In vitro studies on the mechanisms involved in chemoprevention using Calluna vulgaris on vascular endothelial cells exposed to UVB.

The study aims to investigate the mechanisms involved in the in vitro effect of UVB on endothelial vascular cells (HUVECs) pretreated with a photochemopreventive agent, the Calluna vulgaris (Cv) extract. Two concentrations of Cv, below the limit of cytotoxicity IC50 (2.5 and 7.5 μg GAE/ml) and two doses of UVB (50 and 100 mJ/cm(2)) were used. Oxidative stress parameters were quantified at 1 h and 24 h after irradiation and apoptosis, DNA damage and the induction/activation of NF-κB were evaluated at 24 h. UVB exposure led to the formation of lipid peroxides in a dose dependent manner (p<0.001), induced apoptosis, increased the γ-H2AX levels and the activation of NF-κB. Pretreatment with 2.5 μg GAE/ml Cv improved the antioxidant defense, protected against DNA lesions and was able to decrease cellular death at low dose of irradiation. 7.5 μg GAE/ml Cv was prooxidant, favored the formation of DNA lesions, amplified the NF-κB activation UVB-induced (p<0.01) and led to high levels of cellular death. Both doses of Cv inhibited caspase-3 activation. The modulatory effect of Cv extract on endothelial cells exposed to UVB depend on the concentration of Cv used. This study provides insides into the mechanisms triggered by UVB and antioxidants on skin endothelial cells.