Effects of caffeine and saccharin on DNA in the bladder epithelium of rats treated with N-butyl-N-(3-carboxy-propyl)-nitrosamine.

The damage to DNA caused by N-butyl-N-(3-carboxypropyl)-nitrosamine (BCPN), saccharin and caffeine in the urinary bladder epithelium of female rats and its subsequent repair was investigated using alkaline sucrose density gradient analysis with a fluorimetric procedure for DNA determination and light and electron microscopy. Exposure of the bladder epithelium to 50 mg/kg body wt. of BCPN solution for 5 min resulted in serious damage of DNA within 2 h. Subsequent repair of most of the DNA damage, as indicated by reconversion of low molecular weight DNA fragments to larger ones, began after 6 h, and appeared to be complete after 48 h. Caffeine and saccharin induced no remarkable changes in the sedimentation profiles of DNA of the epithelial cells, with or without pretreatment of the cells with BCPN (administered to rats as 0.05% BCPN in the drinking water for 4 weeks). These results were confirmed by light and electron microscopy.

PMID: 7357676 [PubMed - indexed for MEDLINE]