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

Abstract 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 μmol/kg) or corn oil (control group). We analyzed expression of the ras oncogene and the Hypoxia-inducible factor-1 alpha (hif-1α) 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 μmol/kg B[a]P, showing 4.96, 7.10 and 6.78-fold increases, respectively. Overexpression also occurred in hif-1α in fish injected with 4 and 8 μmol/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 μmol/kg μM B[a]P. The genotoxic damage increased in fish injected with 8 and 16 μmol/kg in comparison with the control group. Acute exposure of B[a]P was capable to interrupt the expression of ras oncogene and hif-1α, and increase DNA breaks due to tissue damage

Exposure to waterborne copper and high temperature induces the formation of reactive oxygen species and causes mortality in the Amazonian fish Hoplosternum littorale

Hoplosternum littorale is an Amazon fish that lives in urban areas surrounded by polluted igarapés, where elevated copper concentrations eventually occur. The central goal of this study was to evaluate the associated effects of high temperature and copper contamination on survival time and biochemical responses of the Amazonian fish species H.littorale. We exposed fish to two nominal dissolved copper concentrations (50 and 500 µg l−1) and combined temperatures of 28 and 34°C. Our findings showed that the combination of these variables affects the survival time of this species. The activity of the biotransformation enzymes ethoxyresorufin-O-deethylase and glutathione-S-transferase showed no alterations in fish within all treatments. The increase of reactive oxygen species and the decrease in potential total antioxidant capacity promoted the imbalance in the antioxidant system. An induction in superoxide dismutase activity occurred in fish exposed to copper concentrations of 50 and 500 µg l−1 at both temperatures, suggesting liver impairments. Thus, we suggest that H. littorale is sensitive to copper, and this sensitivity is increased further with exposure to high temperatures, particularly in the survival time and reactive oxygen species formation of this fish species. © 2016, Springer International Publishing Switzerland

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

Abstract 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 μmol/kg) or corn oil (control group). We analyzed expression of the ras oncogene and the Hypoxia-inducible factor-1 alpha (hif-1α) 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 μmol/kg B[a]P, showing 4.96, 7.10 and 6.78-fold increases, respectively. Overexpression also occurred in hif-1α in fish injected with 4 and 8 μmol/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 μmol/kg μM B[a]P. The genotoxic damage increased in fish injected with 8 and 16 μmol/kg in comparison with the control group. Acute exposure of B[a]P was capable to interrupt the expression of ras oncogene and hif-1α, and increase DNA breaks due to tissue damage