Atrazine, a widely used herbicide banned in the European Union since 2004, has been found to accelerate brain cell aging and harm the hypothalamus, according to a new study in mice. Despite being prohibited in Europe due to groundwater contamination concerns, atrazine remains the second-most-used weedkiller globally, with over 70 million pounds applied annually in the US.
The study, published last month in Research, demonstrated significant neurotoxic effects. Researchers observed a decrease in nerve cell numbers and structural damage to neurons in the hypothalamus—a brain region critical for stress response, metabolism, and hormone regulation.
The study revealed that atrazine in mice:
Damages nerve cells (neurons) and activates microglia, immune cells in the brain that act as its “first responders” to injury, infection, or disease. Sends certain brain stem cells (hypothalamic neural stem cells, or HtNSCs) to the areas of injury in the hypothalamus. Overly activates the body’s stress response system (integrated stress response pathway), making these HtNSCs age prematurely (stop dividing and growing) and impairing their ability to maintain and repair the hypothalamus by multiplying and turning into other types of nerve cells.