Alterations in the rat kidney associated with sodium saccharin feeding: a scanning electron microscopic study

Sodium saccharin has previously been demonstrated to induce hyperplasia of the urothelium of the rat kidney pelvis. It was fed as 5% of the diet to male F344 rats for 18 weeks. In the present experiment, scanning electron microscopy (SEM) was utilized to detect early morphologic changes. Pleomorphic microvilli (PMV) were observed in all four sodium saccharin-fed rats, located on cells at the junction of the papilla and pelvis. PMV also occurred at the papilla-pelvic junction in three of the ten control rats, but the affected area was smaller and the PMV exhibited less severe atypia.