Effect of quercetin on osteoblast dysfunction in osteoporotic rats by regulating Nrf2/SLC7A11/GPX4 pathway-mediated...

This study aims to explore the effect of quercetin on osteoblast dysfunction in osteoporotic rats and to clarify its role in regulating ferroptosis mediated by the Nrf2/SLC7A11/GPX4 signaling pathway, in order to provide new experimental evidence and potential therapeutic targets for the prevention and treatment of osteoporosis. Female SD rats were randomly divided into a control group, model group, and quercetin low-, medium- and high-dose groups. The osteoporosis model was established by bilateral ovariectomy. Micro-CT was used to detect femoral microstructural parameters (BV/TV, Tb.Th, Tb.N, and Tb.Sp), and RT-qPCR was used to detect the mRNA expression levels of osteogenic-related genes ALP, BMP2, OPN, RUNX2, FN, TNMD, COL-I, and COL-III in femoral tissue. ELISA and kits were used to detect oxidative stress indicators SOD, GSH, CAT, and MDA, and iron ion content in femoral tissue homogenate. Western blot was used to detect the expression levels of Nrf2, SLC7A11, and GPX4 proteins in femoral tissue. In vitro experiments were conducted using MC3T3-E1 cells, with third-passage cells specifically utilized to induce osteogenic mineralization. Cell viability was assessed using the CCK-8 assay, while cell death rates were determined via Annexin V-FITC/PI double-staining flow cytometry. Intracellular iron ion content was evaluated through biochemical assays, and the mRNA expression levels of ALP and RUNX2 were detected using RT-qPCR. Quercetin alleviated osteoporosis symptoms in rats by enhancing bone microstructure and stimulating osteogenic differentiation. These improvements were characterized by significant increases in BV/TV, Tb.Th, and BMD alongside a reduction in Tb.Sp. Furthermore, Quercetin promoted bone formation by upregulating the expression of key osteogenic markers, including ALP, BMP2, OPN, RUNX2, FN, TNMD, COL-I, and COL-III. Quercetin could suppress inflammation. In addition, quercetin also inhibited ferroptosis by reducing oxidative stress (increasing SOD and CAT activities and reducing MDA content) and iron overload (reducing iron ion content) and activating the Nrf2/SLC7A11/GPX4 signaling pathway, thereby further protecting bone tissue from damage. In vitro experiments demonstrate that quercetin effectively inhibits Erastin-induced ferroptosis in MC3T3-E1 cells, attenuates cellular damage, and restores their impaired osteogenic differentiation capacity. Quercetin can improve bone microarchitecture and osteoblast dysfunction in osteoporotic rats, which involves reducing oxidative stress and iron overload in bone tissue and activating the Nrf2/SLC7A11/GPX4 signaling pathway, thereby inhibiting the occurrence of ferroptosis.