Objective To observe the expression changes of VEGF, iNOS and the level of MVD and NO during the evolution of Golden hamster cheek pouch carcinogenesis. To observe the pathological change during the evolution of Golden hamster cheek pouch carcinogenesis. To study the effect of NO in carcinogenesis in the pouch of hamster, and to investigate the effect of NOS in- hibiter I-NAME in interfering with carcinogenesis. Methods 90 golden hamsters were divided into three groups: 40 in experi- ment group, 40 in control group and 10 in blank group. DMBA was painted on hamsters cheek pouch in experiment and control group, L-NAME was given to hamster in experiment group at the dose of 0.02 ml/g. Hamsters were killed at 6,9, 12 and 16" weeks, respectively. The blank group was killed at the 16" week. SABC immunohistochemistry assay was used to detect the expression of iNOS, VEGF and factor related antigen. MVD。measured. The level of NO was measured by Spectrophotometry . Results The difference between control group and experiment group at the 12' week and 16" week was observed. The difference of positive expression rate of iNOS in all group was significant and difference between blank group and control group~signifi- cant, The difference of positive expression rate of VEGF in all group was significant and difference between blank group and control group at the 12" and 16"week was significant; there was significant difference in every group MVD from the 6'" week control group to the 160' week control. There were significant difference among the control group, except the 6' week of experiment and control group. Conclusion There is an increased expression of iNOS and the level of N0, as well MVD during the evolution of Golden hamster cheek pouch carcinogenesis from slightly dysplasia to invasive carcinoma. NO plays an important role during the evolution of carcinogenesis, and iNOS inhibitor L-NAME can inhibit the carcinogenesis.
