Fig 1: Chronic SF exacerbated the inflammatory response and promoted the formation of NETs in MI/RI mice. (A to C) Plasma concentrations of IL-1β, IL-6, and IL-18 in mice were measured by ELISA (n = 8 per group). (D to F) qRT-PCR assays were performed to determine mRNA levels of IL-1β, IL-6, and IL-18 in the hearts of MI/RI mice with SF (n = 6 per group). (G) Representative images of immunofluorescence staining of NETs in myocardial tissues from Sham, SF + Sham, MI/RI, and SF + MI/RI groups (green: MPO, red: citH3, blue: DAPI) (n = 6 per group). (H) Cell-free DNA (cfDNA) of each group (n = 6 per group). (I) The MPO–DNA complex relative levels were assessed in mice (n = 6 per group). Data are presented as mean ± SD. ###P < 0.001 versus Sham group; ***P < 0.001 versus SF + Sham group; $$P < 0.01 versus MI/RI group; $$$P < 0.001 versus MI/RI group. (J and K) Western blotting was used to analyze the expression of CXCR2 in NEs after treatment with EPI for 6 h (n = 6 per group). Data are presented as mean ± SD. ###P < 0.001 versus Control group. C + EPI, Control + EPI. (L) Schematic diagram of coculture of EPI-induced NEs and CMECs exposed to H/R. CMECs were treated with hypoxia for 12 h and reoxygenation for 24 h and then cocultured with NEs for 6 h. (M) Statistical analysis of the number of migrated NEs after coculture with H/R-induced CMECs (n = 6 independent experiments). (N and O) The cfDNA and MPO–DNA complex levels were assessed (n = 5 independent experiments). (P) After coculture, the ultrastructure of NEs was observed via the electron microscope. Data are presented as mean ± SD. ###P < 0.001 versus Control + NEs group; ***P < 0.001 versus H/R + NEs group. Scale bars, 50 μm (G) and 2.5 μm (P). NEs, neutrophils; EPI, epinephrine.