A Study on the Acute Toxicity of Iranian Heavy

Abstract

This study examines whether acute toxic responses played by the innate immune systemdepend on which metabolic pathway was induced after exposure to crude oil. We exposedjuvenile rockfish to spilled crude oil (Iranian Heavy Crude Oil IHCO in gelatin capsules)from the “Hebei spirit” oil spill by feeding. The effects on multiple fish hepatodetoxificationenzymes (Cytochrome P4501A and GST) and the expression level of the immune responsegenes, including interleukin-1beta (IL-1β), granulocyte colony-stimulating factor (G-CSF)and Cathepsin L (CTSL), were measured in the liver, spleen and kidney. The oil-fed fishhad significantly higher concentrations of biliary fluorescent metabolites and CYP1Aexpression during the initial stage after exposure (12~48 h after exposure) than those inthe liver and kidney of the control group. Similarly, the highest mRNA expression levels ofIL-1β and G-CSF were detected in the liver at the early stages of exposure (12 h afterexposure). Following exposure, the levels of ISG15 and G-CSF mRNA remained high at120 h after treatment in the liver but the levels of IL-1β and CTSL gradually decreased toan expression level equal to or less than the control group. Our data suggest that theinnate immune and hepatodetoxification responses in oil-fed fish were induced at the initialstage of exposure to the IHCO at the same time but several immune-related genesdecreased tCO in gelatin capsules)from the “Hebei spirit” oil spill by feeding. The effects on multiple fish hepatodetoxificationenzymes (Cytochrome P4501A and GST) and the expression level of the immune responsegenes, including interleukin-1beta (IL-1β), granulocyte colony-stimulating factor (G-CSF)and Cathepsin L (CTSL), were measured in the liver, spleen and kidney. The oil-fed fishhad significantly higher concentrations of biliary fluorescent metabolites and CYP1Aexpression during the initial stage after exposure (12~48 h after exposure) than those inthe liver and kidney of the control group. Similarly, the highest mRNA expression levels ofIL-1β and G-CSF were detected in the liver at the early stages of exposure (12 h afterexposure). Following exposure, the levels of ISG15 and G-CSF mRNA remained high at120 h after treatment in the liver but the levels of IL-1β and CTSL gradually decreased toan expression level equal to or less than the control group. Our data suggest that theinnate immune and hepatodetoxification responses in oil-fed fish were induced at the initialstage of exposure to the IHCO at the same time but several immune-related genesdecreased t