Enterococcus Faecalis Effect On Expression Of NFATc1and Cathepsin K In Experimental Rat Periapical Periodontitis

Objective: To study Enterococcus faecalis effect on the expression of Nuclearfactor of activated T-cells cytoplasmic1(NFATc1) and Cathepsin Kin the process ofrat periapical periodontitis.Methods:24male Sprague-Dawley rats were randomly divided into two groups:A group and B group) A group,pulp cavity of the mandibular right first molars wereleft open to oral environment, B group, pulp cavity of the mandibular right firstmolars were enclosed with Enterococcus faecalis. the mandibular left first molarswere used for control. Three rats of each group were sacrificed on1week,2week,3week,4week. Multiple scans were taken by Micro-CT.The mandibular that containedthe first molar were obtained for the frozen sections,which performed for HEstaining,Anti-human NFATc1and anti-human Cathepsin K were usd forimmunohistochemical staining, and anti-tartaric acid phosphatase (TRAP) stainingwas taken for the expression of osteoclasts.Results:1．On1week,Micro-CT showed that periodontal ligament of the mandibular rightfirst molar become widen;on2week, the apical lesions were readily detectable and asignificant apical lesions and bone resorptions on4week.2．From1week to2week, a large number of inflammatory cell infiltration in theright mandibular first molar and apical area of A group and B group; From3week to4week,two groups have a large number of lymphocytes,the control was no change.3．From1week to4week, the number of NFATc1-positive cells increased,peaking on day28. The number of CathepsinK positive cells increased substantiallyfrom1week to2week and then gradually decreased from2week to4week.4．TRAP positive cells increased substantially from1week to2week and then gradually decreased from2week to4week.Conclusion:1.The expression of NFATc1and Cathepsin K in periapical periodontitis，whichimply that possibly involved in the inflammatory response and bone resorption.2. Enterococcus faecalis up-regulated the expression of NFATc1and CathepsinK in periapical periodontitis a, it facilitated the differentiation of osteoclast, acceleratethe process of periapical periodontitis bone resorption.