Fluoride Action Network


Nine-six Wistar rats were randomly divided into four groups of 24 rats in each group (female:male = 1:1). Over a period up to 90 days, with one untreated group as controls, the other three groups were administered, respectively, high fluoride (100 mg NaF/L), high arsenic (50 mg As2O3/L), or both the same high fluoride and high arsenic concentrations in their drinking water in order to assess their effects on learning-memory ability and brain function. In comparison with the controls, learning-memory ability was depressed by high fluoride (HiF), high arsenic (HiAs), and their combination (HiF+HiAs). Brain protein contents decreased significantly in the HiF+HiAs group at days 10 and 30, and decreased cholinesterase (ChE) activities occurred in the HiF group at day 10, and in the HiF+HiAs group at days 10 and 90. Moreover, in the HiAs group, ChE activity was increased at day 30 and then decreased significantly at day 90. The total antioxidant capacity (T-AOC) in the brain was decreased in the three exposed groups. The hydrosulfide group (–SH) content of brains was decreased markedly only by HiAs. These results suggest that learning-memory ability and brain function in rats are affected by HiF and HiAs and that oxidative stress in the brain may be one of the causes of this damage.