Objective To observe the expression of dickkopf-1 (DKK-1) in serum of fluoride bone injury (FBI) patients and analyze the relationship between fluoride bone injury occurrence and DKK-1 expression levels.
Methods General information of fluoride exposed population was collected by a self-designed questionnaire. Venous blood and random midstream urine were sampled from the subjects to detect their serum and urinary fluoride concentrations and serum DKK-1 protein levels followed by informed consent. Dental fluorosis inspection and orthophoric forearm radiography were also performed. Differences in DKK-1 expressions were analyzed among participants grouped by serum fluoride level, dental fluorosis, and skeleton fluorosis diagnostic criteria.
Results The concentrations of DKK-1 in the low, middle, and high fluoride burden groups were (9.60& #177; 0.52), (17.74& #177;0.80), and (14.31& #177;1.20) μg/L, respectively, and the difference was statistically significant among the three fluoride burden groups (P<0.05). There was no significant difference in DKK-1 expressions between the dental fluorosis group and the no dental fluorosis group (P>0.05). The levels of DKK-1 in the no, mild, moderate, and heavy FBI groups were (19.16& #177;0.76), (15.86& #177;1.35), (13.27& #177;0.45), and (12.42& #177;0.04) μg/L, respectively, with statistical differences (P<0.05).
Conclusion The level of DKK-1 is significantly decreased in patients with FBI. These results also indicate that long-term exposure to high level of fluoride can downregulate DKK-1 expression and might induce occurrence of FBI.
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