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Protection against titanium particle‐induced osteoclastogenesis by cyclooxygenase‐2 selective inhibitor
Author(s) -
Geng D. C.,
Zhu X. S.,
Mao H. Q.,
Meng B.,
Chen L.,
Yang H. L.,
Xu Y. Z.
Publication year - 2011
Publication title -
journal of biomedical materials research part a
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.849
H-Index - 150
eISSN - 1552-4965
pISSN - 1549-3296
DOI - 10.1002/jbm.a.33197
Subject(s) - rankl , osteoclast , cyclooxygenase , activator (genetics) , cathepsin k , materials science , acid phosphatase , prostaglandin e2 , cathepsin , tartrate resistant acid phosphatase , bone resorption , celecoxib , cancer research , microbiology and biotechnology , receptor , medicine , biochemistry , chemistry , biology , enzyme
Wear particle‐induced osteoclastogenesis is the most common cause of aseptic loosening in total joint arthroplasty. Although cyclooxygenase (COX)‐2, an inducible regulator of prostaglandin E2 (PGE2) synthesis, is known to be involved in osteoclast differentiation, its effect on osteoclastogenesis in response to wear particles remains unclear. In this study, we investigated the role of COX‐2 in the regulation of osteoclast differentiation in the osteoclast precursor cell line RAW264.7 stimulated with titanium (Ti) particles. The results showed COX‐2 expression in the early stages of RAW264.7 differentiation when stimulated with receptor activator of nuclear factor kappa B ligand (RANKL) and Ti particles. Blockade of COX‐2 by celecoxib, a COX‐2 selective inhibitor, effectively reduced the expression of PGE2 and inhibited differentiation of RAW264.7 cells into tartrate‐resistant acid phosphatase‐positive (TRAP + ) osteoclastic cells. Quantitative real‐time polymerase chain reaction revealed that celecoxib inhibited mRNA expression of RANK , cathepsin K ( CPK ), TRAP , and the nuclear factor of activated T cells c1 ( NFATc1 ) in RAW264.7 cells stimulated by Ti particles and RANKL. Moreover, exogenous PGE2 reversed the inhibitory effects of celecoxib. These results provide direct evidence that COX‐2 dependent PGE2 induced by RANKL and Ti particles is required for osteoclastogenesis and suggests that reduced production of PGE2 by inactivation of COX‐2 would provide a promising therapeutic target for the treatment of osteoclastogenesis induced by wear particles. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 2011.