Effects of embryonic exposure to fluoride on bone development of zebrafish / 中华地方病学杂志

ABSTRACT

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.