Proanthocyanidins inhibit the inflammation response of dry eye by regulating IRAK4/JAK1/STAT1 signaling pathway

The persistent inflammation response of the ocular surface is a problem that dry eye (DE) has been difficult to solve. The purpose of this study was to explore the therapeutic effect and potential mechanism of proanthocyanidins (PA) on DE in vitro and in vivo. The downstream targets of PA were predicted and analyzed by bioinformatics. In the experimental study, the expression of IRAK4, JAK1 and STAT1 was detected by Western blot, the cell viability was detected by CCK8, and the expression of MMP9 and TNF-α in cells and mice corneal epithelium was detected by immunofluorescence. Elisa was used to detect the concentration of MMP9 and TNF-α in cell supernatant. The corneal fluorescence staining and tear secretion of mice were detected by fluorescein sodium and phenol red cotton thread. Bioinformatic analysis identified IRAK4, STAT1, and PTGS1 as key PA-associated targets enriched in inflammation-related pathways. Hyperosmotic stress increased IRAK4 expression while suppressing JAK1/STAT1 phosphorylation in HCE-T cells. PA significantly reduced IRAK4 levels, restored p-JAK1 and p-STAT1 expression, and suppressed MMP9 and TNF-α production in vitro and vivo. PA also enhanced HCE-T proliferation and migration under hyperosmotic conditions. In DE mice, topical PA markedly improved tear secretion, reduced corneal staining scores, and decreased IRAK4, MMP9, and TNF-α expression in the corneal epithelium. PA alleviates ocular surface inflammation and improves DE phenotypes by targeting the IRAK4/JAK1/STAT1 signaling pathway. These findings highlight PA as a promising therapeutic candidate for DE and provide new mechanistic insights into IRAK4-mediated inflammation regulation.