Celecoxib treatment dampens LPS‐induced periapical bone resorption in a mouse model

Aim To evaluate the efficacy of selective and nonselective inhibitors of cyclooxygenase‐2 enzymes in the treatment of experimental apical periodontitis induced by bacterial lipopolysaccharide (LPS) in vivo in a mouse model. Methodology Thirty‐six C57BL/6 mice were used. After access cavity preparation, a solution containing E. coli LPS (1.0 µg µL−1) was inoculated into the root canals of the mandibular and maxillary right first molars (n = 72) After 30 days, apical periodontitis was established and the animals were systemically treated with celecoxib, a selective COX‐2 inhibitor (15 mg kg−1), or indomethacin, a nonselective COX‐2 inhibitor (5 mg kg−1), for 7 and 14 days. Blocks containing teeth and bone were removed for histopathological and histometric analyses (haematoxylin and eosin), evaluation of osteoclasts numbers (tartrate‐resistant acid phosphatase enzyme – TRAP) and immunohistochemistry for RANK, RANKL and OPG. Gene expression was performed using reverse transcription and real‐time polymerase chain reaction (qRT‐PCR) for RANK, RANKL, OPG, TRAP, MMP‐9, cathepsin K and calcitonin receptor. Histopathological, histometric, TRAP, immunohistochemistry and qRT‐PCR data were evaluated using Kruskal–Wallis followed by Dunn’s test (α = 0.05). Results Systemic administration of celecoxib for 7 and 14 days prevented periapical bone resorption (P