Neutrophil Extracellular Traps Mediate the Detrimental Effects of Jugular Venous Reflux on Cerebral Ischemia–Reperfusion Injury

Background: Jugular venous reflux (JVR) impairs cerebral venous drainage and may aggravate ischemic brain injury; however, its underlying mechanisms are unclear. Neutrophil extracellular traps (NETs) are key mediators of inflammatory damage in stroke. This study investigated whether JVR exacerbates cerebral ischemia-reperfusion injury by promoting NET formation and evaluated the therapeutic potential of DNase I. Methods: Rats were allocated into Sham, BJVL alone, UCAO alone, and BJVL+UCAO groups. Chronic JVR was induced by bilateral jugular vein ligation (BJVL). One week later, transient middle cerebral artery occlusion (UCAO) was performed. Neurological deficits (Longa score), infarct volume (TTC staining), NET formation (H3Cit, MPO, CD11b), and plasma cytokines (IL-1β, IL-6, IL-10, TNF-α) were assessed. DNase I was administered post-reperfusion. In vitro, PMA-induced NETs were co-cultured with hippocampal neurons to assess cytotoxicity. Results: BJVL alone did not cause infarction but worsened UCAO-induced deficits, infarct volume, and weight loss. BJVL+UCAO increased MPO, CD11b, H3Cit, and pro-inflammatory cytokines. DNase I reduced infarct size, H3Cit, and cytokines without affecting neutrophil recruitment. In vitro, PMA-induced NETs decreased neuronal viability and increased apoptosis, effects reversed by DNase I. Conclusions: JVR aggravates cerebral ischemia-reperfusion injury by enhancing neutrophil infiltration and NET formation. DNase I mitigates injury by degrading NETs, highlighting its therapeutic potential in stroke with venous impairment.