Effects of cis-dichlorodiammineplatinum alone and in combination with ionizing radiation of the esophageal mucosa: a scanning and transmission electron microscopic study.

Cis-dichlorodiammineplatinum (cis-DDP) has for more than 20 years been part of the therapeutic arsenal of oncology. Most of the knowledge about its biological action is based on clinical investigations and therefore an examination of the influence of cis-DDP at the cellular and sub-cellular level is necessary. Five mg of cis-DDP was given intraperitoneally (i.p.) to ten rabbits. Ultrastructural examinations were performed on the upper and lower parts of the esophagus each day after the injection on the following ten days. Another 50 rabbits were given 5 mg cis-DDP and were irradiated in an area just beneath the hypopharynx. They were given 2 Gy at each irradiation and were maximally treated with up to 20 Gy. Examinations were carried out from the first day after the final treatment and each day during ten consecutive days. Five animals were used as controls. Cis-DDP proved to have a deleterious effect on the epithelial layer of the esophageal mucosa with cell loss and structural disarrangement of the microridges and whorls on the surface. This finding was an early phenomenon and lasted for all ten examination days. The changes were not more exaggerated when irradiation was added to the experiments. Repopulation of new cells from the matrix was noticed about five days after the administration of cis-DDP alone.