• Journal of Radiation Protection and Research
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• v.24 no.1
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• pp.17-22
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• 1999

This study was carried out to evaluate the biochemical and morphological effects of ionizing radiation on mouse ovarian follicles. Immature mice (ICR, 3 week-old) were irradiated with a dose of $LD_{80(30)}$ at KAERI. The ovaries were collected after 6 hours, 12 hours, 1 day, and 2 days post irradiation. With the morphological basis of the histological staining with hematoxylin-eosin, immunohistochemical preparation using in situ 3'-end labeling was evaluated. Flowcytometric evaluation of DNA extracted from the whole ovary was performed. The percentage of $A_0$ (subpopulation of cells with degraded DNA and with lower DNA fluorescence than $G_0/G_1$ cells), apoptotic, cells in the cell cycle was significantly higher in the irradiated group than in the control group. The number of in situ 3'-end labeled follicles increased at 6 hours post irradiation. All the analyses represented that the ionizing radiation-induced follicular atresia was taken place via an apoptotic degeneration. Such a degeneration underwent very fast and acutely. Therefore, it is concluded that the radiation-induced follicular degeneration is, like the spontaneous atresia, mediated by an acute apoptosis of follicular granulosa cells. Flowcytometric evaluation of cell cycles can make the role for quantifying the atretic follicles and understanding the mechanism of the radiation-induced cell death.

• Korean Journal of Environmental Biology
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• v.22 no.3
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• pp.411-418
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• 2004

Mercury, one of the most diffused and hazardous organ-specific environmental contaminants, exists in a wide variety of physical and chemical states. The murcury with the nature which evaporates easily can cause an acute or chronic mercury poisoning to workers at mercury-handling workplaces. Although many studies indicate that mercury induces a deleterious damage, little has been reported from the investigations of mercury effects at surrounding levels in living things. The purpose of this study was to evaluate the biological effects of mercury chloride and ionizing radiation. Prepubertal male F344 rats were administered mercury chloride in drinking water throughout the experimental period or were given wholebody irradiation with a dose of 6.5 Gy. The amount changed of body weight during the experimental period showed a 4.9% rise in the mercury-treated group and 14.4% decline in the irradiated group compared with the level of the control group. The results of hematological analysis (red blood cells, white blood cells, hemoglobin, and hematocrit) indicated the differential effects of mercury chloride and ionizing radiation. However the concentration of cortisol as assessed by radioimmunoassay increased in both of the groups. Relative expressions of mRNA related to mitochondrion-mediated apoptosis were investigated using semiquantitative reverse transcription polymerase chain reaction on gonad and urinary organs of the experimental groups. While the expression of Bcl-2 mRNA exhibited different patterns depending on the organs or the experimental groups, both of the experimental groups showed a conspicuous expressions of Bax mRNA. In conclusion, the target organ of mercury chloride seems to be a urinary organ and the pattern of damage induced by mercury chloride differs from that by ionizing radiation.

• Journal of Radiation Protection and Research
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• v.24 no.2
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• pp.87-92
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• 1999

The present study was carried out to evaluate the morphological changes in the degenerating primordial follicles induced by $\gamma$-radiation. The prepubertal female mice of three weeks old ICR strain were whole-body irradiated with a dose of $LD_{80(30)}$ (8.3 Gy). The ovaries were collected at 0 h, 3 h, 6 h, and 12 h post-irradiation. The largest cross sections were prepared with histological semi-thin sections and then observed microscopically. The ratio of normal to atretic follicles was reduced significantly after 6th post-irradiation. At 6 h post-irradiation, the number of degenerated primordial follicles increased. Germinal vesicles disappeared, and lipid droplets increased. No more ooplasmic membranes were seen. Granulosa cells became round in shape, and apoptotic cells started to appear. The ratio of normal to atretic follicles in the control group was 62.50%. The ratio decreased with time after irradiation. The ratio decreased down to 51.61 %, 48.97 %, 11.11 %, and 7.14 % at 0 h, 3 h, 6 h, and 12 h, respectively. Taken together, ionizing radiation acutely induced the degeneration of primordial follicles. The patterns of degeneration are 1) apoptosis of one or more granulosa cells with relatively intact oocyte, 2) apoptosis of oocyte with intact follicle cells, or 3) apoptotic degenerations of both cells. The Present study can provide morphological clues for the identification of degenerating primordial follicles.