[Ultrastructure of cultured normal bladder transitional epithelial cell and BBN induced rat bladder tumor cell lines].

A normal rat bladder transitional epithelial cell line and seven tumor cell lines cultured from tumor induced by 0.05% N-Butyl-N-4-hydroxybutyl-Nitrosamine (BBN) were established and a comparative study on the doubling time and Ultrastructure of the cultured cell lines was performed. 1. Seven cultured cell lines (TU-B1 1-7) were obtained from bladder tumors induced by the administration of BBN for 32 weeks. 2. The doubling time of the cultured tumor cell lines were 43, 24, 28, 24, 25, 31, and 45 hours, suspectively. 3. These cultured tumor cell line were inoculated subcutaneously into nude mice and transitional epithelial carcinomas differing in degree of differentiation were observed. 4. Horizontal and tangential sections of these cultured tumor cell lines were examined by transmission electron microscopy. The development of intracellular organella and the presence of microvilli on the surface of the cells were noted. Intracellular adhesion was poor but the morphological characteristics of bladder transitional epithelium with compressed vesicles and other intracellular structures such as desmosome and free ribosomes were observed. 5. By applying the attached collagen gel method to our cell lines, it was possible to obtain cultured rat epithelial cells with the same morphology as in vivo, in addition to the tumor cell lines. 6. These cultured cell lines of normal rat transitional epithelium appear to be useful a experimental models with which one could clarify the function of the transitional epithelium and the mechanisms of bladder carcinogenesis.