Expression of Sirtuin1 gene in brain tissues of fluorotoxic rats / 中华地方病学杂志

ABSTRACT

Objective To investigate the expression of Sirtuin1 (SIRT1) in brain tissue of rats with different doses of fluorosis-induced brain injury.Methods Forty-eight clean SD rats were divided into 4 groups based on body weight (90-100 g) via the random number table method:the control group (normal feed containing fluoride 4.5 mg/kg),low fluoride groups (feed containing fluoride 25.0 mg/kg),middle fluoride groups (feed containing fluoride 50.0 mg/kg),high fluoride groups (feed containing fluoride 100.0 mg&g),twelve rats in each group,half male and half female.Rats in each group drank tap water freely.Low,middle and high fluorine groups were free to eat the designated different formulations of raw coal and mixed peat baked corn feed,other feed ingredients were the same as those in control group,the rats were sacrificed at 90 d of fluorine exposure.At 7 d before the rats were sacrificed,Morris water maze and platform experiment were employed to test the ability of learning and memory in rats.Take the brain tissue and thigh long bones after the rats were sacrificed,immediately.The fluorine ion selective electrode method was used to detect urinary fluoride and fluorine content in bone in rats.The brain SIRT1 mRNA and protein expression levels were detected by Real-Time PCR and Western blotting,respectively.Results In the space exploration experiments,the mean time to first passage of platform of the rats in control group and low,middle and high fluorine groups were (9.8 ± 3.5),(15.8 ± 5.1),(22.2 ± 7.9) and (30.5 ± 8.5) s,respectively.The differences between groups were statistically significant (F =10.853,P ＜ 0.05).The number of passed through the platform of the rats in control and low,middle and high fluorine groups were (5.2 ± 2.1),(3.3 ± 1.6),(1.3 ± 1.1) and (1.2 ± 0.8) time/60 s,respectively.The differences between groups were statistically significant (F =10.105,P＜ 0.05).In the control group and low,middle and high fluoride groups,the resting time of the original platform quadrant were (30.5 ± 9.8),(22.7 ± 4.6),(13.8 ± 4.8) and (7.0 ± 2.4) s,respectively.The differences between groups were statistically significant (F =17.433,P ＜ 0.05).And the middle,high fluoride groups compared with the control group was significantly different (P ＜ 0.05).With increase of fluoride dosage,the first time to cross the platform gradually extended,the number of crossing the platform and the original platform quadrant dwell time decreased gradually,the differences between the middle,high fluoride groups and the low fluoride group were statistically significant (P ＜ 0.05).The mRNA expression of SIRT1 in control group and low,middle and high fluoride groups were 0.979 ± 0.088,0.907 ± 0.050,0.426 ± 0.073,0.219 ± 0.092,respectively.The differences between groups were statistically significant (F =136.837,P ＜ 0.05).The levels of SIRT1 protein in control group,low,middle and high fluoride groups were 1.224 ± 0.139,0.988 ± 0.096,0.581 ± 0.084 and 0.269 ± 0.066,respectively.The differences between groups were statistically significant (F =107.961,P ＜ 0.05).The levels of SIRT1 mRNA and protein were gradually decreased with increase of fluoride dose in the low,middle and high fluoride groups (P ＜ 0.05).Conclusions Fluorosis can affect the learning and memory ability of rats.SIRT1 mRNA and protein expressed in rat brain is decreased,which is more obvious with the increase of fluoride dose.