Objective To observe the expression of bone morphogenetic protein-2 (BMP-2) and bone morphogenetic protein-3 (BMP-3) in the serum of children in coal-burning endemic fluorosis areas.
Methods The study enrolled 366 children from two primary schools of Tujing Village (endemic fluorosis area) and 120 children from one primary school of Huaga Village (control area), Shuicheng County, Liupanshui City, Guizhou Province. All children were 8-14 years old and received a survey on dental fluorosis and urinary fluoride. Based upon informed consent, 115 children in the endemic fluorosis area categorized by dental fluorosis grade and 57 children in the control area were selected for serum sample collection to determine concentrations of serum BMP-2 and BMP-3.
Results The incidence rate of dental fluorosis in the endemic fluorosis area was 61.5% and dental fluorosis was not found in the control children (χ2=265.130, P < 0.05). The children's average urinary fluoride concentration in the fluorosis areamedian (P25, P75) 0.77(0.536, 1.136)mg/L was higher (Z=-7.716, P < 0.05) than that in the control area0.49(0.370, 0.660)mg/L (Z=-7.716, P < 0.05). The average concentrationsmedian (P25, P75) of serum BMP-2 and BMP-3 of children in the endemic fluorosis area16.40(13.51, 27.08)ng/L and 155.39(132.57, 177.95)ng/L, respectively were lower than those in the control area18.73(14.89, 25.84)ng/L and 163.67(149.18, 190.74)ng/L, respectively (ZBMP-2=-2.023, PBMP-2< 0.05; ZBMP-3=-2.736, PBMP-3< 0.01, respectively). The average concentration of serum BMP-3 in the children of 13-14 age group in the endemic fluorosis area139.52(122.53, 159.07)ng/L was lower than that of the children at same age group in the control area174.05(154.15, 195.03)ng/L (Z=-2.967, P < 0.01). No differences were found in serum levels of BMP-3 and BMP-2 among the children in the endemic fluorosis area categorized by dental fluorosis degree (χ2BMP-2=4.680, PBMP-2=0.322; χ2BMP-3=2.649, PBMP-3=0.618, respectively) and urinary fluoride (χ2BMP-2=1.292, PBMP-2=0.731; χ2BMP-3=1.440, PBMP-3=0.696, respectively).
Conclusion Low concentrations of serum BMP-2 and BMP-3 are measured in the children in fluorine disease areas in Liupanshui City of Guizhou Province, indicating that fluoride may impact the expression of BMP-2 and BMP-3 in serum.
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