Changes in blood platelets exposed to UV-B radiation

The effects of UV-B radiation (312 nm) on the pig-blood platelet secretory process (platelet activation) and platelet lipid peroxidation have been stu died. The responses of platelets to UV-B radiation are compared with the re sponse of these cells to thrombin, which is a strong platelet agonist. The obtained results show that exposure of blood platelets to UV-B radiation (1 .2 mW/cm(2), 0.072-8.64 J/cm(2)) causes dose-dependent platelet Lipid perox idation (measured as thiobarbituric acid reactive substances, TBARS) and re lease of adenine nucleotides and proteins from irradiated platelets. The do se-dependent release of platelet compounds from irradiated platelet does no t correlate with the activity of platelet lactic dehydrogenase (marker of c ell lysis) in the extracellular medium. It seems that UV-B radiation can pa rtly activate platelets by stimulating the platelet secretory process and m etabolism of arachidonate. (C) 1999 Elsevier Science S.A. All rights reserv ed.