Cyclooxygenase-2 inhibition selectively attenuates bone morphogenetic protein-6 synthesis and bone formation during guided tissue regeneration in a rat model

Damrongsri, Damrong; Geva, Sarah; Salvi, Giovanni E; Williams, Ray C; Limwongse, Visaka; Offenbacher, Steven (2006). Cyclooxygenase-2 inhibition selectively attenuates bone morphogenetic protein-6 synthesis and bone formation during guided tissue regeneration in a rat model. Clinical oral implants research, 17(1), pp. 38-47. Oxford: Wiley-Blackwell 10.1111/j.1600-0501.2005.01187.x

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OBJECTIVES: Bone formation during guided tissue regeneration is a tightly regulated process involving cells, extracellular matrix and growth factors. The aims of this study were (i) to examine the expression of cyclooxygenase-2 (COX-2) during bone regeneration and (ii) the effects of selective COX-2 inhibition on osseous regeneration and growth factor expression in the rodent femur model. MATERIAL AND METHODS: A standardized transcortical defect of 5 x 1.5 mm was prepared in the femur of 12 male rats and a closed half-cylindrical titanium chamber was placed over the defect. The expression of COX-2 and of platelet-derived growth factor-B (PDGF-B), bone morphogenetic protein-6 (BMP-6) and insulin-like growth factor-I/II (IGF-I/II) was analyzed at Days 3, 7, 21 and 28 semiquantitatively by reverse transcriptase-polymerase chain reaction and immunohistochemistry. The effects of COX-2 inhibition by intraperitoneal injection of NS-398 (3 mg/kg/day) were analyzed in five additional animals sacrificed at Day 14. RESULTS: Histomorphometry revealed that new bone formation occurred in the cortical defect area as well as in the supracortical region, i.e. region within the chamber by Day 7 and increased through Day 28. Immunohistochemical evidence of COX-2 and PDGF-B levels were observed early (i.e. Day 3) and decreased rapidly by Day 7. BMP-6 expression was maximal at Day 3 and slowly declined by Day 28. In contrast, IGF-I/II expression gradually increased during the 28-day period. Systemic administration NS-398 caused a statistically significant reduction (P<0.05) in new bone formation (25-30%) and was associated with a statistically significant reduction in BMP-6 protein and mRNA expression (50% and 65% at P<0.05 and P<0.01, respectively). PDGF-B mRNA or protein expression was not affected by NS-398 treatment. CONCLUSION: COX-2 inhibition resulted in reduced BMP-6 expression and impaired osseous regeneration suggesting an important role for COX-2-induced signaling in BMP synthesis and new bone formation.

Item Type:	Journal Article (Original Article)
Division/Institute:	04 Faculty of Medicine > School of Dental Medicine > Department of Periodontology
UniBE Contributor:	Salvi, Giovanni Edoardo
Subjects:	600 Technology > 610 Medicine & health
ISSN:	0905-7161
Publisher:	Wiley-Blackwell
Language:	English
Submitter:	Eveline Carmen Schuler
Date Deposited:	04 Oct 2013 14:52
Last Modified:	05 Dec 2022 14:16
Publisher DOI:	10.1111/j.1600-0501.2005.01187.x
PubMed ID:	16441783
Web of Science ID:	000234854400005
URI:	https://boris.unibe.ch/id/eprint/21892 (FactScience: 19557)