Theaflavin-3,3-Digallate Inhibits Erastin-Induced Chondrocytes Ferroptosis via the Nrf2/GPX4 Signaling Pathway in Osteoarthritis

Figure 4

TF3 activates the Keap1/Nrf2 signaling and the MEK1/2/ERK1/2 signaling pathways in chondrocytes stimulated with erastin. (a) The levels of Nrf2, Keap1, p-MEK1/2, MEK1/2, p-ERK1/2, and ERK1/2 in chondrocytes after stimulation were examined by western blotting; representative bands are shown. (b) Quantitative analysis for the expression of Nrf2, Keap-1, p-MEK1/2, and p-ERK1/2 in chondrocytes. (c) The nucleus and cytoplasm expression levels of Nrf2 in chondrocytes were determined by western blotting; representative bands are shown. (d) Quantitative analysis for the nucleus and cytoplasm expression levels of Nrf2. The human lamin B and β-actin antibodies were used as the internal controls for nucleus and cytoplasm protein loading, respectively. The data are presented as the of three independent experiments, and statistical significance was determined by one-way ANOVA. , . NC: chondrocytes were cultured in DMEM-F12 for 24 hrs. Erastin: chondrocytes were treated with 5 μM erastin for 24 hrs. Erastin+15TF3/Erastin+30TF3: chondrocytes were pretreated with different concentrations of TF3 (15 μM, 30 μM) and then incubated with erastin. Nrf2: nuclear factor erythroid 2-related factor 2.

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