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Updated: Jul 14, 2026
Long-term Behavioral and Reproductive Consequences of Embryonic Exposure to Low-dose Toxicants
Published on: March 6, 2018
Prenatal exposure to 3,3',4,4',5-pentachlorobiphenyl (PCB126) promotes anxiogenic behavior in rats
Kensuke Orito1, Nanae Gotanda, Masaru Murakami
1Department of Pharmacology, Azabu University School of Veterinary Medicine, Kanagawa, Japan. oritok@azabu-u.ac.jp
Insights
Prenatal exposure to polychlorinated biphenyls (PCBs) can induce anxiety-like behaviors in offspring. This study shows PCB126 exposure in pregnant rats led to altered stress responses and emotionality in male pups.
Area of Science:
- Environmental toxicology
- Neuroendocrinology
- Developmental neurobiology
Background:
- Polychlorinated biphenyls (PCBs) are persistent environmental contaminants with known endocrine and neurotoxic effects.
- Human epidemiological studies link prenatal PCB exposure to cognitive and motor deficits in children.
- The impact of prenatal PCB exposure on offspring emotionality remains largely uninvestigated.
Purpose of the Study:
- To investigate the effects of prenatal exposure to a specific PCB congener, 3,3',4,4',5-pentachlorobiphenyl (PCB126), on emotionality in male rat offspring.
- To assess PCB126-induced changes in anxiety-like behaviors and the hypothalamic-pituitary-adrenal (HPA) axis stress response.
Main Methods:
- Pregnant rats were administered PCB126 (30 microg/kg) or vehicle (corn oil) orally on gestational day 15.
- Male offspring were tested at 4-5 weeks old using behavioral assays: open field test and social interaction test.
- Serum corticosterone levels were measured following acute stress (forced swim test).
Main Results:
- Prenatal PCB126 exposure resulted in increased anxiogenic behavior in the open field test (reduced center time, rearing; increased grooming).
- Social interaction was reduced in PCB126-exposed offspring, indicating heightened anxiety.
- The HPA axis response to stress, measured by corticosterone levels, was potentiated in PCB126-exposed rats.
Conclusions:
- Prenatal exposure to PCB126 induces anxiogenic behavior and alters stress reactivity in male rat offspring.
- Dysfunction of the hypothalamic-pituitary-adrenal axis is implicated as a contributing factor to PCB126-induced emotional abnormalities.
- These findings highlight potential long-term emotional consequences of developmental PCB exposure.
Abstract:
Polychlorinated biphenyls (PCBs) are environmental contaminants that have adverse effects on the endocrine and nervous systems. As they are still detected in breast milk and adipose tissue in humans, the accumulated PCBs may transfer from mothers to children and damage central nervous system. It is revealed from epidemiological studies that cognitive and motor functions were damaged in children born to mothers who ingested PCBs-contaminated foods. However, it remains unclear whether prenatal exposure to PCBs affects emotionality. In the present study, we therefore examined the effect of prenatal exposure to 3,3',4,4',5-pentachlorobiphenyl (PCB126) on emotionality in rats by focusing on anxiogenic behavior and response of the hypothalamus-pituitary-adrenal axis to stress. Pregnant rats were treated orally with PCB126 at a dose of 30 microg/kg or corn oil, its vehicle, on gestational day 15, and their male offspring were subjected to the following experiments at 4-5 weeks old. In an open field test, rats with prenatal exposure to PCB126 showed anxiogenic behavioral responses, including decrease in time spent in the center of an open field and the number of rearings and extension of grooming duration. Interactive behavior, which is an index of anxiety level, was shortened in the social interaction test. The increase in the serum corticosterone level induced by forced swim stress was facilitated by prenatal exposure to PCB126. This evidence suggests that PCB126 may exert anxiogenicity on the offspring of exposed dams, and dysfunction of the hypothalamus-pituitary-adrenal axis may at least in part contribute to this abnormality.
