Atraric acid alleviates chronic intermittent hypoxia-induced renal fibrosis by inhibiting oxidative stress and ferroptosis in obstructive sleep apnea mice through the Nrf2/GPX4 pathway

Chronic intermittent hypoxia (CIH) caused by obstructive sleep apnea (OSA) exacerbates renal dysfunction, fibrosis, and chronic kidney disease (CKD) progression. This study investigates the renoprotective effects and mechanisms of atraric acid (AA), a natural compound from oakmoss with anti-inflammatory and antioxidant properties, against CIH-induced renal injury. A CIH mouse model was established, with groups including control, CIH, and CIH mice treated with AA (5, 10, 20 mg/kg). Mice underwent daily 8-h hypoxia exposure for 4 weeks. Renal pathology was assessed via HE and Masson staining, while fibrosis markers (α-SMA, collagen I, TGF-β1), oxidative stress (DHE staining, MDA levels), ferroptosis (iron content), and Nrf2/GPX4 pathway proteins were analyzed using biochemical assays and Western blotting. Results showed that AA treatment dose-dependently alleviated CIH-induced renal injury and fibrosis, reducing the expression of fibrotic proteins. AA suppressed ROS accumulation and lipid peroxidation while mitigating iron overload. Mechanistically, AA activated the Nrf2/Keap1 pathway, upregulating antioxidant proteins GPX4 and SLC7A11, thereby inhibiting oxidative stress and ferroptosis. These findings provide the first evidence that AA ameliorates CIH-related renal damage by targeting the Nrf2/GPX4 axis, offering a novel therapeutic strategy for CKD associated with OSA. The study highlights AA's potential in attenuating hypoxia-driven renal fibrosis through dual modulation of oxidative stress and ferroptosis pathways.