The Dynamic Changes of Nitric Oxide Level Hamster Buccal Pouch Carcinogenesis

Objective: To assess the role of nitric oxide in the golden hamster pouch carcinogenesis induced by 7,12-dim-ethylbenzanthracene( DMBA). Methods: Seventy-two outbred six-week old Syrian golden hamster were randomly divided into one experimental group (60 animals) and one control group (12 animals). The control group remained untreated. The pouches of the experimental group were painted with 0. 5% DMBA solution three times each week. Light microscope was used to observe the pathologic changes. The serum nitric oxide level was measured by chemical photometry. The expression activity of the inducible nitric oxide synthase was observed by immunohistochemistry. Results: In oral carcinoma group serum NO level and iNOS protein expression were significantly increased compared with the normal or hyperplasia group (P 0. 05) , No iNOS protein expression could be detected in the untreated pouches. There was a significant relationship between iNOS protein expression and serum NO level (rs =0.590, P0.01). Conclusion: Increased NO level could contribute to the mechanism for experimentally induced oral carcinogenesis.