Assessing oxidative stress in Steller sea lions (Eumetopias jubatus): Associations with mercury and selenium concentrations

Details

• Journal Title:
  Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology
• Personal Author:
  Lian, Marianne ; Castellini, J. Margaret ; Kuhn, Thomas ; Rea, Lorrie ; Bishop, Louise ; Keogh, Mandy ; Kennedy, Stephanie N. ; Fadely, Brian ; van Wijngaarden, Edwin ; Maniscalco, John M. ; O'Hara, Todd
  More +
• NOAA Program & Office:
  NMFS (National Marine Fisheries Service) ; AFSC (Alaska Fisheries Science Center)
• Description:
  Selenium (Se) bioavailability is required for synthesis and function of essential Se-dependent antioxidants, including the enzyme glutathione peroxidase (GPx). Strong interactions between monomethyl mercury and Se impair the critical antioxidant role of Se. Approximately 20% of Steller sea lion (Eumetopias jubatus, SSL) pups sampled in the western Aleutian Islands, Alaska, had total Hg concentrations (THg) measured in hair and whole blood above thresholds of concern for adverse physiologic effects in pinnipeds. Importantly, low molar ratios of TSe:THg, in some cases < 1 in several tissues (hair, liver, pelt, muscle, spleen, intestine, heart, lungs, brain) were documented for one SSL pup with THg above threshold of concern, which may lead to antioxidant deficiency. Our aim with this study was to evaluate the relationship between circulating THg, MeHg+, TSe and TSe:THg molar ratio status relative to oxidative stress and antioxidants measured during general anesthesia in free-ranging SSL. We captured, anesthetized and sampled newborn SSL pups at rookeries located in the Aleutian Islands or Gulf of Alaska. Biomarkers analyzed for oxidative stress included 4-hydroxynenonal and thiobarbituric acid reactive substances (4-HNE and TBARS, respectively, lipid peroxidation), protein carbonyl content (PCC, protein oxidation), and GPx activity as a key indicator for Se-dependent antioxidant defense levels. We found a negative association between TBARS and TSe, and SSL with low TSe had higher concentrations of 4-HNE than those with intermediate TSe. These results suggest that SSL with lower TSe experience increased lipid peroxidation potentially associated with THg status.
• Keywords:
  • Steller sea lion
  • Mercury
  • Selenium
  • Oxidative stress
  • Glutathione peroxidase
• Source:
  Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology, 235
• DOI:
  https://doi.org/10.1016/j.cbpc.2020.108786
• Document Type:
  Journal Article
• Rights Information:
  CC BY-NC-ND
• Compliance:
  Submitted
• Download URL:
  https://repository.library.noaa.gov/view/noaa/28864/noaa_28864_DS1.pdf
• File Type:
  [PDF - 751.04 KB]
• Collection(s):
  National Marine Fisheries Service (NMFS)
• Main Document Checksum:
  urn:sha256:dd9fe85fd6d6428f4dc7a0ec9f791cc46cace36297730798c44ac7cb48e7fc47