The H4IIE Cell Bioassay as an Indicator of Dioxin-like Chemicals in Wildlife and the Environment

Abstract

ABSTRACT:The H4IIE cell bioassay has proven utility as a screening tool for planar halogenated hydrocarbons (PHHs) and structurally similar chemicals accumulated in organisms from the wild. This bioassay has additional applications in hazard assessment of PHH exposed populations. In this review, the toxicological principles, current protocols, performance criteria, and field applications for the assay are described. The H4IIE cell bioassay has several advantages over the analytical measurement of PHHs in environmental samples, but conclusions from studies can be strengthened when both bioassay and analytical chemistry data are presented together. Often, the bioassay results concur with biological effects in organisms and support direct measures of PHHs. For biomonitoring purposes and prioritization of PHH-contaminated environments, the H4IIE bioassay may be faster and less expensive than analytical measurements. The H4IIE cell bioassay can be used in combination with other biomarkers such as in vivo measurements of CYP1A1 induction to help pinpoint the sources and identities of dioxin-like chemicals. The number of studies that measure H4IIE-derived TCDD-EQs continues to increase, resulting in subtle improvements over time. Further experiments are required to determine if TCDD-EQs derived from mammalian cells are adequate predictors of toxicity to non-mammalian species. The H4IIE cell bioassay has been used in over 300 published studies, and its combination of speed, simplicity, and ability to integrate the effects of complex contaminant mixtures makes it a valuable addition to hazard assessment and biomonitoring studies.

Environmental Contaminants in Fish and Their Associated Risk to Piscivorous Wildlife in the Yukon River Basin, Alaska

“…A third subsample (10 g) was solvent-extracted and subjected to reactive cleanup for use in the H4IIE bioassay Whyte et al 2004). Concentrations of 2,3,7,8-tetrachlorodibenzo-pdioxin equivalent doses (TCDD-EQ; pg/g ww) were determined by slope ratio assay as modified by Ankley et al (1991).…”

Assessing the Detoxication Efficiencies of Wastewater Treatment Processes Using a Battery of Bioassays/Biomarkers

“…Also, dioxin-like chemicals are found in the environment as complex mixtures of both AhR-active and AhR-inactive congeners, and interactions between active and inactive congeners may complicate the effects on in vitro bioassay responses (Sanderson et al 1996). It was illustrated that the EROD assay may underestimate the potential toxicity of chemicals, such as PAHs and other AhR ligands that are readily metabolized (Bols et al1997;Whyte et al 2004). Large molecular weight hydrophobic PAHs can be AhR active, but they are easily metabolized or transformed in part due to their lack of halogenations (Nebert et al, 2000).…”

“…Organic compounds known to bind to the AhR include PCBs, PAHs, chlorinated dibenzodioxinx, and chlorinated dibenzofurans (Hansen and Addisson 1990), which are often found together in environmental matrices. Extensive studies have suggested that H4IIE-cell EROD assay can be used to pinpoint the sources and identities of dioxin-like chemicals (Whyte et al 2004).…”

Dioxin-like compounds in agricultural soils near e-waste recycling sites from Taizhou area, China: Chemical and bioanalytical characterization

“…Numerous studies have utilized in vitro bioassays based on ethoxyresorufin-O-deethylase (EROD) induction in rat hepatoma cell line H4IIE and other cell lines to evaluate the relative potencies of compounds in inducing CYP1A enzyme system (Behnisch et al, 2001a;Giesy et al, 2002;Qiao et al, 2006). This type of enzymatic assay has undergone a number of improvements since its initial stages, and has been proven to be a useful tool for characterizing complex mixtures of dioxin-like contaminants (Behnisch et al, 2001a,b;Giesy et al, 2002;Whyte et al, 2004). However, unlike chemical analysis, in vitro or in vivo bioassays generally cannot precisely quantify the concentrations of chemicals present, nor can they identify the exact compounds causing the response.…”