Among the environmental pollutants that can negatively affect health are endocrine disruptors (EDCs), which are chemical substances that have the ability to alter the body’s hormonal balance. The problem is that they are found in practically all ecosystems and can continue to cause problems for a long time, especially when exposure occurs during the prenatal period.
One of the aspects being evaluated is how these substances affect the neuroendocrine system of the brain, which regulates important physiological functions and behaviors, and which develops differently in men and women under the influence of hormones such as testosterone and estradiol. Exposure to endocrine disruptors during the early phases of development when key changes in sexual differentiation occur can alter these functions and behaviors, although the effects do not always manifest until later in life.
New research published in the Journal of the Endocrine Society has analyzed the risks associated with exposure to polychlorinated biphenyls (PCBs), a type of endocrine disruptor that was banned decades ago, but whose chemical properties have allowed it to persist in the environment. environment, and has found that exposure to this toxic during the prenatal period can cause behavioral problems in rats.
What are PCBs and what risks do they have for health?
Polychlorinated biphenyls were used in industrial and commercial applications and can accumulate in the tissues of organisms and remain there for a long time. Recent research has shown that developmental exposure to PCB mixtures, such as Aroclor 1221 (A1221), can affect gene and protein expression in the brain, influence reproductive aging, modify neurogenesis processes, and alter social and behavioral behaviors. of anxiety.
In the brain, kisspeptins are a group of peptides essential for functions such as the onset of puberty, pregnancy and the regulation of reproduction in response to stress or nutritional status. These molecules act on the hypothalamic-pituitary-gonadal axis, a key pathway for the production of sex hormones and the formation of gametes. Kisspeptin neurons, located in specific areas of the hypothalamus, interact directly with other cells to coordinate these processes.
Researchers have found alterations in social behaviors, partner preferences, and anxiety levels associated with PCB exposure
However, these neurons are also sensitive to sex hormones, especially estradiol, which makes them vulnerable to the effects of EDCs with estrogenic properties. This raises the possibility that early exposure to PCBs may interfere with their development and function, with consequences for reproductive health.
Impact of pollutants on brain and reproductive health
Recent studies suggest that men and women may respond differently to exposure to EDCs. Brain development and function are determined by sex differences, which also influence how these pollutants affect the hypothalamus, a key region in maturation and reproductive success. Understanding these differences is essential to predict the impact of pollutants on long-term brain and reproductive health.
The researchers have explained in their article that in the study they have analyzed how prenatal exposure to A1221 affects the development of kisspeptin neurons, body weight, anogenital distance and the onset of puberty in rats, considering the differences between sexes and changes over time. Although kisspeptin systems showed some resistance to the effects of A1221, we observed specific alterations, such as an increase in prodynorphin in a brain region of male rats.
Although early exposure to A1221 did not trigger drastic changes in the neuroendocrine system, they say they identified small adjustments in different parameters that, combined, suggest modifications in the reproductive profile. Furthermore, hormonal changes induced by A1221 during early life could reorganize the brain and contribute to differences in sex-related behaviors.
In fact, they state that they have found alterations in social behaviors, partner preferences, and anxiety levels associated with exposure to PCBs. In addition, they have identified changes in gene expression and the formation of new neurons in areas of the brain related to sexual differentiation.
These findings underline the importance of studying the effects of low doses of EDCs, as they better reflect the real risks to animals and people. “In addition, our observations in rats provide valuable information on how PCBs affect reproductive physiology in different species, laying the foundation for future research that can improve our understanding and reproductive health,” they conclude.
