Exposure to Plastics: The Effect on Rat Brain Development
PLASTIC exposure is a global issue, the implications of which are still being discovered, both environmentally and medically. It has long been established that phthalates, a chemical compound added to plastics to give them a variety of desirable properties, can travel across the placenta to a developing fetus and can also be transmitted to offspring via breast milk. Now, a study from the University of Illinois at Urbana–Champaign, Champaign, Illinois, USA, has shown a link between exposure to phthalates and stunted brain development in rats.
Previous studies around this topic yielded mixed results, and thus the researchers set out to create a study that would mimic the levels of exposure experienced in human mothers. Using data taken from pregnant women, the researchers laced cookies with similar levels of phthalates, which were then fed to the study rats. These rats were divided into three groups, no dose (control), low-dose, and high-dose, and were given a cookie daily during pregnancy and for 10 days while lactating.
Following examination of the offspring’s brains, the study revealed a significant lack of neurons and synapses in the rat’s medial prefrontal cortex (mPFC) in both groups exposed to phthalates. Impairment of the mPFC’s development can have a major impact on high-level cognitive functions, such as memory, decision-making, error detection, conflict monitoring, and cognitive flexibility. Upon reaching adulthood, the rat’s cognitive flexibility was tested using a set-shifting task, the results of which showed the expected impairment. “These results may have serious implications for humans given the mPFC is involved in executive functions and is implicated in the pathology of many neuropsychiatric disorders,” explained Prof Janice Juraska, University of Illinois at Urbana–Champaign.
Further studies are required to better understand the true impact of phthalate exposure in humans, but these results will no doubt aid the progression of future scientific understanding of the neurological effects of exposure to these potentially dangerous compounds