Objective: To characterize the expression of lipopolysaccharide (LPS) receptors-CD14 and TLR4 in rat peri-radicular tissue and to investigate the signal transduction pathway of LPS and its receptors in periapical periodontitis.
Methods: After establishment of a model of rat molar LPS-induced apical periodontitis, CD14 and TLR4 expression in healthy and inflammatory periapical tissue were determined by immunohistochemistry.
Results: CD14 and TLR4 were not detected in healthy periapical tissue but strongly positive in inflammatory periapical tissue. Positive cells were mostly monocytes/macrophages.
Conclusions: CD14 and TLR4 may play an important role in the pathogenesis of periapical periodontitis, probably via immune cells such as monocytes/macrophages and neutrophils.