• Toxicological Research
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• v.35 no.4
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• pp.343-351
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• 2019

Many in vitro developmental toxicity assays have been proposed over several decades. Since the late 1980s, we have made intermittent attempts to introduce in vitro assays as screening tests for developmental toxicity of inhouse candidate products. Two cell-based assays which were developed two decades apart were intensively studied. One was an assay of inhibitory effects on mouse ascites tumor cell attachment to a concanavalin A-coated plastic sheet surface (MOT assay), which we studied in the early days of assay development. The other was an assay of inhibitory effects on the differentiation of mouse embryonic stem cell to beating heart cells (EST assay), which we assessed more recently. We evaluated the suitability of the assays for screening in-house candidates. The concordance rates with in vivo developmental toxicity were at the 60% level. The EST assay classified chemicals that inhibited cell proliferation as embryo-toxic. Both assays had a significant false positive rate. The assays were generally considered unsuitable for screening the developmental toxicity of our candidate compounds. Recent test systems adopt advanced technologies. Despite such evolution of materials and methods, the concordance rates of the EST and MOT systems were similar. This may suggest that the fundamental predictivity of in vitro developmental toxicity assays has remained basically unchanged for decades. To improve their predictivity, in vitro developmental toxicity assays should be strictly based on elucidated pathogenetic mechanisms of developmental toxicity.

• Toxicological Research
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• v.17 no.3
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• pp.225-234
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• 2001

The present study was conducted to investigate the effects of Korean red ginseng water extract (KRGWE) on developmental toxicity caused by the environmental estrogen bisphenol A (BPA) in Sprague-Dawley rats. fifty males successfully mated were randomly assigned to five experimental groups, 1.e., group I (vehicle control), group II (BPA 1000mg/kg), group III (KRGWE 400mg/kg), group IV (BPA 1000mg/kg & KRGWE 200mg/kg), and group V (BPA 1000mg/kg & KRGWE 400mg/kg). The test articles were administered by gavage to mated females from gestational days (GD) 1 through 20 (sperm vaginal lavage=day O). All females were subjected to caesarean section on GD 21 and their fetuses were examined for external, visceral, and skeletal abnormalities. In the group II, significant maternal toxic effects including suppressed body weight, decreased body weight gain during pregnancy, and reduced food consumption were observed in pregnant rats. The minimal developmental toxicity including fetal ossification delay was also found in fetuses. In addition, a tendency for increased pregnancy failure, increased pre-and postimplantation loss, and decreased fetal body weight was observed. However, no fetal morpho-logical abnormalities were seen in surviving fetuses at a dose level of 1000mg BPA/kg. On the other hand, the maternal toxicity and developmental toxicity found in the groups IV and V were comparable to those of the group II. There were no adverse signs of either maternal toxicity or developmental toxicity in the group III. These results showed that administration of BPA at a dose level of 1000mg/kg to pregnant rats resulted in significant maternal toxicity and minimal developmental toxicity, and that no protective effects on BPA-induced maternal toxicity and developmental toxicity were found by concomitant gavage dosing of KRGWE.

• Journal of Environmental Health Sciences
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• v.44 no.5
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• pp.468-479
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• 2018

Objectives: Recently, a report was published that the humidifier disinfectant CMIT/MIT did not cause developmental toxicity and was not detected in systemic circulation as a result of an inhalation toxicity test. Therefore, this study was carried out to investigate any associations between CMIT/MIT exposure and developmental toxicity using the in vivo apical toxicity test method. Methods: Groups of pregnant ICR mice were instilled in the trachea with chloromethylisothiazolinone/methylisothiazolinone (CMIT/MIT) using a visual instillobot over a period of seven days from days 11 to 17 days post-coitum. For the in vivo apical toxicity test method, an $LD_{50}$-based dose-range finding model was applied to decide the dose range for inducing developmental toxicity. Results: Among the groups of 0, 0.1, 0.5, 1.0, and 1.5 mg ai/kg/day CMIT/MIT, the exposure groups of 0.5 mg and 1.0 ai/kg/day CMIT/MIT were estimated to reflect the thresholds for the stillbirth and death of pregnant mice, respectively. The groups of 0.5, 1.0, and 1.5 mg ai/kg/day CMIT/MIT induced stillbirth rates of 2.57, 10, and 53.8%, respectively. Another exposure group of 0.75 mg ai/kg/day CMIT/MIT did not induce any deaths of pregnant mice and resulted in a stillbirth rate of 8% in only one of six pregnant mice. Conclusions: CMIT/MIT can induce stillbirth in pregnant mice. It was also concluded that CMIT/MIT moves through the pulmonary circulation system and then continues on through systemic circulation and the placenta. There is a possibility of stillbirth and other health causalities in humans beyond the lungs caused by CMIT/MIT exposure.

• Toxicological Research
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• v.29 no.4
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• pp.221-227
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• 2013

Embryonic stem (ES) cells have potential for use in evaluation of developmental toxicity because they are generated in large numbers and differentiate into three germ layers following formation of embryoid bodies (EBs). In earlier study, embryonic stem cell test (EST) was established for assessment of the embryotoxic potential of compounds. Using EBs indicating the onset of differentiation of mouse ES cells, many toxicologists have refined the developmental toxicity of a variety of compounds. However, due to some limitation of the EST method resulting from species-specific differences between humans and mouse, it is an incomplete approach. In this regard, we examined the effects of several developmental toxic chemicals on formation of EBs using human ES cells. Although human ES cells are fastidious in culture and differentiation, we concluded that the relevancy of our experimental method is more accurate than that of EST using mouse ES cells. These types of studies could extend our understanding of how human ES cells could be used for monitoring developmental toxicity and its relevance in relation to its differentiation progress. In addition, this concept will be used as a model system for screening for developmental toxicity of various chemicals. This article might update new information about the usage of embryonic stem cells in the context of their possible ability in the toxicological fields.

• Toxicological Research
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• v.26 no.1
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• pp.67-74
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• 2010

The present study was conducted to obtain information on the effects of amitraz on reproductive and developmental parameters in rats. The test chemical was administered via the drinking water containing 0, 40, 120, and 360 ppm to male rats from 2 weeks before mating to the end of 14-day mating period and to females from 2 weeks before mating, throughout mating, gestation and up to lactational day 4. During the study period, clinical signs, body weights, food intake, organ weights, reproductive and littering findings, necropsy findings, sperm parameters, and histopathology were examined. At 360 ppm, decreases in the body weight gain, food consumption, and the number of live pups and an increase in the post-implantation loss were observed. In addition, decreases in the seminal vesicle weight and sperm motility were found in males. At 120 ppm, a decrease in the food consumption was found transiently in both males and females, but no reproductive and developmental toxicity was observed in both sexes. There were no signs of either general or reproductive and developmental toxicity in the 40 ppm group. Based on these results, it was concluded that the repeated oral administration of amitraz to rats resulted in a decrease in the food consumption at 120 ppm and decreases in the seminal vesicle weight, sperm motility, and the number of live pups and an increase in the post-implantation loss at 360 ppm in rats. Under these experimental conditions, the no-observed-adverse-effect level (NOAEL) of amitraz for general and reproduction/developmental toxicity was believed to be 120 ppm, and the no-observed-effect level (NOEL) of amitraz was believed to be 40 ppm in rats.

• Toxicological Research
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• v.19 no.4
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• pp.267-275
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• 2003

The purpose of our study was to evaluate the toxicity of the thimerosal in embryos and neonates. Thimerosal (also known as mercurothiolate) is a mercury-containing compound used in trace amounts to prevent bacteria and other organisms from contaminating vaccines, especially in opened multi-dose vials. The toxicity of mercury is well known and those most at risk occurrs in unborn babies and newborn babies. Test methods included in vitro whole embryo culture (WEC) system and in vivo test of neonatal toxicity in Wistar rats. Ethylmercury and methylmercury were used as positive controls for the evaluating of toxic effects of mercury. In WEC assay, treated concentrations of thimerosal, ethylmercury and methylmercury were up to 0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 1, 2.5 and 5 $\mu\textrm{g}$/$\textrm{m}{\ell}$, respectively. All compounds didn't show any morphological abnormalities, but showed retardation of growth and development in dose dependent manner (> 0.5 $\mu\textrm{g}$/$\textrm{m}{\ell}$). These data indicated that thimerosal showed developmental toxicity in vitro. In vivo neonatal toxicity, Wistar rats were administered subcutaneously with thimerosal, ethyl mercury, or methylmercury (5, 25, 50, 250, and 500 $\mu\textrm{g}$/kg) during from postnatal day (PND) 4 to 25. Significant effects of these compounds on relative organ weights and organ morphology were not observed in this experiment. However, accumulation of mercury was detected in the kidney and testis when treated with thimerosal, ethylmercury, or methylmercury. These results suggest that thimerosal may be a harmful compound to embryo and neonate, but used concentration of thimerosal in these experiments is much higher than that of clinical application. Further investigation is needed on the safety of vaccine components, i.e. a thimerosal using in vitro and in vivo tests in the future.

• Environmental Analysis Health and Toxicology
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• v.25 no.3
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• pp.241-251
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• 2010

Crucian carp (Carassius auratus) has been used as the sentinel species for POPs (Persistent Organic Pollutants) monitoring in aquatic environment. However, there is little information for dioxin toxicity and especially, early life stage toxicity in crucian carp have been never carried out. In this study, we investigated several toxic effects for 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) in fertilized egg obtained by natural fertilization from crucian carp. The embryos at 3 h post-fertilization (hpf) were treated with 0.039, 0.156, 0.625, and 2.5 (${\mu}g/L$) TCDD by waterborne exposure for 60 minutes and changed with fresh water 2 times per day. Fertilized eggs started hatching at 51 hpf and TCDD exposed embryo showed decrease of hatching rate in a dose-dependent manner at 75 hpf. Pericardial edema was continuously observed in larvae exposed to TCDD from hatching start time (51 hpf), followed by the onset of mortality. In addition, AhR-related gene, CYP1A was clearly increased by TCDD in a dose dependent manner. These results indicated that fertilized eggs obtained from crucian carp have the TCDD related gene regulation and a distinct TCDD developmental toxicity syndrome by TCDD exposure. Therefore, we suggested that early life stage test in crucian carp could be used as test methods on dioxins toxicity.

• Biomolecules & Therapeutics
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• v.6 no.1
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• pp.82-88
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• 1998

LBO0014, a new recombinant human erythropoietin, was at dose levels of 0, 120, 600, and 3,000 IU/kg/day administered intravenously to pregnant Sprague-Dawley rats during the organogenetic period. All dams were subjected to caesarean section on day 20 of pregnancy, Effects of test substance on dams and embryonic development of Fl fetuses were examined. No treatment-related changes in clinical signs, body weight, and food consumption were observed at all doses tested. At necropsy spleen enlargement was found at 3,000 lU/kg. There was an ulcrease in the spleen weight at 600 and 3,0007/kg. Developmental toxicity was evident as increased resorptions at 3,000 lU/kg. At 600 and 3,000 RJ/kg, retarded ossification of fetuses occurred at an incidence of 31.3% and 64.7%, respectively. In addition, there was a delay in ossification of sternebrae and sacrocaudal vertebrae at 600 and 3,000 lU/kg. A decrease in the number of metacarpi and metatarsi was also seen at 3,000 nJ/kg. The results show that the no observed adverse effect dose level (NOAEL) for material toxicity was over 3,000 IU/kg/day and the NOAEL for developmental toxicity was 120 IU/kg/day.

• Journal of Ginseng Research
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• v.43 no.2
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• pp.242-251
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• 2019

Background: Korean Red Ginseng has been widely used in traditional oriental medicine for a prolonged period, and its pharmacological effects have been extensively investigated. In addition, Angelica gigas and deer antlers were also used as a tonic medicine with Korean Red Ginseng as the oriental herbal therapy. Methods: This study was conducted to evaluate the potential toxicological effect of KGC-HJ3, Korean Red Ginseng with angelica gigas and deer antlers, on reproductive and developmental functions including fertility, early embryonic development, maternal function, and embryo-fetal development. KGC-HJ3 was administered by oral gavage to Sprague-Dawley rats (22 animals per sex per group) at dose levels of 0 mg/kg (control), 500 mg/kg, 1000 mg/kg, and 2000 mg/kg to evaluate the potential toxicological effect on fertility and early embryonic development. In addition, KGC-HJ3 was also administered by oral gavage to mating-proven Sprague-Dawley rats (22 females per group) during the major organogenesis period at dose levels of 0 mg/kg (control), 500 mg/kg, 1000 mg/kg, and 2000 mg/kg to evaluate the potential toxicological effect on maternal function and embryo-fetal development. Results and conclusion: No test item-related changes in parameters for fertility, early embryonic development, maternal function, and embryo-fetal development were observed during the study period. On the basis of these results, it was concluded that KGC-HJ3 did not have toxicological potential on developmental and reproductive functions. Therefore, no observed adverse effect levels of KGC-HJ3 for fertility, early embryonic development, maternal function, and embryo-fetal development is considered to be at least 2000 mg/kg/day.

• Korean Journal of Ecology and Environment
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• v.44 no.2
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• pp.103-112
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• 2011

Aquatic contamination by organic pollutants has been a suspected reason for rapid decrease of amphibian populations whose embryonic and larval stages are in an aquatic environment. Amphibian embryos can be a useful model to study the ecoctoxicologial impacts of aquatic pollutants. The obtained toxicological data are useful references for the management of aquatic pollutants in public health because amphibia share many developmental events with terrestrial vertebrates including humans. Safety guidelines for the toxicological effects of aquatic contaminants of chemicals identified as hazardous should be addressed at multiple endpoints. Alkylphenols have been widely-used in agricultural, industrial, and household activities; they contaminate and can persist in aquatic environments. Exposure to alkylphenols results in endocrine disruption in aquatic animals. In this review, we summarize the developmental toxicities of alkylphenols in amphibian embryos and larva according to the exposure route, chemical concentration, duration of exposure, and affected developmental stage together with mechanisms of toxicity and typical patterns of developmental abnormality. The merits of amphibian embryos as a toxicity test model for mid- to long-term exposure to aquatic pollutants are discussed proposed.