Impact of fluorine and aluminum and both action combined on the number of rat osteoclasts and bone resorption cultured in vitro / 中国地方病学杂志

ABSTRACT

Objective To determine the impact of fluorine and aluminum,and both action combined on the number of rat osteoclasts and bone resorption cultured in vitro and to explore its mechanisms.Methods The osteoclasts and bone marrow stromal cells (BMSCs) isolated from long bone of new born rats were cultured,respectively,in TC199 medium (containing 10％ fetal bovine serum) with fluoride,aluminum and fluoride combined with aluminum.The osteoclasts were inoculated in 96-well culture plate and ivory slice,BMSCs in 6-well culture plate,and culture medium was changed after 2 hours incubation.The cells were divided into control group,fluoride group,aluminum group and fluoride combined with aluminum group; the doses of sodium fluoride were 0,1.0 × 10-4,0,1.0 × 10-4 mol/L and the doses of aluminum chloride were 0,0,1.0 × 10-5,1.0 × 10-5 mol/L,respectively.Tartrate-resistant acid phosphatase (TRAP) staining positive cells were counted under light microscope after TRAP staining on the 5th day and the pit formed in ivory slices were measured by histomorphometry after staining with toludine blue.The expression of osteoprotegerin(OPG) and receptor activator of nuclear factor kappa-B ligand (RANKL) was detected by real-time fluorescence quantitative PCR in BMSCs after 8 h treatment.Results ① Fluoride,aluminum and the interactive effects of fluoride and aluminum all had impact on the numbers of osteoclasts (F =7.15,6.56 and 7.98,respectively,all P ＜ 0.05).The numbers of osteoclasts in fluoride group,aluminum group and fluoride combined with aluminum group[(136.9 ± 22.99),(135.4 ± 23.5),(163.0 ± 24.4) per well] were higher than that in the control group[(92.5 ± 22.1) per well,all P ＜ 0.05].② Fluoride,aluminum and the interactive effects of fluoride and aluminum all had impact on the resorption pit area on ivory slices(F =10.47,12.64,14.29,respectively,all P ＜ 0.05).The resorption pit area on ivory slices in fluoride group,aluminum group and fluoride combined with aluminum group[(0.242 ± 0.031),(0.293 ± 0.026),(0.333 ± 0.016)mm2 per slice] was higher than that in the control group [(0.088 ± 0.030)mm2 per slice,all P ＜ 0.05].③Fluoride,aluminum and the interactive effects of fluoride and aluminum all had impact on the expression ratios of RANKL/OPG in BMSCs (F =8.15,15.38,23.59,respectively,all P ＜ 0.05).The expression ratios of RANKL/OPG in BMSCs in fluoride group,aluminum group and fluoride combined with aluminum group [(193.98 ± 137.93)％,(326.11 ± 176.78)％,(599.84 ± 275.82)％] were higher than that in the control group[(100.00 ± 56.02)％,all P ＜ 0.05].Conclusions Both fluoride and aluminum can cause increase in the number of osteoclasts in vitro and promote cell differentiation and bone resorption activity,which may be related to increased expression ratio of RANKL/OPG mRNA in BMSCs.The stimulating effects of fluoride on osteoclasts differentiation and bone resorption is enhanced by aluminum.