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Prenatal interactive effects of hyperthermia and diabetes on mouse fetus
212
Poster Session 4C. Reproductive Toxicology
phthalate is the major metabolite in mice urine but is absent in rat urine. The other major DEHP metabolites (metabolites I and V from w-oxidation and ,a-oxidation and metabolites VI and IX from w-l oxidation) were mainly excreted via the urine of both species, and no qualitative differences were observed between pregnant and nonpregnant animals. In rats, the major metabolites are VI and IX. Phase II metabolites were also identified in mouse urine, nevertheless the activity glucuronide pathway decreased over the treatment. In both species, the metabolism rate seems slightly greater in pregnant than in non-pregnant animals. In all cases, DEHP was identified in faeces and was absent in urine, suggesting that a large part of DEHP was not absorbed. In conclusion, the results suggest that the difference in species-sensitivity to the developmental toxicity could be related with differences in metabolism.
I P4C43!
THE ENHANCEMENT OF DIABETES TERATOGENICITY BY MATERNAL RESTRAINT STRESSIN THE MOUSE
M. Salazar *, D. Hernandez, G. Brenes, S. Salazar. Departamento de Toxicologia; Escuela Nacional de Ciencias Biologicas, lnstituto Politecnico Nacional, Mexico D.F., Mexico Diabetes and maternal stress, respectively, is known to induce several developmental toxicity in experimental animals. These factors, in combination with known teratogenic agents has been shown to increase the teratogenicity of such agents. It has been well established that diabetic pregnant women may be exposed to various types of stress in different places. Thus it is of interest to determine whether simultaneously exposing pregnant females to diabetes and stress, enhances, the production of toxic effects in the developing offspring. Six treatment groups were used: control (C), diabetes (D), food/water-deprived (FWD), restraint only (R), diabetes + food/water deprive (D + FWD) and diabetes + restraint (D + R). Diabetes was induced by administration of streptozotocin on day 7 of gestation and restriction was applied during 12 h on day 9, by supine position of animals. FWD group mice were deprived of food and water during the same time period. All animals were sacrificed on day 19 of gestation and fetuses were subjected to teratological evaluation. The results show that maternal stress strengthened the embryotoxicity of diabetes which was reflected in embryonic mortality, decreasing degree of ossification, as well as in a qualitative increase in the severity of the skeletal malformations. It is suggested that stress during pregnancy, combined with uncontrolled diabetes, may result in an enhancement of prenatal toxicity to the progeny. Such results may aid our understanding of the role that maternally mediated effects can have in affecting developmental outcome.
IP4C44 I PRENATAL INTERACTIVE EFFECTS OF HYPERTHERMIA AND DIABETES ON MOUSE FETUS
G. Chamorro *, G. Brenes, D. Hernandez. Departamento de Toxicologic, Escuela Nacional de Ciencias Biologicas, lnstituto Politecnico Nacional, Mexico D.F., Mexico Hyperthermia appears to be capable of causing congenital defects in all species and may act alone or synergistically with some chemicals. On the other hand, experiments in rodents systems have demonstrated also a higher incidence of morphological abnormalities in embryos obtained from diabetic pregnancies (l). In the present study, we have investigated whether the diabetic prenatal state enhances the teratogenicity of hyperthermia in mice. Pregnant mice were divided into eleven groups: diabetic (D), hyperthermia 39°C (H39), 40°C (H40), 41°C (H4l), 42°C (H42), 43°C H43), D + H39, D + H40, D + H41, D + H42, and D + H43. Diabetes was induced by administration of streptozotozin on day 7 of gestation, and hyperthermia, on day 8 for 10 minutes, by partial immersion of animals in water at the
desired temperature. Another group of mice treated at 37°C was used as control. All animals were killed on day 19 of gestation and fetuses were examined for external and internal abnormalities. Animals of groups D + H41-D + H43, lost significantly more weight than the concurrent controls. Significant increases in embryo/fetal mortality were observed in the offspring of groups D + H40 and D + H43, although in D + H41 a protective effect was observed. Incidences of visceral malforma-tions were found in D + H41 and D + H42, but no in D + H43. It is concluded that hyperthermia potentiates the teratogenic effects of maternal diabetes, although a thermotolerance phenomen can be produced to some temperatures. [1] Lin, Y. et al., (1995). Teratogen. Carcin. Mut. 15: 147-153.
HISTOLOGICAL ALTERATIONS IN THE XENOPUS IP4C45 I LARVAE EXPOSED TO 2,3,7,8-TETRACHLORODIBENZo-P-DIOXIN (TeDD) AT EMBRYONIC AND EARLY LARVAL STAGES
Shin Mima *, Michiko Sakamoto, Takashi Tanimura. Department of Anatomy, Kinki University School ofMedicine, Osaka, Japan We previously reported that TCDD causes death, edema and the growth retardation in Xenopus larvae. The present study was to examine histological alterations of Xenopus larvae at 12 days after fertilization. Xenopus embryos were continuously exposed to 200 ppb of TCDD for 5 days from day 0-5 after fertilization. The larvae were histologically examined using 10 uii: paraffin and I {tm Epon sections. In the TCDD group, contents in esophagus, stomach and intestine were markedly reduced. Edema was noted in the ocular region, in the subcutaneous layer, between the muscular layer and serosa of thoracoabdominal wall, and in the submucous layer of digestive organs. The ascites in abdomen were also observed. Submucosal vessels were markedly dilated in the digestive tract. Various degrees of degenerative epithelia were often observed in the lumen of the digestive tract, particularly numerous in the duodenum. The disturbance of the reticular structure of hepatic parenchymal cells and sinusoidal capillaries was observed in the exposed group. The results suggest that the histological alterations in the digestive and circulatory systems induced by TCDD are one of the causes of edema formation and death of the exposed larvae.
I P4C46 I DEVELOPMENTAL TOXICITY EVALUATION OF N-METHYLDIETHANOLAMINE (MDEA) APPLIED CUTANEOUSLY TO CD® RATS
H.-W. Leung *, B. Ballantyne. Applied Toxicology Group, Union Carbide Corporation, Danbury, CT, USA Aqueous N-methyldiethanolamine (MDEA) was applied cutaneously (6 hr/day) to pregnant CD® rats from gestation day (gd) 6-15, inclusive. Doses employed were 0, 250, 500 and 1000 mglkg/day and were selected on the basis of toxicity responses determined from range finding studies on pregnant rats. Monitors for maternal toxicity included body weight and food consumption measurements, and clinical observations including skin irritation scores. Prior to scheduled necropsy on gd 21, blood was obtained from dams for hematologic measurements. At necropsy, liver and kidney, which are putative target organs, were weighed. Fetuses were evaluated for body weight and for external, visceral and skeletal anomalies. Severe skin irritation, characterized by necrosis, ecchymoses, erythema, edema, exfoliation, crusting and excoriation, were noted in dams receiving 1000 tug/kg/day during the dosing period and persisted for several days subsequent to treatment. However, by gd 21, substantial repair of the dosing site had occurred. Less severe skin irritation was noted at 500 rug/kg/day, There were no effects of treatment on maternal body weight, gestational weight gain or food consumption. Maternal liver or kidney weights were also unaffected. Mild anemia
Poster Session 4C. Reproductive Toxicology
phthalate is the major metabolite in mice urine but is absent in rat urine. The other major DEHP metabolites (metabolites I and V from w-oxidation and ,a-oxidation and metabolites VI and IX from w-l oxidation) were mainly excreted via the urine of both species, and no qualitative differences were observed between pregnant and nonpregnant animals. In rats, the major metabolites are VI and IX. Phase II metabolites were also identified in mouse urine, nevertheless the activity glucuronide pathway decreased over the treatment. In both species, the metabolism rate seems slightly greater in pregnant than in non-pregnant animals. In all cases, DEHP was identified in faeces and was absent in urine, suggesting that a large part of DEHP was not absorbed. In conclusion, the results suggest that the difference in species-sensitivity to the developmental toxicity could be related with differences in metabolism.
I P4C43!
THE ENHANCEMENT OF DIABETES TERATOGENICITY BY MATERNAL RESTRAINT STRESSIN THE MOUSE
M. Salazar *, D. Hernandez, G. Brenes, S. Salazar. Departamento de Toxicologia; Escuela Nacional de Ciencias Biologicas, lnstituto Politecnico Nacional, Mexico D.F., Mexico Diabetes and maternal stress, respectively, is known to induce several developmental toxicity in experimental animals. These factors, in combination with known teratogenic agents has been shown to increase the teratogenicity of such agents. It has been well established that diabetic pregnant women may be exposed to various types of stress in different places. Thus it is of interest to determine whether simultaneously exposing pregnant females to diabetes and stress, enhances, the production of toxic effects in the developing offspring. Six treatment groups were used: control (C), diabetes (D), food/water-deprived (FWD), restraint only (R), diabetes + food/water deprive (D + FWD) and diabetes + restraint (D + R). Diabetes was induced by administration of streptozotocin on day 7 of gestation and restriction was applied during 12 h on day 9, by supine position of animals. FWD group mice were deprived of food and water during the same time period. All animals were sacrificed on day 19 of gestation and fetuses were subjected to teratological evaluation. The results show that maternal stress strengthened the embryotoxicity of diabetes which was reflected in embryonic mortality, decreasing degree of ossification, as well as in a qualitative increase in the severity of the skeletal malformations. It is suggested that stress during pregnancy, combined with uncontrolled diabetes, may result in an enhancement of prenatal toxicity to the progeny. Such results may aid our understanding of the role that maternally mediated effects can have in affecting developmental outcome.
IP4C44 I PRENATAL INTERACTIVE EFFECTS OF HYPERTHERMIA AND DIABETES ON MOUSE FETUS
G. Chamorro *, G. Brenes, D. Hernandez. Departamento de Toxicologic, Escuela Nacional de Ciencias Biologicas, lnstituto Politecnico Nacional, Mexico D.F., Mexico Hyperthermia appears to be capable of causing congenital defects in all species and may act alone or synergistically with some chemicals. On the other hand, experiments in rodents systems have demonstrated also a higher incidence of morphological abnormalities in embryos obtained from diabetic pregnancies (l). In the present study, we have investigated whether the diabetic prenatal state enhances the teratogenicity of hyperthermia in mice. Pregnant mice were divided into eleven groups: diabetic (D), hyperthermia 39°C (H39), 40°C (H40), 41°C (H4l), 42°C (H42), 43°C H43), D + H39, D + H40, D + H41, D + H42, and D + H43. Diabetes was induced by administration of streptozotozin on day 7 of gestation, and hyperthermia, on day 8 for 10 minutes, by partial immersion of animals in water at the
desired temperature. Another group of mice treated at 37°C was used as control. All animals were killed on day 19 of gestation and fetuses were examined for external and internal abnormalities. Animals of groups D + H41-D + H43, lost significantly more weight than the concurrent controls. Significant increases in embryo/fetal mortality were observed in the offspring of groups D + H40 and D + H43, although in D + H41 a protective effect was observed. Incidences of visceral malforma-tions were found in D + H41 and D + H42, but no in D + H43. It is concluded that hyperthermia potentiates the teratogenic effects of maternal diabetes, although a thermotolerance phenomen can be produced to some temperatures. [1] Lin, Y. et al., (1995). Teratogen. Carcin. Mut. 15: 147-153.
HISTOLOGICAL ALTERATIONS IN THE XENOPUS IP4C45 I LARVAE EXPOSED TO 2,3,7,8-TETRACHLORODIBENZo-P-DIOXIN (TeDD) AT EMBRYONIC AND EARLY LARVAL STAGES
Shin Mima *, Michiko Sakamoto, Takashi Tanimura. Department of Anatomy, Kinki University School ofMedicine, Osaka, Japan We previously reported that TCDD causes death, edema and the growth retardation in Xenopus larvae. The present study was to examine histological alterations of Xenopus larvae at 12 days after fertilization. Xenopus embryos were continuously exposed to 200 ppb of TCDD for 5 days from day 0-5 after fertilization. The larvae were histologically examined using 10 uii: paraffin and I {tm Epon sections. In the TCDD group, contents in esophagus, stomach and intestine were markedly reduced. Edema was noted in the ocular region, in the subcutaneous layer, between the muscular layer and serosa of thoracoabdominal wall, and in the submucous layer of digestive organs. The ascites in abdomen were also observed. Submucosal vessels were markedly dilated in the digestive tract. Various degrees of degenerative epithelia were often observed in the lumen of the digestive tract, particularly numerous in the duodenum. The disturbance of the reticular structure of hepatic parenchymal cells and sinusoidal capillaries was observed in the exposed group. The results suggest that the histological alterations in the digestive and circulatory systems induced by TCDD are one of the causes of edema formation and death of the exposed larvae.
I P4C46 I DEVELOPMENTAL TOXICITY EVALUATION OF N-METHYLDIETHANOLAMINE (MDEA) APPLIED CUTANEOUSLY TO CD® RATS
H.-W. Leung *, B. Ballantyne. Applied Toxicology Group, Union Carbide Corporation, Danbury, CT, USA Aqueous N-methyldiethanolamine (MDEA) was applied cutaneously (6 hr/day) to pregnant CD® rats from gestation day (gd) 6-15, inclusive. Doses employed were 0, 250, 500 and 1000 mglkg/day and were selected on the basis of toxicity responses determined from range finding studies on pregnant rats. Monitors for maternal toxicity included body weight and food consumption measurements, and clinical observations including skin irritation scores. Prior to scheduled necropsy on gd 21, blood was obtained from dams for hematologic measurements. At necropsy, liver and kidney, which are putative target organs, were weighed. Fetuses were evaluated for body weight and for external, visceral and skeletal anomalies. Severe skin irritation, characterized by necrosis, ecchymoses, erythema, edema, exfoliation, crusting and excoriation, were noted in dams receiving 1000 tug/kg/day during the dosing period and persisted for several days subsequent to treatment. However, by gd 21, substantial repair of the dosing site had occurred. Less severe skin irritation was noted at 500 rug/kg/day, There were no effects of treatment on maternal body weight, gestational weight gain or food consumption. Maternal liver or kidney weights were also unaffected. Mild anemia