Exposure to environmental pollutants can cause alterations in brain development that affect sexual development and fertility for several generations, a study has found. Researchers from the University of Liege in Belgium monitored the sexual development of three generations of rats. Pregnant rats were exposed to a mixture of common endocrine-disrupting chemicals (EDCs), at doses equivalent to those commonly experienced by people.
Their offspring showed impairments in sexual development and maternal behaviour that were passed on through several generations. The female rats born in the first and second generation showed impairments in their care for their own pups.
However, the female rats in the second and third generation exhibited a delayed onset of puberty and altered reproductive cycle and ovarian follicle development, indicating that their fertility was affected, even though they were never themselves exposed to the EDCs. These changes were associated with altered gene expression in their brains that are known to affect how reproductive hormones are regulated.
"Our results raise real concerns about the effects of these pollutants in our environment. We found effects of EDCs in generations of animals that had not been directly exposed to the chemicals," said Anne-Simone Parent from the University of Liege.
"We exposed the parent generation only and found long-term effects on fertility. Of course, in everyday life this would not happen and exposure to these harmful chemicals would continue, which means even more damage could be done," said Parent.
The findings suggest that current levels of EDCs in our environment may already be causing long-lasting harm and that people and agencies should take measures to minimise exposure.
Endocrine-disrupting chemicals can interfere with the normal function of our hormones and have previously been associated with infertility and altered sexual development in animals and people, researchers said.
We are exposed to hundreds of these pollutants in our daily lives, as they are used in the manufacture of plastics, pesticides and medicines.
However, the extent of damage being done to our health and the consequences to future generations remains unclear. Rodent studies have suggested that exposure to EDCs can affect brain development through several generations but the generational effects on sexual development and reproduction have not previously been investigated.
"These findings raise questions about the legacy we are leaving future generations," Rodriguez said.