Fig. 2

Ferroptosis progressively increased in human NP tissues as IVDD advanced. A Representative MRI images of human NP tissues with different degrees of degeneration. Four discs samples with mild degeneration and four with severe degeneration from eight patients were collected. B H/E and Alcian blue staining of human NP samples in NP tissues from Pfirrmann grades II and V. Scale bar: 25 μm. C, D Representative western blot images of ferroptosis-associated proteins GPX4, FTH1, and SLC7A11, and ECM degradation-associated proteins MMP3 and ADAMTS5 in NP tissues from Mild- and Severe- IVDD groups. The relative band densities were quantified. E, F IHC staining of GPX4 in human nucleus pulposus sections. Scale bar: 25 μm. Quantitative analysis was shown as percentage of GPX4⁺ cell in NP tissues. G The relative mRNA levels of GPX4 in NP tissues from Mild- and Severe-IVDD groups. H Relative GSH levels in NP tissues from Mild- and Severe-IVDD groups. I Quantification of MDA contents in NP tissues from Mild- and Severe-IVDD groups. (*P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001)