Developmental fluoride exposure alters social novelty response and repetitive-like behavior in male rat offspring

Fluoride (F) is naturally present in groundwater worldwide, including Argentina. Because F crosses the placenta and is present in maternal milk, developmental exposure may interfere with brain development. However, the mechanisms underlying its developmental neurotoxicity remain unclear. This study evaluated the effects of developmental F exposure on social and repetitive-like behaviors in male rat offspring. Pregnant Wistar rats received 10 mg/L F in drinking water throughout gestation and lactation. Male offspring were assessed on postnatal day 45 using the Three-Chamber Social Test and Marble Burying Test. In the Three-Chamber Social Test, both control and F-exposed males showed significant sociability, spending more time interacting with an unfamiliar conspecific than with the empty chamber. During the social novelty phase, F-exposed males spent significantly more time interacting with the familiar than with the novel conspecific, suggesting an altered response to social novelty. F-exposed males also buried significantly more marbles than controls, indicating increased repetitive-like behavior. These findings indicate that developmental F exposure alters social novelty response and increases repetitive-like behavior in male rat offspring, supporting specific neurobehavioral effects of early-life F exposure. Further studies are needed to elucidate the underlying neural mechanisms.