Effects of fluorosis on levels of cystathionine beta-synthase and hydrogen sulfide in rats / 中华地方病学杂志

ABSTRACT

Objective To observe the effects of fluorosis on the levels of endogenous cystathionine beta-synthase (CBS) and hydrogen sulfide (H2S) in rats.Methods According to body weight,forty-eight Sprague-Dawley rats (body weight 105-180 g) were divided into three groups by a random number table(16 rats in each group,half male).Fluorine contents of the feed in control group,low-fluoride group and high-fluoride group were 9.80,15.40 and 23.80 mg/kg.After 6 months of fluorine exposure,the fluorine contents of urine and bone were determined by the method of fluorine ion-selective electrode ; H2S levels in serum and brain and the activity of CBS in brain were detected by methylene blue; and protein expression of CBS was detected by Western blotting.Results Compared with control group,dental fluorosis was found in rats of low-fluoride and high-fluoride groups.The differences of fluorine contents of urine and femur were statistically significant between groups(F =65.16,67.93,all P ＜ 0.05).The urinary and femoral fluorine in low-fluoride groups [(5.25 ± 0.45)mg/L,(1 196.54 ± 72.78)mg/kg] and high-fluoride groups[(13.17 ± 0.98)mg/L,(2 656.61 ± 170.12)mg/kg] were higher than those of control groups [(3.64 ± 0.20)mg/L,(870.71 ± 71.51)mg/kg,all P ＜ 0.05],and the increases were in a dose-dependent fashion(all P ＜ 0.01).The differences of H2S contents in serum and brain were statistically significant(F =4.83,1 456.13,all P ＜ 0.05).The H2S content in serum was higher in high-fluoride group [(17.64 ± 2.38) μ mol/L] than that of the control group [(10.29 ± 0.74) μ mol/L,P ＜ 0.01].The H2S contents in brain were higher in the low-fluoride [(364.74 ± 2.06)μmol/L] and high-fluoride groups [(513.43 ± 4.18) μmol/L] than those of the control group[(314.94 ± 0.72)μmol/L,all P ＜ 0.01],and the increase was in a dose-dependent fashion (P ＜ 0.01).The difference of CBS activity was statistically significant between groups (F =760.63,P ＜ 0.01).The CBS activities were lower in low-fluoride [(438.90 ± 2.83) mmol· kg-1· min-1] and high-fluoride groups [(529.83 ± 2.37)mmol· kg-1· min-1] than those of the control group [(596.33 ± 2.75) mmol · kg-1· min-1,all P ＜ 0.01],whereas the protein expression of CBS in brain in high-fluoride group (1.49 ± 0.08) was higher than that of the control group (1.19 ± 0.06,P ＜ 0.05).Conclusion Chronic fluorosis can affect the levels of endogenous CBS and H2,S,and the increases are in a dose-dependent fashion in addition to CBS activity.