180200-68-4

The present experiment is designed to assess the potential chemopreventive properties of Tilmacoxib (JTE-522), a new selective cyclooxygenase-2 inhibitor, on the induction of 1,2-dimethylhydrazine (DMH)-induced colonic aberrant crypt foci (ACF), a marker of rat colon carcinogenesis. A total of 80 male F344 rats are treated with 3 or 10 mg/kg of body weight Tilmacoxib or vehicle by oral gavage five times weekly from the start of the experiment. One week later, rats receive s.c. injections of saline or 20 mg/kg of body weight DMH once weekly for four successive weeks. At the end of 12 weeks after the start of experiment, all rats are sacrificed and colons are evaluated for ACF. 10 mg/kg Tilmacoxib significantly suppresses the total ACF/colon. No inhibitory effect is observed in the 3 mg/kg Tilmacoxib treatment group. Administration of 10 mg/kg Tilmacoxib significantly suppresses ACF formation with a 30% reduction in total ACF/colon (p<0.01). Furthermore, the data on crypt multiplicity show that 10 mg/kg Tilmacoxib significantly reduces the formation of foci containing 1-3 crypts but not foci containing four crypts or more. Administration of the low dose of Tilmacoxib (3 mg/kg) has no inhibitory effects on either the total ACF or crypt multiplicity^[3].