Background: Intestinal ischemia-reperfusion injury (IRI) is a severe complication of major surgeries and shock, leading to intestinal barrier dysfunction and systemic inflammation. Treatment options remain limited due to poorly defined mechanisms. Galectin-3, a β-galactoside-binding lectin that regulates inflammatory processes, has emerged as a potential modulator of tissue injury. This study aimed to investigate the role of Galectin-3 in IRI, focusing on janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) regulation to identify potential therapeutic targets.

Methods: After establishing a murine intestinal IRI model, mice were treated with varying doses of G3-C12, a Galectin-3 inhibitor. Intestinal injury, inflammation, tight junction protein (TJP) expression, apoptosis, and JAK2/STAT3 pathway activation were assessed using hematoxylin-eosin (H&E) staining, quantitative real-time polymerase chain reaction (qRT-PCR), Western blotting, terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay, and caspase activity assays. Additionally, the Caco-2 oxygen-glucose deprivation/reoxygenation (OGD/R) model was employed to validate the mechanism of Galectin-3, with pathway dependency evaluated using the JAK2 agonist C-A1.

Results: IRI induced significant intestinal structural disruption, increased pro-inflammatory cytokines (interleukin-6 [IL-6], tumor necrosis factor-α [TNF-α], p < 0.001), reduced anti-inflammatory interleukin-10 (IL-10) (p < 0.001), downregulated TJPs (p < 0.001), and elevated apoptosis (p < 0.001) in mice. These alterations coincided with upregulation of Galectin-3, phosphorylated JAK2 (p-JAK2), and phosphorylated STAT3 (p-STAT3) (p < 0.001). G3-C12 treatment markedly alleviated histopathological injury, reduced inflammation and apoptosis, dose-dependently restored TJP expression, and suppressed JAK2/STAT3 pathway activation (p < 0.01 or p < 0.001). In vitro OGD/R assays further demonstrated that G3-C12 improved cell viability, reduced lactate dehydrogenase (LDH) release, attenuated inflammation and apoptosis, and restored TJP levels, effects that were partially reversed by JAK2 activation with C-A1.

Conclusion: Galectin-3 is upregulated during IRI and promotes JAK2/STAT3 pathway activation, exacerbating inflammation and intestinal barrier dysfunction. Inhibition of Galectin-3 suppresses this aberrant signaling, mitigates intestinal injury, reduces apoptosis and inflammation, and restores TJPs expression and mucosal barrier integrity. These findings suggest Galectin-3 as a promising therapeutic target for IRI.