The effect of topical vitamin C on palatal oral mucosal carcinogenesis using 4-nitroquinoline-1-oxide.

Vitamin C is an essential nutrient whose protective influence in carcinogenesis has been reported frequently. In general, evidence suggests that vitamin C inhibits the formation of some carcinogens and decreases the incidence and delays the onset of neoplastic lesions but the mechanisms by which this occurs are not known. In 1973, Wallenius and Lekholm induced intra-oral palatal squamous cell carcinomas by the use of the water soluble carcinogen 4-nitroquinoline-1-oxide (4NQO) applied thrice weekly to the palatal mucosa of rats. The aim of this study was to determine if in rats topically applied vitamin C had an effect on the process of carcinogenesis caused by the application of 4NQO. The results of this study showed that in the 4NQO treated animals a progression through mild, moderate and severe dysplasia occurred prior to neoplastic changes at 24 weeks and that this progression was delayed in the animals treated topically with vitamin C. It can be concluded that topically applied vitamin C has a modulating effect on the neoplastic process induced by 4NQO in the palatal mucosa of rats.