Evaluating immunotoxicity of oil sands process-affected waters using the RAW 264.7 macrophage cell line

• Author / Creator

  Woodall, Kendra M.

• Alberta’s wide-ranging oil sands deposits are recovered via oil sands processes such as surface mining and in situ approaches. Oil sands processes use substantial volumes of water known as oil sands process-affected waters (OSPW) and as per a zero-discharge policy, this water needs to be stored on location. Tailings ponds have resulted as a temporary storage solution, and remediation strategies are being developed to treat and target contaminants. Naphthenic acids (NAs), polycyclic aromatic hydrocarbons, metals, and ions are all contaminants found in OSPW. OSPW toxicity is mainly attributed to NAs and exposure has resulted in deformities, reduction in growth, and impaired development in aquatic and terrestrial species as well as immunotoxicity in macrophages. Advanced oxidation processes degrade NAs, and treated OSPW must be evaluated to determine efficacy in reducing toxicity. I propose using RAW 264.7 macrophages in a cell-based in vitro biosensor system to evaluate immunotoxicity in untreated and treated waters. Taking this further, pharmacological inhibitors can be used to understand the activation of macrophage cells by OSPW and identify OSPW-mediated receptors and receptor pathways. Macrophages use numerous receptors, like Toll-like receptors (TLRs), to detect and rapidly respond to stimuli, like bacterial lipopolysaccharides (LPS). I found that OSPW upregulates pro-inflammatory genes and advanced oxidation treatments, like electrooxidation and solar oxidation, reduces this expression. I then explored how OSPW exposure results in immunotoxicity. I found that OSPW triggers pro-inflammatory responses comparable to activation by endotoxic stimuli such as LPS. Toll-like receptor 4 (TLR4) and intracellular signaling proteins associated with TLR signaling, such as NF-κB and IRAK1/4, are implicated in both LPS- and OSPW-mediated signaling. These similarities between LPS- and OSPW-activated signaling indicate a potential role for TLR4 in detecting the immunotoxic constituent(s) of OSPW. This research enhances our understanding of how OSPW is perceived by mammalian cells and the immunotoxicity incited by OSPW. In addition, this research illustrates how RAW 264.7 macrophage cells successfully outline immunotoxicity resulting from exposure to contaminated waters and in the future, may be used to evaluate potential water treatments.

• Subjects / Keywords

  • immunotoxicity
  • OSPW
  • bioactivity
  • naphthenic acids

• Graduation date

  Fall 2024

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-sz7z-zv40

• License

  This thesis is made available by the University of Alberta Library with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.