BACKGROUND: ZEB1, a zinc-finger E homeobox-binding transcription factor most frequently associated with developmental programs linked to epithelial-mesenchymal transition, has been demonstrated to regulate immune cell function. The study aimed to investigate the expression pattern of ZEB1 in Th17 cells and its colocalization with p-STAT3 in human apical periodontitis lesions. METHODS: Thirty-nine human periapical tissues were collected for ex vivo study, including periapical granulomas (PGs, n = 14), radicular cysts (RCs, n = 12), and healthy control tissues (control group, n = 13). Inflammatory infiltration of the lesions was assessed using hematoxylin-eosin staining. The expression of ZEB1 was detected and analyzed by immunohistochemistry. The localization of ZEB1 in Th17 cells and its colocalization with p-STAT3 were assessed using fluorescence colocalization. RESULTS: ZEB1 expression was significantly higher in PGs and RCs than in the healthy control group
however no significant difference between the two groups was observed. Immunofluorescence analysis revealed that ZEB1 expression was correlated with IL17 and CD4 double-positive cells in human periapical lesions. ZEB1/ p-STAT3 double-positive cells were predominant in RCs and PGs than in the healthy control group. CONCLUSIONS: The expression of ZEB1 was significantly elevated in PGs and RCs, and correlated with Th17 cells and p-STAT3 expression. This study revealed that ZEB1 is a potential player correlated with STAT3 activation and Th17 cells in apical periodontitis pathogenesis.