Suppressing PAD-4 protein significantly reduced NETs release. (A) Immunofluorescence (scale bars, 20 μm) analysed PAD-4, MPO, NE, cTNT and CitH3 levels in I/R + CI-am and I/R + saline groups. (B) Fluorescence intensity of CD11c, cTNT, CitH3, MPO and NE was semi-quantitatively analysed (n = 6). (C–E) Western blot quantified PAD-4, MPO, NE, cTNT and CitH3 levels (n = 6). ‘ns’ denotes no significant difference. ***P < 0.001. Data are expressed as mean (SD). CI-am: CI-amidine; CitH3: citrullinated histone H3; cTNT: cardiac troponin T; I/R: ischaemia–reperfusion; MPO: myeloperoxidase; NE: neutrophil elastase; NETs: neutrophil extracellular traps; PAD-4: peptidylarginine deiminase 4; SD: standard deviation.