PROTECTION AGAINST UVA DAMAGE AND EFFECTS ON NEUTROPHIL-DERIVED REACTIVE OXYGEN SPECIES BY BETA-CAROTENE

Objective: Phagocyte-derived reactive oxygen species (ROS) are involve d in microbicidal activities as well as in tissue damage at sites of i nflammation. Carotnoids play an important function in protecting cells from oxidant damage. We investigated the in vitro and in vivo effect of 13-cis and 9-cis-beta-carotene on human neutrophils. Methods: Neutr ophils from healthy donors in the presence of 0.25 mu mol/L - 1 mu mol /1 beta-carotene and from subjects under beta-carotene supplementation and UVA or UVA/B exposure were stimulated by opsonized zymosan and th e generation of ROS was measured by electron spin resonance spectrosco py. Results: Our in vitro results show different effects of the two is omers on stimulated neutrophils. 9-cis-beta-carotene did not produce a ny change, whereas 13-cis-beta-carotene significantly and concentratio n-dependent inhibited the ROS generation by stimulated neutrophils. Fu rther, in a controlled study, we were able to demonstrate an in vivo p rotective effect of beta-carotene on neutrophils against UVA damage by beta-carotene supplemented subjects. Conclusions: beta-carotene prese rves the capacity of neutrophils to generate ROS under UVA radiation.