Bone properties of mink (Neovison vison) exposed to environmentally relevant levels of PCB

An alarming reduction in the numbers of several species of seals in the Baltic Sea was observed during the second half of the 1900s. Organochlorines, particularly PCBs, were found to cause the decline, inducing sterility and severe bone loss. If bone tissue is affected by PCBs, bone could be used as a biomarker for exposure to environmental contaminants. To isolate the effects of PCBs from other factors, experimental studies have been conducted on model species, such as mink. In this study, 58 mink femurs from three different treatment groups and one control group were analysed. Altogether 14 different parameters were measured using peripheral quantitative computed tomography (pQCT). Mink treated with a low dose of PCBs develop increased content, area and thickness of cortical bone. Mink treated with a high dose of PCBs do not show the same effects but have a cortical area similar to that of non-exposed animals. The trabecular density and content is increased in all groups that have been exposed to PCBs. The observed effects may be the result of dioxin-like PCBs binding to the aryl hydrocarbon receptor (AhR). The activation of AhR leads to disruptions in endocrine systems, that in turn impacts bone modelling and remodelling. However, other pathways cannot be ruled out, including the effects of non-dioxin-like PCBs. Further analyses are needed in order to fully understand how PCBs affect bone tissue properties