ABSTRACT
Objective To study the effect of different concentrations of fluoride on cultured human umbilical vein vascular endothelial cells(HUVEC). Methods Different doses of sodium fluoride (NaF) were added to HUVEC culture medium, fluoride concentrations were 0(control), 100,400,700,1000,2000 μmol/L, respectively,6 re-set hole in each group. After continuous culture for 48 h, cells and culture medium were collected. Cell morphology was studied by Wright-Giemsa staining; cells apoptosis was determined by acridine orange fluorescence staining; cell activity was measured by methyl thiazolyl tetrazolium (MTT) assay; superoxide dismutase (SOD),glutathione peroxidase(GSH-Px) activity, malonaldehyde(MDA) content, induced nitricoxide synthase(iNOS), and endothelia nitricoxide synthase(eNOS) activity in cell culture medium were determined by spectrophotometry; cell iNOS mRNA and eNOS mRNA expression were detected by RT-PCR; intercellular adhesion molecule-1 (ICAM-1)and vascular cell adhesion molecule-1 (VCAM-1) levels were detected by double antibody sandwich ELISA method.Results With increased dose of fluoride, HUVEC cells decreased, the structure changed. In 400 - 2000 μmol/L group, the SOD activity[(6.627 ± 0.213), (6.668 ± 0.152), (5.935 ± 0.122), (4.755 ± 0.182)kU/L] was lower than those of the control group[(7.457 ± 0.398)kU/L, P ＜ 0.05 or ＜ 0.01], GSH-Px activity[(481.284 ± 43.785),(492.223 ± 16.474), (382.762 ± 25.167), (293.687 ± 24.881 )kU/L] was also lower than those of the control group [(585.078 ± 47.323)kU/L, P ＜ 0.05 or ＜ 0.01], MDA level[(0.609 ± 0.011 ), (0.646 ± 0.016), (0.852 ± 0.013),(1.188 ± 0.045)nmol/L] was higher than those of the control group[(0.512 ± 0.027)nmol/L, P ＜ 0.05 or ＜ 0.01];iNOS activity[(3.604 ± 0.115), (3.615 ± 0.075), (3.848 ± 0.103), (4.275 ± 0.079)kU/L] also was higher than those of the control group[(2.798 ± 0. 136)kU/L, all P ＜ 0.01], iNOS mRNA expression increased, eNOS activity [(5.539 ± 0.079), (5.503 ± 0.064), (5.226 ± 0.142), (4.809 ± 0. 107)kU/L] decreased compared to those of control group[(5.996 ± 0.155)kU/L, P ＜ 0.05 or ＜ 0.01], eNOS mRNA expression decreased; ICAM-1 levels [(0.852 ± 0. 102), (0.886 ± 0.061 ), (0.961 ± 0.158), (1.418 ± 0. 167)μg/L] increased compared to those of the control group[(0.687 ± 0.046)μg/L, P ＜ 0.05 or ＜ 0.01], VCAM-1 levels[(2.719 ± 0.197), (2.946 ± 0.167),(3.173 ± 0.225 ), (3.613 ± 0. 153 ) μg/L] was higher than those of the control group [(2.375 ± 0.067 ) μg/L, all P ＜0.01]. Conclusions High concentrations of fluoride reduce the activity of antioxidant enzymes, which leads to metabolic disorders of nitric oxide and abnormal cytokines expression, thereby inhibiting vascular endothelial cell growth, structural change and induced apoptosis. This is an important factor in high fluoride-induced vascular endothelial injury.
ABSTRACT
Objective To study morphological changes of rabbit artery endothelial cell injury and atherosclerosis caused by high fluoride and the role of selenium. Methods Twenty healthy male New Zealand white rabbits, body weight (2.0 ± 0.5)kg, were randomly divided into control group(drinking deionized water, fed basic diet), fluoride group(drinking fluoride 100 mg/L deionized water, fed basic diet), selenium group(drinking selenium 1 mg/L deionized water, fed basic diet), fluoride plus selenium group(drinking fluoride 100 mg/L deionized water, selenium 1 mg/L of deionized water, fed basic diet). The experimental period was 6 months. At 0, 3, 6 months of the experiment, serum fluorine and selenium levels were determined. At the end of the experiment,thoracic aorta was collected to observe its pathology and ultrastructural changes. Results Serum fluoride was significantly higher at the 3rd and the 6th month of experiment(all P ＜ 0.01 ) in fluoride group[ (0.589 ± 0.146),(0.772 ± 0.175)mg/L] and fluoride plus selenium group[ (0.502 ± 0.094), (0.693 ± 0.158)mg/L] than in control group[ (0.174 ± 0.002), (0.208 ± 0.031 )mg/L] and serum fluoride was significantly higher at 6 months than at 3 months(P ＜ 0.05 ) in fluoride group. Serum selenium was significantly higher at the 3rd and the 6th month of experiment (all P ＜ 0.01 ) in selenium group[ (0.252 ± 0.022), (0.319 ± 0.052)mg/L] and fluoride plus selenium group[ (0.239 ±0.016), (0.294 ± 0.018)mg/L] than in control group[(0.135 ± 0.014), (0.167 ± 0.019)mg/L], and serum selenium was significantly higher at the 6th month than at 3rd month of experiment in selenium group(P ＜ 0.05). Endothelial cell apoptosis indices were (4.92 ± 1.32)%, (30.30 ± 6.80)%, (6.57 ± 2.14)% and (14.29 ± 2.99)%, respectively in control group, fluoride group, selenium group and fluoride plus selenium group. Their main effect of fluorine and selenium was statistically significant (F = 106.833,20.082, all P ＜ 0.01 ). There were antagonistic effect between fluoride and selenium(F = 30.402, P ＜ 0.01 ). Pathological changes of rabbit aortic endothelial cells in fluoride group included endothelial with attached fibrin and red blood cells, and structural of the cells changed, with serious vascular injury; in fluoride plus selenium group apoptosis of endothelial cells decreased, with reduced number of attached red blood cells and fibrin, endothelial cell structure normal, the extent and scope of vascular damage significantly reduced. Conclusions Appropriate amount of selenium inhibits the apoptosis of endothelial cells induced by high fluoride, reduces aortic structural damage caused by high fluoride, and maintains the integrity of endothelial cells, thereby antagonizes the vascular damage and atherosclerosis induced by high fluoride.