Allium cepa L. and Quercetin Inhibit RANKLPorphyromonas gingivalis LPS-Induced Osteoclastogenesis by Downregulating NF-κB Signaling Pathway

الملخص EN

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.