Improvement Of The Method Of Establishment Animal Dental Fluorosis Model Caused By Coal-burning And The Effect Of Excessive Fluoride On The Expression Of KLK4 And DPPI Protein In The Rat Ameloblast

Dental fluorosis is widely popular in the world. However,the mechanism of how excessive fluoride exposure,especially from coal burning,causing fluorosis remains uncertain. High fluoride air may take an important part in the processes. The modle should be more credible that feeding with corn rich in fluoride in the high fluoride air room established basis on the living habit of epidemic area by coal burning with clay rich of fluoride. Some scientists observed crystal structure of fluorosed dental enamel normal but the gap between the enamel rod widen by SEM and estimated that the maturation stage rather than the secretory stage was affected. The structure of fluorosed dental enamel is likely with the Hypomaturation enamel defects in kallikrein 4 (klk4) knockout. Dipeptidyl peptidaseⅠ(DPPI) would activate KLK4 during enamel formation.Thus, we establish animal dental fluorosis model caused by coal burning and the research of KLK4 and DPPI protein expression in the rat ameloblast to explore partial molecule mechanism of dental fluorosis.Objective:To establish more credible animal dental fluorosis model caused by fluoride coal burnin and study the influence of fluoride on the expression of KLK4 and DPPI in the rat ameloblast.To explore the mechanism of dental fluorosis caused by coal burning.Methods:High fluoride air model was established basis on the living habit of epidemic area by coal burning with clay rich of fluoride. Feeding rats with corn dried by coal burning at different percentage.Thirty-six SD rats were randomly divided into 6 groups:the high fluoride air and feed F 40mg/kg group(H),the high fluoride air and feed F 25mg/kg group(M), the high fluoride air and feed fluoride 10mg/kg group(L), the high fluoride air and common food group(A), the positive control group (P) and the control group(C). Measure rats weight,tooth length,concentrations of fluoride in the urine and the plasma once 28 days. Digital camera record dental fluorosis progresses.All rats were killed at the end of 16th week,then observed the ameloblast morphology by hematoxylin-eosin(HE) and the surface of enamel SEM. The expression of KLK4 and DPPI in the ameloblast were detected by immunohistochemistry.Result:The fluoride concentration of air was 28.5±5.3ug/m3in the experimental group room at the burning time,and 4.1±.2 ug/m3 at other time.The surface of incisors were recorded by camera. A succession of white and pigmented bands were observed in the fluorotic rat incisors of the group H,P and M. There were statistical differences of concentrations of fluoride in the urine and the plasma and tooth length between every experimental group(P<0.05) except the group A and the group C(P>0.05),the experimental group higher than the group C.Separately compared with the male and the female of the group C,the mean of rats weight descended in the experimental group(P<0.05). It was shown no notable difference of the ameloblast in the groups by HE staining. Observed crystal structure normal but the gap between the enamel rod widen at the white surface of fluorosis incisors by SEM. Immunohistochemistry showed expression of KLK4 and DPPI increased in the ameloblasts at the maturation stages. Compared with the group C,the expression of KLK4 and DPPI significantly descended in the experiment groups except group A (P<0.05)Conclusion:It was successful to establish the high fluoride air model that would have effect on the rat growth. On these conditions, more credible animal dental fluorosis model could been established caused by fluoride in coal. The mechanism of dental fluorosis would be that overdose interferes with expression of the protein and enmal matrix mineralization.