Allium cepa L. and Quercetin Inhibit RANKL/Porphyromonas gingivalis LPS-Induced Osteoclastogenesis by Downregulating NF-κB Signaling Pathway.
Objectives. We evaluated the in vitro modulatory effects of Allium cepa L. extract (AcE) and quercetin (Qt) on osteoclastogenesis under inflammatory conditions (LPS-induced). Methods. RAW 264.7 cells were differentiated with 30 ng/mL of RANKL, costimulated with PgLPS (1 µg/mL), and treated with AcE (50-1000 µg/mL) or Qt (1.25, 2.5, or 5 µM). Cell viability was determined by alamarBlue and protein assays. Nuclei morphology was analysed by DAPI staining. TRAP assays were performed as follows: p-nitrophenyl phosphate was used to determine the acid phosphatase activity of the osteoclasts and TRAP staining was used to evaluate the number and size of TRAP-positive multinucleated osteoclast cells. Von Kossa staining was used to measure osteoclast resorptive activity. Cytokine levels were measured on osteoclast precursor cell culture supernatants. Using western blot analysis, p-IκBα and IκBα degradation, inhibitor of NF-kappaB, were evaluated. Results. Both AcE and Qt did not affect cell viability and significantly reduced osteoclastogenesis compared to control. We observed lower production of IL-6 and IL-1α and an increased production of IL-3 and IL-4. AcE and Qt downregulated NF-κB pathway. Conclusion. AcE and Qt may be inhibitors of osteoclastogenesis under inflammatory conditions (LPS-induced) via attenuation of RANKL/PgLPS-induced NF-κB activation.
Departamento de Bio-Regulação, Instituto de Ciências da Saúde, Universidade Federal da Bahia, 40.110-100 Salvador, BA, Brazil ; Department of Clinical Sciences, University of Toronto, Restorative, Toronto, ON, Canada M5G 1G6.
Tatiane
T
Oliveira
Departamento de Bio-Regulação, Instituto de Ciências da Saúde, Universidade Federal da Bahia, 40.110-100 Salvador, BA, Brazil.
Camila A
CA
Figueiredo
Department of Clinical Sciences, University of Toronto, Restorative, Toronto, ON, Canada M5G 1G6.
Carlos
C
Brito
Department of Clinical Sciences, University of Toronto, Restorative, Toronto, ON, Canada M5G 1G6.
Alexander
A
Stavroullakis
Department of Clinical Sciences, University of Toronto, Restorative, Toronto, ON, Canada M5G 1G6.
Ana Carolina
AC
Ferreira
Department of Clinical Sciences, University of Toronto, Restorative, Toronto, ON, Canada M5G 1G6.
Getulio
G
Nogueira-Filho
Department of Clinical Sciences, University of Toronto, Restorative, Toronto, ON, Canada M5G 1G6.
Anuradha
A
Prakki