Morphological changes of microvilli on different surfaces of epithelial cells in the rat bladder treated with N-butyl-N-(4-hydroxybutyl) nitrosamine.

This study investigates morphological changes of microvilli occurring on different surfaces of epithelial cells, including luminal surfaces, intercellular surfaces, and basal cell surfaces adjacent to the basement membrane (BM), in the rat bladder treated with N-butyl-N(4-hydroxybutyl) nitrosamine (BBN) by transmission electron microscopy (TEM). The present results showed that the microvilli were observed not only on the luminal surfaces of epithelial cells but also on the intercellular surfaces and basal cell surfaces adjacent to the BM following administration of BBN. There were a variety of morphological changes of microvilli on the luminal surfaces, intercellular surfaces and basal cell surfaces adjacent to the BM, respectively. It is suggested that the microvilli occurring on the luminal surfaces may not represent characteristics of the microvilli occurring on the intercellular surfaces and on the basal cell surfaces adjacent to the BM, and that occurrence of the microvilli on the epithelial cell surfaces may reflect a higher metabolic activity of proliferative epithelial cells and may play an important role in the processes of tumor growth during bladder carcinogenesis.