Ras oncogene and Hypoxia-inducible factor-1 alpha (hif-1α) expression in the Amazon fish Colossoma macropomum (Cuvier, 1818) exposed to benzo[a] pyrene

Benzo[a] pyrene (B[a] P) is a petroleum derivative capable of inducing cancer in human and animals. In this work, under laboratory conditions, we analyzed the responses of Colossoma macropomum to B[a] P acute exposure through intraperitoneal injection of four different B[a] P concentrations (4, 8, 16 and 32 mu mol/kg) or corn oil (control group). We analyzed expression of the ras oncogene and the Hypoxia-inducible factor-1 alpha (hif-1 alpha) gene using quantitative real-time PCR. Additionally, liver histopathological changes and genotoxic effects were evaluated through the comet assay. Ras oncogene was overexpressed in fish exposed to 4, 8 of 16 mu mol/kg B[a] P, showing 4.96, 7.10 and 6.78-fold increases, respectively. Overexpression also occurred in hif-1 alpha in fish injected with 4 and 8 mu mol/kg B[a] P, showing 8.82 and 4.64-fold increases, respectively. Histopathological damage in fish liver was classified as irreparable in fish exposed to 8, 16 and 32 mu mol/kg mu M B[a] P. The genotoxic damage increased in fish injected with 8 and 16 mu mol/kg in comparison with the control group. Acute exposure of B[a] P was capable to interrupt the expression of ras oncogene and hif-1 alpha, and increase DNA breaks due to tissue damage.