방사선 조사에 의한 흰주 난포의 퇴축과 난포세포의 방사선 감수성 = Radiation-induced Follicular Atresia and Radiation Susceptibility of Follicular Cells in the Rat Overy

다국어 초록 (Multilingual Abstract)

The aim of this study were to investigate radiation-induced atresia and radiation susceptibility in the rat ovary morphologically. Female rats (Sprague Dawley strain) of 4 weeks old were irradiated with dose of 4 Gy and 8 Gy, and sacrificed at hour 6, 12, and 24 after radiation. The H & E stain, the TUNEL method (ApopTag kit) and transmission electron microscopy (TEM) were used.
In light microscopic observation, the number of atresia of ovarian follicles were increased significantly at 6h after irradiation (p<0.01). There was no significant difference between 4 Gy and 8 Gy irradiated groups. In TEM observation, granulosa cells in radio-sensitive follicles were characterized by several structural features including condensation of nuclear chromatin granules, nuclear fragmentation and apoptotic body formation. An apoptotic cell is observed to have been phagocytosed by a normal granulosa cell. Granulosa cells in radio-resistant follicles were characterized by several structural features including nuclear indentation, partial condensation of chromatin granules, mitochondrial swelling, dilatation of RER cisterns, accumulation of dense irregular masses, accumulation of lipid droplets, and increased lysosomal bodies. Number of gap junctions between granulosa cells were decreased, and intercellular space were widen than that of control animals. These findings were prominent at 6h after irradiation and were diminished at 12h and 24h after irradiation.
With these results, it was concluded that radiation-induced follicular cell apoptosis and ovarian follicular atresia in rat ovary increased considerably at 6h after irradiation. Further studies are needed to reveal the more extensive differences between radiosensitive and radioresistant follicular granulosa cells.