Fluoride exposure during development affects both cognition and emotion in mice

- The developmental fluoride exposure to mice affects their emotional behaviors.
- The developmental fluoride declines both spatial and non-spatial cognition of mice.
- The high fluoride reduces the exercise tolerance of mice.

Previous studies have suggested that sodium fluoride (NaF) may have adverse effects on neurodevelopment. In the present study, we evaluated developmental neurotoxicity by assessing in cognitive function and emotional behavior in BalB/C mice treated with NaF. Mice were weaned at 4 weeks, and water or different NaF concentrations (2, 5, or 10 mg/L in drinking water) were provided for 4 weeks. We found that exploration preference in the novel object recognition test was significantly altered in mice treated with 5 and 10 mg/L NaF compared with the water-treated control animals. Furthermore, mice treated with 5 and 10 mg/L NaF showed significantly longer escape latencies, less time in the target quadrant, and fewer platform-crossing numbers in the Morris water maze compared to those in the control group. In addition, mice treated with 10 mg/L NaF spent a lower percentage of time in the open arms in the elevated-plus maze, while no significant changes were noted in the open and close arm entries or the total arm entries. We also found that the cumulative immobility time in the tail suspension test was longer in mice treated with 5 and 10 mg/L NaF compared to the control group. Only 10 mg/L NaF-treated mice showed longer immobility time compared with the control group. Collectively, our data indicate that developmental exposure to NaF induces cognitive deficits and anxiety-depression-like behaviors in mice.