In RA-based fibroblasts, 2 μM DRF decreased GPX4 to 65 ± 19% after 3 h, to 59 ± 21% after 6 h, and to 48 ± 21% after 24 h (Fig. 6g) and in OA-based fibroblasts to 55 ± 21% after 3 h, to 40 ± 11% after 6 h, and to 43 ± 12% after 24 h (Fig. 6n). This evidence concerns the gene GPX4 and rheumatoid arthritis.