IRON MAY INDUCE BOTH DNA-SYNTHESIS AND REPAIR IN RAT HEPATOCYTES STIMULATED BY EGF PYRUVATE/

Background/Aims: Hepatocellular carcinoma develops frequently in the c ourse of genetic hemochromatosis, and a role of iron overload in hepat ic carcinogenesis is strongly suggested, Methods: The aim of our study was to investigate the effect of iron exposure on DNA synthesis of ad ult rat hepatocytes maintained in primary culture stimulated or not by EGF/pyruvate and exposed to iron-citrate complex. Results: In EGF/pyr uvate-stimulated cultures, the level of [H-3] methyl thymidine incorpo ration was strongly increased as compared to unstimulated cultures, Th e addition of iron to stimulated cultures increased [H-3] methyl thymi dine incorporation, The mitotic index was also significantly higher at 72 h, However, the number of cells found in the cell layer was not si gnificantly different from iron-citrate free culture, By how cytometry , no difference in cell ploidy was found between iron-treated and untr eated EGF/pyruvate-stimulated cultures, A significant increase in LDH leakage reflecting a toxic effect of iron was found in the cell medium 48 h after cell seeding, In addition, [H-3] methyl thymidine incorpor ation in the presence of hydroxyurea was increased in iron-treated com pared to untreated cultures, Conclusions: Our results show that DNA sy nthesis is increased in the presence of iron in rat hepatocyte culture s stimulated by EGF/pyruvate, and they suggest that DNA synthesis is l ikely to be related both to cell proliferation and to DNA repair, Thes e observations may allow better understanding of the role of iron over load in the development of hepatocellular carcinoma.