Hydroxysafflor yellow A attenuates TBHP-induced lipid peroxidation and calcification-related changes in human endplate chondrocytes: involvement of SLC7A11/GPX4 signaling.

Intervertebral disc degeneration (IDD) is a chronic degenerative disorder, with oxidative stress being one of the primary driving mechanisms of IDD. Hydroxysafflor yellow A (HSYA), a major active component of safflower, exhibits potent antioxidant, anti-inflammatory, and anti-apoptotic properties. However, its role in IDD remains unclear. To explore the mechanism underlying HSYA's protection against tert-butyl hydroperoxide (TBHP)-induced oxidative stress in chondrocytes. Chondrocytes were treated with TBHP (100 µM) to establish an oxidative stress model, followed by administration of HSYA (5, 10, and 20 µM). Cell viability and apoptosis were assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry, respectively. Lipid peroxidation levels were evaluated by immunofluorescence. The protein expression levels of solute carrier family 7 member 11 (SLC7A11), glutathione peroxidase 4 (GPX4), SRY-box transcription factor 9 (SOX9), type II collagen (COL2), matrix metalloproteinase 3 (MMP-3), type X collagen (COL10), and runt-related transcription factor 2 (RUNX2) were analyzed by western blot analysis. mRNA expression of SLC7A11, GPX4, COL10, and RUNX2 was determined using reverse transcription quantitative polymerase chain reaction (RT-qPCR). Calcium deposition in endplate chondrocytes was examined by Alizarin Red staining. Compared with the control group, treatment with TBHP markedly reduced chondrocyte viability, promoted ferroptosis, and significantly elevated intracellular lipid peroxidation levels. Furthermore, TBHP exposure triggered a prominent increase in chondrocyte apoptosis, cartilage endplate (CEP) degeneration, and chondrocyte calcification. Notably, all these findings were dose-dependently reversed by HSYA intervention. However, SLC7A11 knockdown abolished the protective effects of HSYA against TBHP-induced chondrocyte damage. In summary, our findings indicate that HSYA protects chondrocytes from TBHP-induced oxidative stress, ferroptosis, apoptosis, and calcification, and alleviates CEP degeneration, at least partly associated with SLC7A11/GPX4-related redox regulation, providing in vitro experimental evidence for exploring its value in IDD-related research.