Fluoride Action Network


Objective: To study the effect of chronic fluorosis on neurobehavioral development, the ability of learning and memory in offspring of rats, and the antagonistic effect of antioxidant Vitamin E (Vit E).

Methods: According to body weight, forty-five 1-month-old Sprague-Dawley (SD) rats of 30 females and 15 males were divided into three groups by random number table, including control group, fluorosis and Vit E antagonistic groups (15 rats with 10 females and 5 males in every group) .Five months after establishing the animal model with chronic fluorosis and Vit E gavage treatments (fluoride <1,50,50 mg / L, respectively; Vit E 0,0,50 mg / kg, respectively), the rats were mated in 2: 1 proportion of female: male in different groups, respectively.The fertility index of female and neurobehavioral development indicators in offspring were observed.Spatial learning and memory of offspring after birth for 30 d were evaluated by using Morris Water Maze test.

Results: The female fertility index exposed to fluorosis and Vit E were not significantly different as compared to those of control group (all P> 0.05); in contrast to control groups [(6.4 + 1.8), (15.1 + 1.7) d], the time that completed the surface righting reflex [(8.1 + 1.4), (7.9 + 1.5) d] and the air righting reflex [(17.7 + 2.3), (17.2 + 1.8) d] were delayed in the offspring in fluorosis and Vit E antagonistic groups (all P <0.05 ); the completed avoidance precipice reflex and the auditory consternation did not changed significantly (all P> 0.05); In addition, compared with control and Vit E antagonistic groups [(31.74 + 17.78), (34.97 ± 15.44) s, (4.50 ± 2.51), (3.80 ± 1.87) time], the average escape latency and exploration platform at five days were decreased in 30 d offspring of fluorosis group [(42.03 + 16.45) s, (2.20 + 1.62) time].

Conclusion: Neurobehavioral development as well as learning and memory ability in rat offspring are impaired by long-term exposure to fluoride and Vit E has exhibited an antagonistic effect to the toxicities of fluoride.