Evaluation of transforming growth factor beta1 gene in oral submucous fibrosis induced in Sprague-Dawley rats by injections of areca nut and pan masala (commercial areca nut product) extracts.

CONTEXT: Oral submucous fibrosis (OSF) is a potentially malignant oral disorder causally linked to the habit of chewing arecanut. The pathogenesis of the disorder is multifactorial and transforming growth factor beta (TGF-beta) is a prominent player in the induction of fibrosis. The alkaloids of the arecanut seem to target the TGF-beta and the deposition of collagen is predominantly mediated through this cytokine.

AIMS AND OBJECTIVES: The present study attempts to induce OSF in Sprague-Dawley rats by injections with solutions of arecanut and pan masala extracts. The tissues were then analysed for the TGF-beta1 gene by real time polymerase chain reaction. (rtPCR).

MATERIALS AND METHODS: Buccal mucosa of Sprague-Dawley rats were injectedwith arecanut and pan masala solutions on alternate days over a period of 48. weeks. Quantitative real time PCR was done to assess the expression of TGF-beta1 in the tissues.

RESULTS: OSF-like lesions were seen in both the arecanut and pan masala.treated groups. The histological changes included atrophic epithelium, partial or complete loss of rete ridges, juxta-epithelial hyalinization, inflammation and accumulation of dense bundles of collagen fibers subepithelially. Quantitative real-time PCR showed a significant upregulation of TGF beta1. A. peak fold change of 4.74 in the 18th. week was observed for the arecanut group while the pan masala group recorded a peak change of 4.9 in the 24th. week.

CONCLUSION: The study provides further evidence that arecanut and pan masala induce oral submucous fibrosisvia the TGF beta1 pathway.