Abstract

Function of salivary gland is severely disturbed during the radiotherapy for the patients with the head and neck cancers. Primary saliva is secreted by the glandula acini, but the various secretion from the ductal cells and the electrolyte control of ductal cells influence the component and character of the final saliva. In this study, the radiation effect on the duct cells of rat parotid gland was studied. Under sodium thiopental anesthesia, male rats weighing 200~250 g each were exposed to the radiation source of Mitshubishi linear accelerator(ML-4MV). Head and neck regions were exposured within the area of 30 30 cm, at the distance of 80 cm, in the depth of 1.2 cm, by the speed of 200 rads/min. Total doses were 3,000rads or 6,000 rads, and the survival times were 6 hours, 2 days or 6 days, respectively. Parotid glands were fixed in the 2.5% glutaraldehyde-l.5% paraformaldehyde solution, followed by refixation in the 1% osmic acid solution. Tissues were embedded within the araldite mixture. Thin sections were stained with the uranyl acetate-lead citrate solution. From the electron microscopic study, the following results were nbtained, l) Intercalated duct ce11s of the rat parotid gland were relatively organelle-poor, and they contained same secretory granules. Striated duct cells showed typical basal striations formed by the parallel infoldings together with the large number of mitochondria between the infoldings. Striated duct cell contained only a few secretory granules. 2) Following the irradiation, many intercalated duct cells showed atrophic change, thereafter content of secretory granule were increased, even without any structural recovery of the cyto- plasm. 3) The striated duct cells also showed the radiation effects. On the basal cytoplasm, the striations were disorganized or disappeared. But the content of secretory granules in the supranuclear region was largely increased. 4) Myoepithelial cells were altered or degenerated. It means that the autonomic control of ductal cell secretion is also distrubed. The cytology of the duct cells following the irradiation was interpreted as that, cessation or extreme slow-down of the secretory procedure was occurred by high dose irradiation. The electrolyte control function of the striated duct cell might be severely disturbed.

• Keywords: Ultrastructure, Secretory duct, Parotid gland, Radiation