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Objective To study the effects of different fluoride concentrations on proliferation and apoptosis of rats' immune cells,and to explore the effects of fluoride on immune function.Methods Sixty male Wistar rats were randomly divided into four groups,and the concentrations of NaF in drinking water for each group (15 rats in each group) were 0,50,100,and 150 mg/L,respectively.They were freely fed water and commercial standard chow.All rats were sacrificed after 12 weeks.Thymus index was calculated.Lymphocyte proliferation activity in the blood was detected by Cell Counting Kit-8 assay.The apoptosis of monocytes in blood was detected by Annexin V/PI method.The apoptosis of lymphocytes in spleen and thymus was detected by Tunal method.Results After 12 weeks of fluoride exposure,the difference in the thymus immune organ index between the four dose groups was statistically significant (F =6.50,P ＜ 0.05);after 12 weeks,the thymus immune organ index of the low and middle dose groups was significantly lower than that of the control group (0.70 ± 0.19,0.84 ± 0.18 vs 1.16 ± 0.33,P ＜ 0.05).There were significant differences in B and T lymphocyte viability between the four dose groups (F =539.97,4.92,P ＜ 0.05).The viability of B lymphocyte in the blood of the middle dose group was significantly lower than those of control group and the low dose group [(58.09 ± 4.59)％ vs (100.00 ± 9.01)％,(106.70 ± 4.82)％,P ＜ 0.05].The viabilities of T lymphocyte in the blood of the low and middle dose groups were significantly lower than that of the control group [(81.11 ± 2.93)％,(75.68 ± 2.34)％ vs (100.00 ± 34.02)％,P ＜ 0.05].The apoptosis rates of blood mononuclear cells in the fluoride-treated groups were significantly increased than that of control group [(48.00 ± 7.45)％,(47.26± 5.94)％,(48.20 ± 3.40)％ vs (32.50 ± 13.70)％,P ＜ 0.05).Immunohistochemistry results showed that the number of apoptotic lymphocytes in the spleen and thymus increased significantly in high dose group.Conclusion Fluoride can reduce the thymus immune organ index of rats,affect the proliferation of lymphocytes in blood,thymus and spleen,and promote apoptosis of lymphocytes,thus affecting the immune function.
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Objective To study the effect of fluoride exposure on bone growth in zebrafish.Methods The zebrafish larvaes at 3 days post fertilization (3 dpf) were exposed to the conventional fish water and 25,50,100 mg/L of NaF for 5 days until the skeletal bone was formed (8 dpf) and the temperature was kept at 28 ℃.The fluoride content of zebrafish embryos was detected by F-ion selective electrode.The fluoride exposure model was re-established as the control group (0.0 mg/L),the low doses group (0.5,1.0,4.0 mg/L) and the high doses group (50.0,100.0 mg/L).The survival rates of the zebrafish embryos were calculated and the morphology of zebrafish embryos was observed under 40 times microscope.The zebrafish skeleton was stained with alizarin red.The staining areas and the integrated optical density (IOD) of the bone staining were quantitatively analyzed by digital microscope to analyze the sclerotic and osteoporosis of the skull.Results The fluoride contents of the control group and 25,50,100 mg/L NaF groups were (0.32 ± 0.01),(0.63 ± 0.01),(0.86 ± 0.02) and (1.21 ± 0.01) μg/150 embryos.Compared with the control group,the fluoride contents of zebrafish embryos in fluoride exposed groups were increased (P ＜ 0.05),and the dose-response relationship was obvious.The survival rates of zebrafish embryos in control group and fluoride exposed groups were 96.67％,96.67％,96.67％,98.33％,98.33％ and 98.33％.There was no significant difference among different groups (x2 =7.309,P ＞ 0.05);under a 40 times microscope,there were no obvious deformities of the spin in different groups;the areas of the alizarin red staining of the skull were 84 380.51 ± 11 711.41 in the control group,92 592.16 ± 7 143.81,92 164.85 ± 10 136.18 and 95 112.26 ± 13 721.91 in the low doses exposure groups (0.5,1.0,4.0 mg/L NaF),67 778.92 ± 8 597.11 and 64 272.93 ± 9 302.57 in the high doses groups (50.0,100.0 mg/L NaF).The areas of the alizarin red staining of the skull in the low doses exposure groups were significantly higher than that of the control group (P ＜ 0.05),while the high doses exposure groups were lower (P ＜ 0.05);the IOD of the alizarin red staining of the skull was 25 094.13 ± 6 571.86 in the control group,29 754.95 ± 3 836.45,28 747.36 ± 4 677.86 and 30 776.49 ± 5 589.63 in the low doses exposure groups (0.5,1.0,4.0 mg/L NaF),19 263.10 ± 4 754.72 and 18 202.58 ± 4 897.15 in the high doses groups (50.0,100.0 mg/L NaF).The IOD of the alizarin red staining of the skull in the low doses exposure groups was significandy higher than that of the control group (P ＜ 0.05),while the high doses exposure groups was lower (P ＜ 0.05).Conclusion Low doses of fluoride exposure may cause bone sclerosis in zebrafish embryos,while the high dose of fluoride exposure may cause osteoporosis.
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In 2012,General Office of the State Council forwarded the'12th Five-Year Plan'on National Prevention and Control of Endemic Diseases,which was jointly developed by the Former Ministry of Health,Development and Reform Commission,and Ministry of Finance.During the 12th Five-Year Plan period,the national prevention and control of endemic diseases had made steady progress.This article mainly summarized the progress made in prevention and control of endemic diseases in China during the 12th Five-Year Plan period.The main problems encountered in prevention and control of endemic diseases in China were discussed.The prevention and key research tasks of the 13th Five-Year Plan on national prevention and control of endemic diseases were introduced.In the 13th Five-Year Plan,key issues in prevention and control of endemic diseases will be the existing main problems,to carry out targeted prevention and control,and to develop scientific and accurate prevention and control plan according to law.