Electron Microscopy of Irradiated Cells of the Follicular Epithelium of the Rat Thyroid

Abstract

Electron microscope studies of the follicular epithelium of adult male white rats injected intraperitoneally with 1.5 mc of radioiodine and killed 4 days later showed changes in the ergas-toplasm, mitochondria, and microvilli. The sac structure of the ergastoplasm broke down into small ovoid bodies. Mitochondria, after swelling became vacuolate and degraded to small dark structures. An increase in lipid material seemed to occur. Microvilli disappeared and a protoplasmic lamina appeared between colloid and epithelium. Such changes in cell particulates were not detectable in untreated rats. Similar studies of X-ray irradiated rat thyroids revealed no changes when compared to controls. Implications of the changes produced with radioiodine are discussed.