Effects of fluoride on proliferation and apoptosis of immune cells in rats / 中华地方病学杂志

ABSTRACT

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.