The influence of a human-relevant polychlorinated biphenyl mixture on the intestinal microbiota in pregnant female mice

Polychlorinated biphenyls (PCBs) are persistent environmental contaminants with known adverse health effects. This study investigates the impact of maternal exposure to a human-relevant PCB mixture, known as the MARBLES mix, on the gut microbiome of pregnant female mice. Female C57BL/6J mice were dosed daily with the MARBLES mix at varying concentrations (0, 0.1, 1, or 6 mg/kg body weight/day) prior to mating and throughout gestation and lactation. Intestinal contents were collected to characterize the microbiome composition and predicted function, and for quantification of PCBs and their hydroxyl metabolites using gas chromatography-tandem mass spectrometry (GC-MS/MS) and liquid chromatography-high resolution mass spectrometry (LC-HRMS). MARBLES exposure influenced the abundance of microbial taxa and predicted functions while complex PCB and metabolite mixtures were detected in the intestinal content. Network analysis revealed associations between specific parent PCBs and metabolites with changes in the abundance of bacteria. These findings contribute to our understanding of how PCBs can influence gut microbiota and potentially impact maternal and fetal health and provide a foundation for future research aimed at unraveling the mechanisms underlying PCB-induced health effects during pregnancy.