Epigallocatechin-3-gallate decompression irrigation effectively relieves odontogenic keratocyst by inhibiting the expression of inflammatory factors of the PD-L1 signaling pathway

Odontogenic keratocysts are oral diseases that present with aggressive and highly recurrent lesions. The aim of the present study was to assess the clinical viability of utilizing epigallocatechin-3-gallate extracted from green tea as a decompression irrigation treatment for OKC. A total of 20 patients with OKCs who underwent decompression were divided into an EGCG decompression group and a normal saline decompression group. By transcriptome sequencing, 403 differentially expressed genes of OKC samples obtained before and after 6 months of decompression/EGCG treatment were screened. Gene Ontology analysis revealed that the primary functions of these genes involved immune and inflammatory responses. Programmed cell death protein 1, an inhibitory receptor, along with its ligand programmed death-ligand 1, could trigger a coinhibitory signal in activated T cells. These receptors and ligands played a crucial role in the differentiation, exhaustion and apoptosis of T cells. Three inflammatory factors, namely IL-7R, C-X-C motif ligand 1 and Toll-like receptor 2, which are closely linked to PD-L1, were significantly downregulated after EGCG treatment, as validated by protein-protein interaction analysis and in clinical tissue samples. The findings suggested that EGCG treatment for OKC could potentially target PD-L1 as a therapeutic option.