Chemopreventive Effect of Aspirin on N-Butyl-N-(4-hydroxybutyl) Nitrosamine Induced Preneoplastic Lesions in Rat Bladder / 대한비뇨기과학회지

ABSTRACT

PURPOSE: We investigated the possible inhibitory effect of aspirin during the initiation and post initiating stages on N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN) induced bladder carcinogenesis in female rats. MATERIALS AND METHODS: Forty-five female Sprague-Dawley rats were divided into three groups. Group A received 0.05% BBN in drinking water for 12 weeks. Group B re ceived 0.05% BBN in drinking water with 0.5% aspirin in the diet for 12 weeks. Group C received control diet without added chemicals. The rats were sacrificed after 12 weeks. For identification of chemopreventive effect of aspirin, apoptosis was detected by in situ cell death detection method. The apoptotic index (AI) was calculated from the ratio of typical apoptotic cells relative to the total cells from observation of at least 1000 cells in each preneoplastic lesion among the groups. RESULTS: All cases of group A showed multiple lesions of simple and focal hyperplasia. The incidence of papilloma was 80% in group A. All cases of group B also showed multiple lesions of simple and focal hyperplasia but the incidence of papilloma was decreased to 20%. The total numbers counted of focal hyperplasia and papilloma lesions were significantly reduced in group B than in group A (p<0.001 and p<0.001, respectively). The mean AI in group A and B sequentially increased in preneoplastic lesions, as compared to that in the normal epithelium of the rat bladder. Significant differences in AI in the lesions of simple and focal hyperplasia between group A and B were noted (p<0.001 and p<0.001, respectively). CONCLUSIONS: The result suggests that aspirin significantly decreases the incidence of precancerous lesions and it can act as a chemopreventive agent for precancerous lesions of urinary bladder.