Toxicology Letters 216 (2013) 40–46 Contents lists available at SciVerse ScienceDirect Toxicology Letters jou rn al h om epa ge: www.elsevier.com/locate/toxlet The dynamics of accumulation of PCBs in cultured adipocytes vary with the cell lipid content and the lipophilicity of the congener Sophie Bourez a , Carine Van den Daelen a , Soazig Le Lay b , Jacques Poupaert d , Yvan Larondelle a , Jean-Pierre Thomé e , Yves-Jacques Schneider a , Isabelle Dugail c , Cathy Debier a,∗ a Institut des Sciences de la Vie, UCLouvain, B-1348 Louvain-la-Neuve, Belgium b LUNAM Université, INSERM U1063, Angers, France c Université Pierre et Marie Curie – Paris 6, UMR S 872, Paris F-75006, France d Louvain Drug Research Institute, UCLouvain, B-1200, Woluwe-Saint-Lambert, Belgium e Laboratoire d’Ecologie animale et d’Ecotoxicologie, Université de Liège, Allée du 6 Août 15, B-4000 Liège, Belgium h i g h l i g h t s ◮ Accumulated amounts of PCBs in cells differ according to the in vitro model. ◮ Accumulated levels of PCBs were strongly correlated with lipid levels in cells. ◮ Dynamics of accumulation importantly differed according to the PCB congener. ◮ The log P was a major parameter governing PCB dynamics across the plasma membrane. a r t i c l e i n f o Article history: Received 31 July 2012 Received in revised form 24 September 2012 Accepted 26 September 2012 Available online 16 November 2012 Keywords: Accumulation dynamics PCBs Adipocyte models Triglycerides a b s t r a c t Lipophilic pollutants such as polychlorinated biphenyls (PCBs) accumulate in high amounts in the adi- pose tissue. Recent epidemiological studies correlate their presence in fat cells to possible alterations in the regulation of lipid metabolism. The factors governing their accumulation dynamics, storage and release in/from fat cells remain however unclear. Several in vitro models of cultured adipocytes can be used to address these questions. Nevertheless, the cell culture system as well as the PCB congener may influence the behavior of such pollutants toward adipocytes and thus the results obtained. In the present study, we compared the accumulation of 3 PCB congeners (PCB-28, -118 and -153) during a 4-h period in two common models of cultured adipocytes (mouse embryonic fibroblasts (MEFs) differentiated into adipocytes and differentiated 3T3-L1 cells). The results show that adipocytes from different models accu- mulate significantly different amounts of a same pollutant added at the same initial concentration in the culture medium. These amounts were strongly correlated to the amounts of triglycerides stored in cells. Moreover, the dynamics of accumulation varied between the three congeners, PCB-28 entering the cells more rapidly than the two other congeners. The lipophilicity of these molecules, shown by the partition coefficient (log P) appears to be a major parameter governing their uptake dynamics in fat cells. © 2012 Elsevier Ireland Ltd. All rights reserved. 1. Introduction Polychlorinated biphenyls (PCBs) are persistent environmental pollutants that tend to accumulate in lipid-rich tissues of the orga- nisms they contaminate, due to their highly lipophilic character. The adipose tissue therefore constitutes one of the most significant Abbreviations: PCBs, polychlorinated biphenyls; MEFs, mouse embryonic fibrob- lasts. ∗ Corresponding author at: Institut des Sciences de la Vie, UCLouvain, Croix du Sud, 2/L7.05.08, B-1348, Belgium. Tel.: +32 10 47 37 32. E-mail address: cathy.debier@uclouvain.be (C. Debier). internal reservoirs of such organic pollutants (Barouki and Clément, 2009; Mullerova and Kopecky, 2007). Data from recent epidemi- ological studies suggest a role for these chemicals in the basic mechanisms controlling the regulation of the energetic balance (Dirinck et al., 2011; Kim et al., 2011). PCBs and other lipophilic pollutants could indeed potentially be involved in the obesity epi- demic (Dirinck et al., 2011; Lee et al., 2011). Moreover, it has been shown that during periods of body weight loss, PCB concentration increases in the adipose tissue due to lipid mobilization (Kim et al., 2011). During such a physiological state, PCBs are also released into the blood circulation, potentially exposing the individual to the various known adverse health effects of these pollutants (Chevrier et al., 2000; Irigaray et al., 2006; Kim et al., 2011). There is thus 0378-4274/$ – see front matter © 2012 Elsevier Ireland Ltd. All rights reserved. http://dx.doi.org/10.1016/j.toxlet.2012.09.027