A rat model of human prenatal exposure to an environmentally relevant mixture of phthalates – endocrine-disrupting chemicals – and a high-fat diet (HFD) shows that said mixture can impact social behavior, according to a study recently published in Endocrinology.
Researchers led by Janice M. Juraska, PhD, of the University of Illinois in Champaign, point out that diet is presumed to be the main source of human exposure to phthalates, since these chemicals are used during food production and are found in packaging. “Moreover,” the authors write, “fatty foods such as oils, dairy, meat, and fish contain the highest level of phthalates, which is of concern as calorically dense and high-fat foods are readily available in the developed world.” They go on to write that exposure to these chemicals and HFD can separately increase oxidative stress and inflammation, so it’s important to study these affects.
The researchers fed dams a mixture of phthalates and either a control diet or HFD from gestation through postnatal day (P) 10. They found that the males’ perinatal exposure to the mixture decreased their prepubertal body weight and periadolescent social play behavior (pouncing and pinning). “A dose-specific effect from phthalates with HFD was also seen in increased time alone in females during social play,” the authors write.
What’s more, the dams that ate HFD consumed more calories, had a greater gestational weight, and tended to lick and nurse their pups more, which led to their pups having increased body weight. “There also was a tendency for increased oxidative stress markers at P10 within the medial prefrontal cortex of males exposed to the relatively high dose of phthalates and HFD. Effects on gene expression were inconsistent at P10 and P90 in both the medial prefrontal cortex and hypothalamus,” the authors write.
Based on these results, the researchers conclude that exposure to phthalates and HFD had independent effects on the animals that only sporadically interacted other than in the oxidative stress levels in the males. “The effects due to the mixture of phthalates were often small and either dose- or sex-specific. This study demonstrates that perinatal exposure to an environmentally relevant mixture of phthalates can modestly influence later behavior, without regard to diet,” the authors write.