Related Experiment Videos
Co-exposure to metals modulates CYP1A mRNA inducibility in Atlantic tomcod Microgadus tomcod from two populations
C Sorrentino1, N K Roy, S C Courtenay
1Department of Environmental Medicine, New York University School of Medicine, 57 Old Forge Road, Tuxedo, NY 10987, USA.
Aquatic Toxicology (Amsterdam, Netherlands)
|September 27, 2005
Summary
Industrial pollutants like heavy metals can reduce fish
Area of Science:
- Environmental Toxicology
- Ecotoxicology
- Biomarker Research
Background:
- Urban and industrial sites expose aquatic populations to complex mixtures of chemical contaminants, including aromatic hydrocarbons (AHs) and heavy metals.
- The combined effects of these contaminant mixtures on aquatic organisms remain largely uncharacterized.
- Atlantic tomcod (Microgadus tomcod) in the highly contaminated Hudson River Estuary exhibit resistance to persistent AHs, shown by reduced hepatic cytochrome P4501A (CYP1A) mRNA inducibility.
Purpose of the Study:
- To investigate the impact of acute co-exposure to metals on aryl hydrocarbon receptor (AHR)-mediated gene expression, specifically CYP1A mRNA inducibility.
- To compare the effects of metals on CYP1A inducibility in a resistant tomcod population (Hudson River) versus a sensitive population (Miramichi River).
Main Methods:
- Adult tomcod from the Hudson River and Miramichi River were intraperitoneally injected with benzo[a]pyrene (B[a]P) or PCB77, followed by graded doses of arsenic (As), cadmium (Cd), chromium (Cr), and nickel (Ni).
- Hepatic CYP1A mRNA and protein levels were quantified to assess gene expression and inducibility.
- Time-course analyses were performed to observe the temporal dynamics of metal-induced modulation of CYP1A mRNA.
Main Results:
- Metals did not affect basal CYP1A mRNA levels but significantly reduced CYP1A mRNA inducibility in tomcod from both populations.
- The degree of CYP1A mRNA inducibility inhibition varied among the different metals and between the two fish populations.
- Temporal patterns of metal-modulated CYP1A mRNA induction differed based on the time of sacrifice post-treatment.
Conclusions:
- Co-exposure to multiple metals can significantly impair inducible CYP1A expression, a key biomarker for AHR activation.
- Metals do not appear to affect basal CYP1A expression levels.
- These findings suggest that metals can interfere with AHR-mediated toxicities, with population-specific responses observed.