Effect of areca extract, arecaidine and lime on oral mucosa

Objective: Paan chewing has been implicated as an important aetiological factor in the development of oral cancer and oral submucous fibrosis. Although the effect of a number of individual constitutents such as arecoline and arecaidine have been studied extensively in vitro, little is known about their direct effect on the epithelium. The aim of this study, therefore was to investigate the effect of areca nut extract, arecaidine and lime on viability and cytokine production by a stratified in vitro reconstituted oral mucosa. Methods: A crude aqueous extract of areca nut (ANE), arecaidine (10-3M) or slaked lime (500ìg/ml) were applied to the epithelial surface of a 14day oral buccal mucosal model (SkinEthic; Nice; France). PBS and 0.5%SLS treatment were included as controls. Viability and cytokine production (IL-8, MMP-1 and TIMP-2) were assessed after 24 hours using a modified MTT assay and commercial Quantikine ELISA kits (R&D Systems, UK).

Results: SLS significantly increased IL-8 (2529 ± 100pg/ml; p<0.05) and MMP-1 release (25 ± 8pg/ml), but reduced TIMP-2 production (1339 ± 113pg/ml) and epithelial viability (66 ± 7%) compared to PBS treated controls (IL-8 1998 ±322pg/ml; MMP-1 9 ±1pg/ml; TIMP2 -1636±146pg/ml; Viability 100± 3%). ANE however significantly reduced IL-8 (394 ± 70pg/ml); MMP-1 (2.4 ± 0.2pg/ml); TIMP-2 (457 ± 65pg/ml) and viability (82 ±3%) whereas arecaidine and lime had no significant effect.

Conclusions: The inhibitory effect of ANE on the viability and cytokines release by the mucosal model supports recent studies on involucrin expression by normal keratinocytes (Tseng etal 2006 Oral Oncol in press). Further studies are in progress to evaluate which component of the extract is causing these changes