• Korean Journal of Exercise Nutrition
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• v.16 no.2
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• pp.73-84
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• 2012

Thyroid hormones are important for the development of the brain including the cerebellum. In the present study, we investigated the effect of treadmill exercise on the survival of Purkinje neurons and the activation of astrocytes in the cerebellar vermis of hypothyroidism-induced rat pups. On the day of perinatal 14, pregnant rats were divided into two groups (n = 5 in each group): the pregnant control group and the pregnantmethimazole (MMI)-treated group. For the induction of hypothyroidism in the rat pups, MMI was added to the drinking water (0.02% wt/vol), from the day of perinatal 14 to postnatal 49. After delivery, male rat pups born from the pregnant control group were assigned to the control group. Male rat pups born from the MMI-treated group were divided into the hypothyroidism-induction group, the hypothyroidism-induction with treadmill exercise group, and the hypothyroidism-induction with thyroxine (T4) treatment group (n = 10 in each group). The rat pups in the exercise group were forced to run on a treadmill for 30 min once a day for 4 weeks, starting on postnatal day 22. In the hypothyroidism-induced rat pups, motor coordination was reduced and Purkinje cell death and reactive astrocytes in the cerebellar vermis were increased. Treadmill exercise enhanced motor coordination, increased the survival of Purkinje neurons, down-regulated reactive astrocytes, and enhanced brain-derived neurotrophic factor (BDNF) and receptor tyrosine kinase B (TrkB) expressions in the hypothyroidism-induced rat pups. These results suggest that treadmill exercise has beneficial effects in terms of protecting against thyroid dysfunction by increasing T3 and T4 and the related protein, BDNF, as well as TrkB, inhibition on astrocyte activation and the reduction of Purkinje cell loss regarding the cerebellum in hypothyroidism rat pups.

• The korean journal of orthodontics
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• v.30 no.4 s.81
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• pp.413-421
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• 2000

The purpose of this study was to observe the effects of pregnancy on the experimental tooth movement and alveolar bone turnover process of Sprague-Dawley female rat. Sixty rats were divided into pregnant-tooth movement group(P-Tm), normal-tooth movement group(N-Tm) and normal group(N). Maxillary first molar appliances were inserted bilaterally and activated to 40grams. To measure the amount of tooth movement, x-ray was taken 2 times after appliance insertion and before sacrifice. Animals were sacrificed at 1,3,7,14 days(N=5). Just after sacrifice, alveolar bones were collected and frozen immediately for biochemical analysis. Tooth movement was assessed cephalometrically and tartrate-resistant acid(TRAP) and alkaline phosphatase (ALP) activities were measured in extracts of paradental alveolar bone. The results were as follows: 1. The amount of tooth movement in P-Tm group was greater than that of N-Tm group(p<0.01). 2. Alveolar bone ALP of normal tooth movement group was not significantly different from the control, TRAP was significantly different from the control(p<0.01). In normal tooth movement group, alveolar bone ALP was increased gradually and peak(day 7) fell off significantly at day 14(p<0.05). The Peak of alveolar bone TRAP(day 7) fell off slightly, sustained day 14(p<0.01). 3. Alveolar bone ALP and TRAP of pregnant tooth movement group were not significantly different from that of normal tooth movement group. In pregnant tooth movement group, alveolar bone ALP was increased at day 3(p<0.01) and fell off significantly at day 7-14, alveolar bone TRAP were increased at day 3 and sustained day 14. 4. The peak of alveolar bone phosphatases in pregnant tooth movement group(day3) preceded the peak in normal tooth movement group(day7) (p<0.01). According to the above results, we suggested that bone resorption activity was increased in alveolar bone of pregnant rat, and the degree of tooth movement in pregnancy may be greater than that of normal group because of high bone turnover of alveolar bone in pregnant rat.

• Journal of Environmental Health Sciences
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• v.46 no.4
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• pp.368-375
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• 2020

Objectives: Some animal studies have reported that methyl mercury causes developmental toxicities such as placental and fetal weight loss, but the mechanism is still unclear. This study aimed to investigate the developmental toxicities of methyl mercury, focusing on placental endocrine function and fetal growth retardation in rats. Methods: Positively same-time-mated female Sprague-Dawley rats were purchased on gestational day (GD) eight and treated with 0, 5, 10 and 20 ppm of methyl mercury (n=5) dissolved in tap water from GD eight through 19. During treatment, the drinking water (methyl mercury) intake and body weight of each pregnant rat was measured daily. On day 19, caesarean sections were performed and blood samples were collected. Developmental data such as placental and fetal weights, fetus numbers, and placental efficiency (fetal weight/placental weight) were also collected. Placental prolactin-growth hormone (PRL-GH) family, such as placental lactogen (PL) -Iv, II, and prolactin-like protein (PLP) -B, levels in serum were analyzed by ELISA. Also, placental tissues were assigned to histochemistry. Results: The mean cumulative methyl mercury exposure for the 5, 10, and 20 ppm groups were 2.37, 4.63, and 9.66 mg, respectively. The mean daily exposure of the 5, 10, and 20 ppm groups were 0.24, 0.47, and 0.97 mg, respectively. Maternal body weight increased in accordance with GD. There was no significant difference in weight gain among the experimental groups. Histopathologic changes were not observed in placental tissues among the experimental groups. However, mean placental and fetal weights were lower in the 10 and 20 ppm exposed groups compared to the control. Placental efficiency was also lower in the 10 and 20 ppm exposed groups compared to the control. Serum PL-Iv and II levels were lower in the 10 and 20 ppm exposed groups than the control, in accordance with the changing pattern of placental and fetal weights and placental efficiency. Conclusion: The inhibitory effects of methyl mercury on the serum levels of placental PRL-GH family such as PL-Iv and II may be secondary leads to the reduction of placental efficiency and fetal growth retardation in rats.

• Biomolecules & Therapeutics
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• v.6 no.1
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• pp.73-81
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• 1998

Pregnant Sprague-Dawley rats were administered with Q-35 at the dose levels of 0, 30, 100 and 300 mg/kg/day by oral gavage from gestation day 17 to lactation period. Effects of the test chemical on general findings, reproductive performance of dams and development of Fl generation were examined. There were no treatment related changes in physical signs, body weight, necropsy findings, organ weights, delivery and nursing behavior. In 100 and 300 mg/fg/day treated groups, the food consumption of dams was decreased significantly during gestational day 19~21. The gestation length of 300 mg/tg/day treated group was increased significantly compared to the control group (22.3 $\pm$0.48 vs 22.0$\pm$0.39). Although the gestational length of all groups were in normal range of the rat, potential effect of the drug could not be ruled out. External anomaly of Fl fetus induced by Q-35 was not detected in any groups. There were no treaoent related changes in physical development, reflex functions, sensory functions, locomotor activity and motor coordinating activity. Estrus cycle, fertility and reproductive performance of Fl were not changed in all treated groups. There was no external abnormality related to the drug administration on the examination of F2. These results suggest that Q-35 has no adverse effect on the peri- and postnatal period in rats except the reduction of food consumption at the beginning of drug administration and the potential effect on the elongation of gestation length.

• Korean Journal of Veterinary Research
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• v.31 no.4
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• pp.419-424
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• 1991

This study was carried out to investigate; the alpha-fetoprotein, urea and free fatty acid in amniotic fluids and water filled multiple T-maze test of fetuses affected by Ethylenethiourea. The S.P.F. Sprague-Dawley female rats(10 weeks) were used in this study and these animals were divided into four groups; control group I (10mg/kg/day), group II(30mg/kg/day), group III(50mg/kg/day). The results obtained were summarized as follows; 1. In the water filled multiple T-maze test of F1 male rats, The time and errors from start point to goal point of 30mg/kg group are significantly(p<0.001) increased from control group in 3rd day of test. In F1 female rats of 2nd day and 3rd day of water filled multiple T-maze test, The time and some errors in 30mg/kg group are significantly (p<0.05) increased from control group. 2. Alpha-fetoprotein values of all treated groups(10mg/kg, 30mg/kg and 50mg/kg) were significantly(p<0.001) decreased from control values in the amniotic fluids. 3. Urea values of ammniotic fluids in 50mg/kg group are significantly increased from control group. 4. Free fatty acid values of ammniotic fluids in 50mg/kg group are significantly increased from control group.

• The Journal of Korean Medicine
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• v.24 no.3
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• pp.11-22
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• 2003

Objective : As the average span of human life extends, more and more people are at risk of developing osteoporosis, one of the typical diseases of the aged. This thesis presents the effects of Jeungikgwiryon-tang (Tsengikueijung-tang) on bone density, bone biochemical markers, and fetal calvarial cells (FCC) of Sprague Dawleys (S.D.) rats that have induced osteoporosis. The purpose is to see how Jeungikgwiryon-tang (Tsengikueijung-tang) reduces osteoporosis symptoms. Methods : In the first experiment Sprague Dawleys rats were administered Jeungikgwiryon-tang (Tsengikueijung-tang) for 70 days, once a day. Two different doses were used, creating high-dosed and low-dosed groups. The results were compared with a control group. In the second experiment, Jeungikgwiryon-tang (Tsengikueijung-tang) was applied to fetal calvarial cells (FCC) obtained from fetuses inside pregnant Sprague Dawleys rats. The FCCs from high-dosed and low-dosed groups were compared with those from a control group. Results : 1. Bone densities in Groups A and B increased significantly from a control group. 2. Bone ash densities in Group A showed substantial increase. 3. Calcium and phosphorus in bones in Group A increased significantly. 4. Activity of fetal calvarial cells' division in Groups A and B increased significantly from a control group, and ALP of fetal calvarial cells' formation in Group A increased significantly. 5. Protein and collagen levels of fetal calvarial cells in Group A increased significantly. Conclusion : It was found that Jeungikgwiryon-tang (Tsengikueijung-tang) has a tendency to make significant increases in bone densities by enhancing bone formation and by retarding bone absorption. It was concluded that Jeungikgwiryon-tang (Tsengikueijung-tang) activates osteoblast cells effectively.

• YAKHAK HOEJI
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• v.42 no.5
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• pp.534-539
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• 1998

Effect of recombinant human epidermal growth factor (rhEGF, DWP401) on fetal external, visceral and skeletal malformation during organogenesis was examined. Pregnant Sprauge-Daw ley rats were administered with 0.2, 1 and 5mg/kg/day subcutaneously on gestation day 6 through 16. Dams were sacrified at 20th day of gestation. Materal body weight, food consumption and clinical observation were not changed. Significant dose-dependent increase of relative and absolute liver weight were observed in the treatment group, whereas other organ weights were not changed. Placental weight of 1 and 5mg/kg/day group and number of resorption in 5mg/kg/day treatment group were significantly increased. External and visceral malformation of fetuses were not observed with treatment. However, skeletal variations(increase of asymmetry sternebrae, decrease of dumb-bell and asymmetry sternbrae at 5mg/kg/day, and fused stemebrae at 5mg/kg/day) were observed. These results showed that rhEGF (DWP401) may not have embryo and/or fetal developmental toxicity effect in rats.

• Development and Reproduction
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• v.27 no.4
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• pp.195-203
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• 2023

Exposure to environmental chemicals, including endocrine-disrupting chemicals, during the gestational period can have profound adverse effects on several organs in offspring. Bisphenol A (BPA) can infiltrate the human body through food and drinks, and its metabolites can cross both the placental and the blood-brain barriers. In this study, we investigate the effect of gestational exposure to BPA on epigenetic, biochemical, and histological modifications in the uterine tissues of F1 adult offspring rats. Pregnant rats were exposed to BPA from gestational day 8-15, and changes in global DNA methylation in uterine tissues obtained from adult offspring born to the exposed mothers were analyzed. Global DNA methylation analysis revealed that gestational exposure to BPA resulted in DNA hypomethylation in the uterus. Progesterone receptor (PR) protein expression in uterine tissues was monitored using western blot analysis, which revealed that the PR protein content was considerably higher in all BPA-exposed groups than in the control. Immunohistochemical examination for the PR revealed that intense PR-positive cells were more frequently observed in the BPA-exposed group than in the control group. To date, the evidence that the upregulation of PRs observed in the present study was caused by the non-methylation of specific PR promoter regions is lacking. Conclusively, these results indicate that exposure to BPA during gestation induces epigenetic alterations in the uteri of adult female offspring. We speculate that the global DNA hypomethylation and upregulation of the PR observed simultaneously in this study might be associated with the uterus.

• Biomolecules & Therapeutics
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• v.3 no.1
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• pp.38-46
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• 1995

DA-125, a new anthracycline antitumor antibiotic, was administered at dose levels of 0, 0.04, 0.2 and 1.0 mg/kg/day intravenously to pregnant and subsequently delivered Sprague-Dawley rats from day 17 of gestation to day 21 of lactation. Effects of test agent on general toxicity of dams and growth, behaviour and mating performance of F1 offspring were examined. At 1 mg/kg, one out of the twentytwo dams showed difficult delivery, characterized by a stillbirth. Reduction in body weight, loss in food intake, and decrease in spleen weight were also observed in dams. In addition, the lower rates of successful performances in memory test (28.6%) and necrosis of tail end (9.5%) were seen in F1 offspring. At 0.04 and 0.2 mg/kg, no toxic effect on dams and F1 offspring was observed. There were no malformed Fl and F2 fetuses in all groups. The results indicate that the no effect dose levels(NOELs) of DA-125 are 0.2 mg/kg/day for dams and Fl offspring, and over 1 mg/kg/day for F2 fetuses.

• Toxicological Research
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• v.3 no.1
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• pp.45-53
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• 1987

A teratogenicity study was carried out on Sprague-Dawley rats which have been given the intravenously or intraperitonealy injections of rHuIFN-${\alpha}$A, an available therapeutic agent, at dose levels of $1{\times}10^5$, $4{\times}10^5$ and $1.2{\times}10^6$ I.U/kg/day for a period of 11 days from day 7 to day 17 of gestation. Two-thirds of the pregnant females in each group were sacrificed on day 20 of gestation and their fetuses were examined. The remaining dams were allowed to litter naturally, and the postnatal development of the off springs was observed. No changes were observed in all aspects of parameters between the treated and the control dams. The incidence of external, internal, and skeletal anomalies were not significantly increased in the fetuses of any treated groups. The rHuIFN-${\alpha}A$ caused no effects on parturition, lactation, and postnatal growth.