Objective: To study the role of fluorosis on learning and memory in rat and its possible mechanisms; to explore the correlation between cholinesterase activity and the level of intelligence.
Methods: SD rats divides into 3 group of stochastically according to the sex and the body weight, control group treated with drinking water containing fluoride less than 1 mg/L, lower fluoride exposed group with drinking water containing fluoride 5 mg/L, and higher fluoride exposed group with drinking water containing fluoride 50 mg/L. The ability of learning and memory and cholinesterase activity were detected in the third month after experiment.
Results: Escape latency in higher fluoride exposed group [(17.55±1.51)s] was significantly higher than that of controls group [(12.07±0.97)s], the difference being statistically significant (P?0.05). The numbers of crossing platforms in higher fluoride exposed group [(2.88±0.35)times] were lower than those of controls group[(4.00±0.50)times], but the difference was not statistically significant (P?0.05). The activities of acetylcholinesterase and butylcholinesterase in higher fluoride exposed group [(1.41±0.19),(0.49±0.07)kU/g] were significantly lower than those of controls[(1.88±0.13),(1.04±0.16)kU/g], the difference had statistical significances (P?0.05).
Conclusions: The results indicate that excessive fluoride can decrease the level of intelligence of rats, the declined activities of cholinesterase may be the possible pathogenetic mechanism.