DNA oxidative damage of neoplastic rat liver lesions

Hepatic lesions, experimentally-induced in Fisher 344 (F344) and Brown Norway (BN) rats, respectively, susceptible and resistant to liver carcinogenesis, progress differently to hepatocellular carcinoma (HCC). The mechanisms responsible for the acquisition of the resistant phenotype are not completely clear. Herein, we show that in F344 rats subjected to carcinogenic treatment, angiogenesis and DNA oxidation markers increase in preneoplastic and neoplastic liver lesions. On the contrary, in the HCCs of treated BN rats, angiogenesis and a minor DNA oxidation are accompanied by an attempt of tissue remodelling. This study suggests that DNA oxidation might be an important factor in the initiation and promotion of the events of hepatocarcinogenesis. On the other hand, the enhancement of GSH levels and the down-regulation of superoxide dismutase (SOD) expression in both rat strains suggest that antioxidant response is not involved in the acquisition of resistant phenotype.