Electroacupuncture alleviates endometriosis by suppressing ferroptosis in murine ectopic and eutopic endometria via the Nrf2 pathway

RESEARCH QUESTION: Does peritoneal iron overload drive fibrosis in endometriosis through Nrf2 pathway dysfunction and the resulting ferroptosis, and can electroacupuncture intervene in this process? DESIGN: An endometriosis mouse model was established by intraperitoneal injection of syngeneic uterine fragments combined with periodic injection of whole blood, and subjected to electroacupuncture intervention. Fibrosis, ferroptosis-related markers, Nrf2/Keap1 pathway activity, the peritoneal microenvironment and systemic pathological indicators were systematically assessed using histological staining, molecular biology techniques and biochemical analyses. RESULTS: Eutopic uterus and ectopic lesions in mice with endometriosis had significant fibrosis (P < 0.01) accompanied by pronounced ferroptosis (P < 0.01). Mechanistically, the Nrf2 pathway was functionally inactivated in these tissues, with impaired nuclear translocation (P < 0.01). Notably, in the eutopic uterus, this inhibition occurred independently of its classical regulatory protein Keap1, suggesting alternative regulatory mechanisms for Nrf2. Electroacupuncture treatment effectively suppressed lesion growth (P < 0.05) alleviated fibrosis (P < 0.01) and ferroptosis (P < 0.01), and also specifically reversed the impairment of Nrf2 nuclear translocation (P < 0.01) and improved systemic inflammation and endocrine disturbances. CONCLUSIONS: To our knowledge, this study is the first to systematically demonstrate the pivotal role of the 'Nrf2 pathway inactivation‒ferroptosis‒fibrosis' axis in endometriosis, particularly in the eutopic uterus. Our findings provide a novel paradigm for understanding the pathological mechanisms of endometriosis and confirms that electroacupuncture exerts therapeutic effects by targeting this pathway, offering a solid experimental foundation for its clinical application.