Objective: To investigate the changes of oxidative stress level in brain tissues and serum, and learning and memory in rats with oxidative stress level in nerve damage in chronic fluorosis.
Methods: The rats were randomly divided into 3 groups according to the body weight, eight rats in each group, i.e., control group, drinking water containing less than 0.5 mg/L of fluoride; lower fluoride exposure group, drinking water containing 5 mg/L of fluoride; higher fluoride exposure group, drinking water containing 50 mg/L of fluoride. The animals were examined six months after initiating the experiment. The total antioxidant capacity (T-AOC) and malondialdehyde (MDA), as well as learning and memory, were measured.
Results : Escape latency in higher fluoride exposed group[ (14.37±3.48)s] was significantly higher than that of controls[ (5.84±1.87)s] and exposed te lower fluoride [ (7.18±1.42)s], the difference being statistically signifieant(P<0.05). As compared with controls[ (2.17±0.11)× 103 U/L , (0.79±0.11)×103 U/g Pr] ,the rats exposed to higher fluoride and lower fluoride exhibited lower levels of T-AOC [(1.37±0.27)×103 U/L,(0.24±0.06)×103 U/g Prand (1.20±0.14) x 103 U/L,(0.41 ~ 0.10)×103 U/g Pr], the difference being statistically signifieant(P<0.05). As compared with controls[ (2.34±0.16) mmoL/L, (2.97±0.11)mmol/g Pr] and low fluoride exposed group[ (2.68±0.33)mmoL/L, (3.38±0.21)mmol/g Pr], higher level of MDA were observed in higher fluoride exposed group[ (3.72±0.59)retool/L, (4.01±0.21)mmol/g Pr], the difference being statistically significant(P<0.05).
Conclusion: The results indicated that higher amount of fluoride induced an increased level of oxidation, which might result in the decreased capacity of intelligence of rats with fluorosis.