Acute Toxic Responses of the Rockfish (Sebastes schlegeli) to Iranian Heavy Crude Oil

Abstract

This study examines whether acute toxic responses played by theinnate immune system depend on which metabolic pathway wasinduced after exposure to crude oil. We exposed juvenile rockfishto spilled crude oil (Iranian Heavy Crude Oil IHCO in gelatincapsules) from the “Hebei spirit” oil spill by feeding. The effects onmultiple fish hepatodetoxification enzymes (Cytochrome P4501Aand GST) and the expression level of the immune response genes,including interleukin-1beta (IL-1β), granulocyte colony-stimulatingfactor (G-CSF) and Cathepsin L (CTSL), were measured in the liver,spleen and kidney. The oil-fed fish had significantly higher concentrationsof biliary fluorescent metabolites and CYP1A expressionduring the initial stage after exposure (12∼48 h after exposure) thanthose in the liver and kidney of the control group. Similarly, thehighest mRNA expression levels of IL-1 β and G-CSF were detectedin the liver at the early stages of exposure (12 h after exposure).Following exposure, the levels of ISG15 and G-CSF mRNA remainedhigh at 120 h after treatment in the liver but the levels of IL-1 βand CTSL gradually decreased to an expression level equal to or lessthan the control group. Our data suggest that the innate immune andhepatodetoxification responses in oil-fed fish were induced at theinitial stage of exposure to the IHCO at the same time but severalimmune-related genes decHCO in gelatincapsules) from the “Hebei spirit” oil spill by feeding. The effects onmultiple fish hepatodetoxification enzymes (Cytochrome P4501Aand GST) and the expression level of the immune response genes,including interleukin-1beta (IL-1β), granulocyte colony-stimulatingfactor (G-CSF) and Cathepsin L (CTSL), were measured in the liver,spleen and kidney. The oil-fed fish had significantly higher concentrationsof biliary fluorescent metabolites and CYP1A expressionduring the initial stage after exposure (12∼48 h after exposure) thanthose in the liver and kidney of the control group. Similarly, thehighest mRNA expression levels of IL-1 β and G-CSF were detectedin the liver at the early stages of exposure (12 h after exposure).Following exposure, the levels of ISG15 and G-CSF mRNA remainedhigh at 120 h after treatment in the liver but the levels of IL-1 βand CTSL gradually decreased to an expression level equal to or lessthan the control group. Our data suggest that the innate immune andhepatodetoxification responses in oil-fed fish were induced at theinitial stage of exposure to the IHCO at the same time but severalimmune-related genes dec