECV-304 cells. Pretreatment with LaCl(3) (1 μM) for 12 h before exposure to Triol decreased Triol-mediated apoptosis as well as activation of ERK and NF-κB. In addition, Triol induced oxidative stress in ECV-304 cells, manifested by the increase of intracellular
reactive oxygen species generation and
malondialdehyde level, and the reduction of the content of total
protein thiols and the activity of
antioxidant glutathione peroxidases; LaCl(3) pretreatment significantly reversed these effects. Finally, LaCl(3) pretreatment significantly inhibited the increases of intracellular Ca(2+) concentration induced by Triol. Our study suggests that Triol induced ECV-304 cell apoptosis, and LaCl(3) could suppress this effect probably by inhibiting intracellular Ca(2+) concentration elevation, oxidative stress, as well as activation of ERK and NF-κB signaling pathways.