Quercetin Aglycone Up-Regulates Antioxidant Response Genes And Proteins In Osteoblast-Like Fetal Rat Calvarial Cells

Quercetin (QRC), a flavonol found in fruits and vegetables, has been shown to up‐regulate antioxidant response genes and proteins in a variety of cell types, but little is known about the effects of QRC on these genes and proteins in osteoblasts. The purpose of this study was to determine the extent that QRC alters expression of antioxidant genes and proteins in primary cultures of fetal rat calvarial cells, a well‐described model of osteoblast differentiation. Cells were treated up to 48 h starting at confluence with 0 or 20 μM QRC aglycone. Antioxidant gene and protein expression were analyzed using real‐time quantitative PCR and Western blotting, respectively. Quercetin significantly up‐regulated heme oxygenase 1 (HO‐1), catalase, and gamma‐glutamate‐cysteine ligase catalytic subunit (GCLC) (p < 0.05), but did not up‐regulate peroxiredoxins 3 and 5, and NADPH:quinone oxidoreductase (p >; 0.05). Protein expression was generally congruent with gene expression, with HO‐1 being the most markedly up‐regulated in response to 20 μM QRC. These data suggest that QRC up‐regulates some genes and proteins associated with the antioxidant response in osteoblasts. Since evidence suggests that oxidative stress may contribute to osteoporosis, QRC may have protective effects on bone health. Grant Funding Source : USDA Agricultural Research Services