Pyraclostrobin triggers pulmonary inflammation, oxidative stress, and fibrosis in mouse via Wnt/β-catenin signaling.

Pyraclostrobin (PYR), a broad-spectrum fungicide, is known for its aquatic toxicity, yet its mammalian toxicity remains poorly understood. This study utilized a network pharmacology approach to predict GSK3β as a potential target of PYR, further investigated PYR mechanism of action in lung injury, and validated the findings in a mouse model and a MLE-12 cell model. Mice were divided into control, low-dose (22.5 mg/kg/day), and high-dose (45 mg/kg/day) PYR groups (n = 8) and subjected to a 28-day chronic exposure. Pathological examination revealed alveolar wall thickening, collagen deposition, inflammatory infiltration, and impaired lung function. Bronchoalveolar lavage fluid showed increased protein and LDH levels, alongside elevated hydroxyproline, Collagen I, and α-SMA expression. PYR exposure induced mitochondrial dysfunction, indicated by reduced JC-1 aggregates in vivo and increased JC-1 monomers in MLE-12 cells, along with ROS overproduction. Pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) were upregulated, while anti-inflammatory factors (IL-10, TGF-β1) were suppressed. iNOS expression increased in both models. Oxidative stress was evident through decreased antioxidant enzyme activities (CAT, SOD, GSH-Px) and increased MDA. Cytoplasmic accumulation of Nrf2 was observed. Inhibition of the Wnt/β-catenin pathway with XAV-939 mitigated inflammation, oxidative stress, and fibrosis. These results indicate that the Wnt/β-catenin pathway integrates inflammatory and oxidative responses to promote PYR-induced pulmonary fibrosis, suggesting a potential therapeutic target for mitigating fungicide-related lung damage.