Photoreactions for total antioxidant status measurement in humans

Type 2 photoreactions are singlet oxygen (O-1(2)) mediated. This singlet oxygen will de activate by reacting with a number of targets and produce ROS and peroxides that will in turn give Reactive Oxygen Species (ROS). In order to verify whether sera had the same capability to do so we provoked a photoreaction using Rose Bengal (RB) added to sera of 53 healthy donors and at the end of light delivery 2' -7' dichlorofluorescin (DCFH) had been added. In order to avoid any optical artefact we analysed the influence of haemolysis on the fluorescent 2' -7' dichlorofluorescin (DCF) induced by oxidising species. Reactivity to singlet oxygen was slightly different between men and women, varied slightly with age and platelet number. It was remarkably stable over a large period of time and thus represents a characteristic of each serum. Studies are in progress to verify whether ROS dependent diseases would impair this reactivity to singlet oxygen.