Published online Dec 21, 2007. doi: 10.3748/wjg.v13.i47.6379
Revised: September 8, 2007
Accepted: November 17, 2007
Published online: December 21, 2007
AIM: To investigate the link between chronic biliary inflammation and carcinogenesis using hamster gallbladder epithelial cells.
METHODS: Gallbladder epithelial cells were isolated from hamsters and cultured with a mixture of inflammatory cytokines including interleukin-1β, interferon-γ, and tumor necrosis factor-α. Inducible nitric oxide synthase (iNOS) expression, nitric oxide (NO) generation, and DNA damage were evaluated.
RESULTS: NO generation was increased significantly following cytokine stimulation, and suppressed by an iNOS inhibitor. iNOS mRNA expression was demonstrated in the gallbladder epithelial cells during exposure to inflammatory cytokines. Furthermore, NO-dependent DNA damage, estimated by the comet assay, was significantly increased by cytokines, and decreased to control levels by an iNOS inhibitor.
CONCLUSION: Cytokine stimulation induced iNOS expression and NO generation in normal hamster gallbladder epithelial cells, which was sufficient to cause DNA damage. These results indicate that NO-mediated genotoxicity induced by inflammatory cytokines through activation of iNOS may be involved in the process of biliary carcinogenesis in response to chronic inflammation of the biliary tree.