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[Expression and significance of inducible nitric oxide synthase and vascular endothelial growth factor in carcinogenesis of hamster cheek pouch].

BACKGROUND & OBJECTIVE
Inducible nitric oxide synthase (iNOS) and vascular endothelial growth factor (VEGF) are related to carcinogenesis and development of tumors. This study was to explore the correlations of the expression of iNOS and VEGF to the angiogenesis in carcinogenesis of Golden hamster cheek pouch.


METHODS
A total of 50 Golden hamsters were divided into 2 groups: 40 in experiment group, 10 in control group. DMBA was painted on the cheek pouches of the hamsters in experiment group, but not in control group. The hamsters in experiment group were killed at the 6th, 9th, 12th, and 16th weeks, respectively; 10 at each time. The hamsters in control group were killed at the 16th week. The expression of iNOS and VEGF and microvessel density (MVD) in carcinogenesis in the pouches of hamsters were detected by SABC immunohistochemistry; the level of nitric oxide (NO) was measured by spectrophotometry.


RESULTS
Both iNOS and VEGF expression were negative in the pouches of the hamsters in control group, but they increased gradually from the 6th to 16th week in experiment group (P<0.05). The level of NO increased from the 6th to 16th week, too, and the difference between each 2 groups was significant (P<0.05). MVD was significantly higher in iNOS- and VEGF-positive group than in iNOS- and VEGF-negative group (P<0.05).


CONCLUSIONS
NO plays an important role in the carcinogenesis of Golden hamster cheek pouch. iNOS and VEGF may exert interactions in tumor angiogenesis.