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.
ABSTRACT
Objective To investigate the effect of fluoride on the expression of a subunit of calcium/calmodulin-dependent protein kinase- Ⅱ (α-CaMK Ⅱ ) at both mRNA and protein levels in human neuroblastoma cells were cultured in DMEM with final concentrations of NaF 0(control) ,0.05,0.50,2.00,5.00 mmol/L, respectively, for 48 hours. Then quantitative RT-PCR and Western blot were performed to detect the expression level of α-CaMK Ⅱ P1 (postnatal day 1) pups together with their mothers were randomly divided into three groups. Lactating rats were given drinking water containing NaF at concentrations 0(control) ,2,3 mmol/L. And pups were exposed to NaF through milk. In each group, 8 pups were sacrificed on day 14 after birth. In post-weaning period, another 8 pups in each group were given drinking water with the same dose of fluoride as their mother's 21 day after birth. After then, these pups were killed on day 28, and hippocampus was dissected immediately and Western blot was conducted mRNA and protein levels were decreased. When NaF concentrations were 0,0.05,0.50,2.00,5.00 mmol/L, the mRNA relative ratios of α-CaMKⅡ in SY5Y cells were 1.00 ± 0.00,0.77 ± 0.18,0.40 ± 0.11,0.22 ± 0.06 and 0.15 ± 0.03, and protein levels of α-CaMK Ⅱ were 100.00 ± 0.00,76.17 ± 2.08,59.16 ± 2.12,48.52 ± 2.71 and 43.51 ± 2.57, any mmol/L group, hippocampus α-CaMK Ⅱ protein levels on day 14 and 28(75.02 ± 2.88,73.83 ± 3.88 and 81.00 ± 2.54,45.70 ± 2.34) were significantly lower than that of control groups(100.00 ± 0.00,100.00 ± 0.00, all P < 0.01). In 3 mmol/L group, hippocampus α-CaMKⅡ protein level on day 28 was lower than that of 2 mmol/L group (P < 0.01). Conclusion Fluoride can decrease mRNA and protein levels of α-CaMK Ⅱ in nerve cells and hippocampus, which may be one of the mechanisms of learning and memory impairment by fluorosis.