Polychlorinated biphenyl toxicity in the thyroid gland of wild ungulates: an in vitro model

Abstract

<jats:p>Polychlorinated biphenyls (PCBs) are carcinogens causing endocrine disruption. While production of PCBs is now banned, wildlife exposure still occurs due to environmental contamination. We investigated thyroid toxicity in wild ungulates using three-dimensional primary thyrocyte cultures exposed to PCB 138 for 24, 48, and 72 h at concentrations ranging within 0–3000 ng/ml. Thyrocyte viability ranged within 78.71–118.34%, 98.14–104.45%, and 84.16–106.70% in fallow deer-, mouflon-, and roe deer-derived cells, respectively. Viability decreased significantly in fallow deer (<jats:italic>P</jats:italic> = 0.012) and roe deer (<jats:italic>P</jats:italic> = 0.002) thyrocytes exposed for 48 h at 30 ng/ml. While cytotoxicity ranged within 2.36–16.37%, 3.19–9.85%, and 2.76–11.21% in fallow deer, mouflon, and roe deer, respectively, only roe deer displayed significantly higher cytotoxicity at a 3 ng/ml exposure (<jats:italic>P</jats:italic> &lt; 0.05) and lower cytotoxicity at 30 ng/ml (<jats:italic>P</jats:italic> &lt; 0.01). Exposure to 30 ng/ml for 24 and 48 h induced reactive oxygen species in fallow deer. Iodide uptake at 30 ng/ml exposure increased after 24 h in fallow and roe deer, but showed a significant drop after 48 and 72 h in fallow deer, mouflon, and roe deer. Thyroxine T<jats:sub>4</jats:sub> release at 30 ng/ml exposure decreased significantly after 48 and 72 h; 24, 48 and 72 h; and 48 h in fallow deer, mouflon, and roe deer, respectively. Our findings indicate time- and species-dependent effects of PCB on performance and thyrocyte function. Use of cell culture models reduces the number of experimental specimens, increases test species welfare and replaces whole organisms with specific target cells.</jats:p>

Reproductive toxicity of heavy metals in fallow deer in vitro

“…To conclude, repeated and chronic exposure of wild game ungulates to toxic metals in their natural habitat can impair their reproduction, with reproductive function perturbation initiated at the cellular/molecular level. Importantly, the present study confirmed the utility of cell culture models for extrapolating data on adverse effects of toxic substances in wildlife species, in line with the 'Three Rs' concept of animal research (Flieger et al 2016;Kovacova et al 2016;Abdelsalam et al 2020).…”

Toxic Effects of Aroclor 1254 on Rat Heart and Thyroid and Modifying Role of Selenium Status

“…In addition, as exposure to A1254 caused a significant decrease in serum fT3 levels, it can be concluded that A1254 also has an endocrine disrupting effect in the thyroid, most possible due to disruption of hormonal feedback flow and changes in enzyme levels that metabolize thyroid hormones. Moreover, thyroidal damage, oxidative stress and/or the interactions of A1254 with thyroid hormone receptors may lead to alterations in thyroid hormone levels [16,27,34,[56][57][58][59][60][61][62][63]. However, more mechanistic studies are needed to show the exact endocrine disrupting mechanisms of different PCB congeners in the thyroid.…”

Torpor/hibernation cycle may enhance the risk of insecticides for bats: an in vitro study

“…Imidacloprid and PM are generally considered as low toxicity substances to warmblooded mammals, but very little is known about the impact of toxic substances on heterothermic bats during hibernation. The aim of the study was to assess the toxic effect of two commonly used insecticides: PM and IMI, on bat-derived cells in culture, because cell cultures represent a unique alternative tool for studying toxin (Kovacova et al 2016;Abdelsalam et al 2020;Nemcova et al 2020) and pathogen effects (He et al 2014;Flieger et al 2016) in highly protected species. As the liver represents a biotransformation organ in the metabolism of xenobiotics, liver cells are the gold standard for toxicological testing of a wide range of chemicals (Soldatow et al 2013).…”