TISSUE REACTION FOLLOWING INTRATRACHEAL APPLICATION OF ROENTGEN CONTRAST-MEDIA IN RATS

Contrast media (CM) given orally for roentgen examination of the upper gastrointestinal tract may inadvertently enter the lungs. The present paper describes the local effects on the lungs of rats after a single intratracheal instillation of the nonionic, isoosmolar, dimeric CM io dixanol and iotrolan, and the ionic, hyperosmolar, monomeric CM diatri zoate. Hydrochloric acid (HCl) and saline were included as positive an d negative controls, respectively. The test compounds were given by in tratracheal instillation to anesthetized rats at dose volumes of 0.5 m l/kg b.w. The animals were killed 6 hours, 24 hours or 7 days after do sing, and the trachea and lungs subjected to histopathological examina tion. Acute signs of dyspnea were observed in 7 out of 15 animals that received HCl. No clinical signs could be related to treatment with an y of the CM. Histomorphological assessment of the respiratory tract di d not reveal any CM-related adverse effects, whereas animals treated w ith HCl showed marked histopathological changes. The results indicate that accidental exposure of the respiratory system to iodixanol, iotro lan or diatrizoate is unlikely to cause any significant tissue damage or lead to respiratory complications.