Abstract
Chitosan stimulates the fibroblastic, endothelial, and intestinal epithelial cells to release chemotactic inflammatory cytokines, especially interleukin 8 (IL-8). Tannic acid (TA) has a variety of biological activities, such as anti-inflammatory, anti-viral effects. However, the pre-treatment of TA on chitosan polymer-induced IL-8 production from epithelial cells has not been well studied. This study focused on the effect of TA on chitosan polymer-induced IL-8 production in the oral mucosal epithelium as estimated by HSC-2 cells established from a human oral squamous cell carcinoma. The intracellular IL-8 production was measured by flow cytometry. The chitosan polymer-induced production of IL-8 decreased after pre-treatment with TA. IL-8 mRNA was measured by real-time PCR, and its mRNA expression level was reduced after TA pre-treatment. Antibody-based assays were used to investigate the effect of chitosan and TA on the activation of mitogen-activated protein kinases (MAPKs). These investigations showed the pre-treatment effects of TA on IL-8 production to be mainly mediated through the inhibition of the p38 MAPK pathways. The present study demonstrated that TA pre-treatment reduced the intracellular IL-8 production in HSC-2 cells via the MAPK signaling pathways. These findings indicate that the combined application of TA and chitosan may be clinically beneficial for the inflammatory lesions of the oral mucosa.
