ABSTRACT
Objective To establish a rat model of coal-burning-borne fluorosis,and to observe the expression changes of bone morphogenetic protein-2 (BMP-2) and bone morphogenetic protein-3 (BMP-3) in the serum of rat treated with different dose of fluoride and different treatment duration.Methods A total of 120 clean grade SD rats(body mass between 80 to 120 g) weaned for 4 weeks were randomly assigned into four groups,which were control,low-dose fluorid,medium-dose fluorid and high-dose fluorid groups,respectively,and 30 rats in each group (female 15,male 15).All of the rats were fed with coal drying corn from fluorosis area.Ten rats were killed by femoral artery bleeding 30 d,90 d and 180 d after exposed to fluoride,respectively.Serum BMP-2 and BMP-3 level was tested by enzyme-linked immunosorbent assay (ELISA).Results ①Results of BMP-2:after exposed to fluoride for 90 d and 180 d,the differences of serum BMP-2 level between groups were statistically significant(F=385.08,173.98,all P ＜ 0.01).In low-dose fluorid,medium-dose fluorid and high-dose fluorid groups,the expression of serum BMP-2 at 90 d[(18.80 ± 0.43),(22.22 ± 0.85),(25.14 ± 0.69)μg/L] and 180 d[(7.98 ± 0.68),(8.97 ± 0.78),(15.04 ± 0.89)μg/L] was higher than that of control group[(12.54 ± 1.29),(7.53 ± 0.97)μg/L,all P ＜ 0.05],and the level of BMP-2 increased with increasing dose of fluoride (all P ＜ 0.05).Within each group,the difference of serum BMP-2 was statistically significant(F =55.42,511.58,686.35,671.64,all P ＜ 0.01).The expression of BMP-2 in each group at 90 d [(12.54 ± 1.29),(18.80 ± 0.43),(22.22 ± 0.85),(25.14 ± 0.69)μg/L] was higher than that at 30 d[(11.75 ± 1.15),(11.42 ± 1.07),(11.38 ± 0.92),(11.15 ±1.03)μg/L,all P ＜ 0.05].The expression of BMP-2 in each group at 180 d[(7.53 ± 0.97),(7.98 ± 0.68),(8.97 ± 0.78),(15.04 ± 0.89) μg/L] was lower than that at 90 d.②Results of BMP-3:the difference between groups was not statistically significant at every experimental stage(F =0.7215,1.2951,0.0964,all P ＞ 0.05).Conclusions Longer excessive fluoride intake stimulates the expression of BMP-2 in rats,but with prolonged fluoride intake,the stimulation becomes weak.The effect of fluoride on BMP-3 is not as sensitive as that on BMP-2.