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Effects of Prenatal Irradiation with an Accelerated Heavy-Ion Beam on Postnatal Development in Rats:III .Testicular Development and Reproductivity
利用統計を見る
Effects on gonads in prenatal male fetuses, and on the postnatal testicular
development and reproductivity of male offspring were studied following
exposure of pregnant Wistar rats to either accelerated carbon-ion beans with
a LET value of about 13 keV/mm or neon-ion beams with a LET value of about
30 keV/mm at a dose range from 0.1 Gy to 2.0 Gy on gestation day 15.
Induction of apoptosis in fetal gonocytes was evaluated pathologically in
male gonads. Mean number of pups, preweaning mortality, and the age for
testis descent in offspring were examined. Testis weight and the ratio of it
to body weight were measured on postnatal days 30, 60 and 90, respectively.
Development of testicular tubules was analyzed histologically. In addition,
in the male offspring, the successful mating rates with non-irradiated
female rats, the mean number of pups descended, and the weaning rates of the
pups were investigated. The effects of X-rays at 200 kVp estimated for the
same biological end points were studied for comparison. For heavy ions, a
dose of 2.0 Gy caused 100% preweaning mortality. For some endpoints, such as
preweaning mortality, testis weight, and ratio of testis weight to body
weight, significant alteration was observed in offspring prenatally received
only 0.1 Gy of accelerated neon ions; while for the most endpoints regarding
the effects from carbon ions or X rays, a significant alteration could be
observed only when a dose was at 0.5 Gy or more. In this dose range,
apoptosis in gonocytes of fetal gonads was significantly induced in a
dose-dependent manner with a peak at around 12 to 18 hr after irradiation;
in the prenatally irradiated pups, statistical significances for increased
prenatal death, delayed accomplishment in testis descent, low testis weight,
changed ratios of testis weight to body weight, and increased malformed
testicular tubules were recorded. When the dose was at 1.0 Gy or 1.5 Gy,
marked decrease in successful mating rates was also observed for the
prenatally irradiated male rats with the non-irradiated female rats. On the
other hand, for the animals descended from both the prenatally irradiated
male rats and the non-irradiated female rats, significant increase in
prenatal death and in preweaning mortality was scored when the father rats
were prenatally irradiated with 0.5 Gy or more. These findings indicated
that prenatal irradiations on gestation day 15 generally induced markedly
detrimental effect on fetal development, postnatal testicular maturation and
male reproductivity in rats, which was a dose and LET-related event.
会議概要（会議名, 開催地, 会期, 主催者等）
COSPAR Colloquium(Mutagenic consequences of the space emvironment)
Effects of Prenatal Irradiation with an Accelerated Heavy-Ion Beam on Postnatal Development in Rats:III .Testicular Development and Reproductivity
