ELECTRON MICROSCOPIC STUDY OF THE SPILT IRRADIATION EFFECTS ON THE RAT PAROTID DUCTAL CELLS

방사선 분할조사가 타액선 도관세포에 미치는 영향에 관한 전자현미경적 연구

This study was designed to investigate the effects of split irradiation on the salivary ductal cells, especially on the intercalated cells of the rat parotid glands. For this study, 24 Sprague-Dawley strain rats were irradiated on the head and neck region with two equal split doses of 9Gy for a 4 hours interval by Co-60 teletherapy unit, Picker's model 4M 60. The conditions of irradiation were that field size, dose rate, SSD and depth were 12×5㎝, 222 cGy/min, 50㎝ and 1㎝, respectively. The experimental animals were sacrificed 1. 2, 3, 6, 12, hours and 1, 3, 7, days after the irradiation and the changes of the irradiated intercalated cells of the parotid glands were examined under light and electron microscope. The results were as follows: 1. By the split irradiation, the degenerative changes of intercalated cells of the parotid glands appeared at 3 hours after irradiation and the most severe cellular degeneration observed at 6 hours after irradiation. The repair processes began from 12 hours after irradiation and have matured progressively. 2. Under electron microscope, loss of nuclear membrane, microvilli and secretory granules, derrangement of chromosomes, degeneration of cytoplasm, atrophy or reduction of intracytoplasmic organelles were observed in the intercalated ductal cells after split irradiation. 3. Under light microscope, derrangement of ductal cells, widening of cytoplasms and nuclei, hyperchromatism and proliferation of ductal cells were observed in intercalated ducts after split irradiation.