Effect of Catechins on Cytokine Production in Human Odontoblast-like Cells

Green tea catechins have potent anti-inflammatory properties and anti-oxidative activities. We previously demonstrated that epigallocatechin-3-gallate (EGCG), a major component of green tea catechins, reduced proinflammatory cytokine production in dental pulp fibroblasts exposed to bacterial components. In pathological condition such as carious lesion, odontoblasts located in the front line of host defense in dental pulp tissues are also activated by microbial irritation to secret cytokines as well as extracellular matrix proteins. Objectives: The purpose of this study was to evaluate the effect of catechins on cytokine production in human odontoblast-like cells. Methods: Human dental pulp cells were obtained from explant cultures of minced pieces of pulp tissues from non-carious premolars extracted for orthodontic reasons. To induce odontoblast-like cells, the dental pulp cells were cultured in Dulbecco's modified Eagle's medium supplemented with 10% fetal bovine serum, antibiotics, b-glycerophosphate and ascorbic acid. Mineralized nodule deposition in the cells was stained by alizarin red staining. The odontoblast-like cell with and without EGCG pre-treatment were exposed to lipopolysaccharide (LPS) or peptidoglycan (PGN). Interleukin-8 (IL-8) production in culture supernatants was measured by ELISA, and IL-8 mRNA expression was determined by RT-PCR. Results: The odontoblast-like cells in the present study formed mineral deposition stained positive with arizarin red. EGCG treatment significantly reduced IL-8 expression in odntoblast-like cells stimulated with LPS or PGN in concentration-dependent manner. Conclusion: We demonstrate here that catechins have inhibitory effect on proinflammatory cytokine production in odontoblast-like cells. These findings suggest that green tea catechins may prevent the exacerbation of pulpitis.