Figure 4 Oxidative stress and ferroptosis of DCD donor liver alleviated by BMMSCs. (A) IF of GPX4 and PTGS2 in hepatic tissues of different groups. GPX4 is shown in green, PTGS2 is shown in red, and the DAPI-stained nuclei are shown in blue. (B) Western blot of GPX4 and PTGS2 in hepatic tissues of different groups. The expression levels of GPX4 in the BP group were significantly higher than those in the P group (P=0.004) and SCS group (P<0.001). The expression levels of PTGS2 in the BP group were significantly lower than those in the P group (P=0.002) and SCS group (P<0.001). (C) MDA in hepatic tissues of different groups (P group vs SCS group, P<0.001; BP group vs SCS group, P<0.001; BP group vs P group, P=0.001). (D) GSH in hepatic tissues of different groups (P group vs SCS group, P 0.001; BP group vs SCS group, P<0.001; BP group vs P group, P=0.132). (E) The levels of Fe2+ release in different groups, which were significantly lower in the P and BP groups than those in the SCS group (P group vs SCS group, P<0.001; BP group vs SCS group, P<0.001; BP group vs P group, P=0.020). (F) The ultrastructure of hepatic tissues in different groups. The mitochondria of hepatocytes in SCS group showed severe edema and vacuolar degeneration, with irreversibly damaged mitochondria, partial mitochondrial necrosis and lysis (shown in white arrow), and disordered mitochondrial crest structure, which mostly disappeared. The mitochondria in the BP group and P group showed almost no swelling or vacuole degeneration, with intact mitochondrial crest structure and less irreversible mitochondrial damage. * P<0.05 vs the SCS group, # P<0.05 vs the P group. DCD – donation after circulatory death; SCS – static cold storage; P – NMP; BP – BMMSCs combined with NMP; NMP – normothermic machine perfusion; BMMSCs – bone marrow mesenchymal stem cells.