Embryotoxic Activity Research Articles

The toxicology of chemical interactions during pregnancy in the mouse: Caffeine and phenytoin

The toxic interaction of caffeine and phenytoin during pregnancy was investigated in mice of the ICR strain on E10 of gestation. Caffeine, over a range of dosages, showed limited embryotoxic activity. Phenytoin was also weakly teratogenic and dosages needed to elicit embryotoxicity were accompanied by a significant increase in maternal lethality. Pretreatment with caffeine enhanced phenytoin-induced toxicity and teratogenicity and these observations confirm that caffeine has the ability to function as a coteratogen. Pretreatment with phenytoin produced a significant increase in maternal lethality following caffeine administration but no co-teratogenic effect. It is suggested that these results are the consequence of a yet undefined interaction at critical receptor sites in the maternal-embryo unit.

Teratogenic activity of aliphatic and aromatic fractions of Prudhoe Bay crude and fuel oil No. 2 in the chicken embryo

The teratogenic and embryotoxic activities of aliphatic (fraction 1), two- or three-ring aromatic (fraction 3), and four- or five-ring aromatic (fraction 4) fractions of Prudhoe Bay crude oil and fuel oil No. 2 were investigated in the developing chicken embryo. Embryos were treated at 96 hr development via the air sac membrane. Treatment with the aliphatic fraction of either oil did not cause any increase in developmental abnormalities; however, it did result in a dose-related significant decrease in weight, crown-rump length, and head length. Fraction 3 of both oils had both teratogenic and embryotoxic activities in the embryos, causing aberrations such as gastroschisis, edema, beak abnormalities, hemorrhages, and limb defects. Fraction 4 of Prudhoe Bay crude caused a slight but insignificant increase in developmental abnormalities while fraction 4 of fuel oil No. 2 had no teratogenic effect at the concentrations tested.

Neuromuscular blocking agents and axial teratogenesis in the avian embryo. Can axial morphogenetic disorders be explained by pharmacological action upon muscle tissue?

A comparative qualitative and quantitative study of the embryotoxic and teratogenic activities of various chemical agents known to have neuromuscular blocking properties was done on the quail embryo. Intrinsic embryotoxic activity and teratogenicity were evaluated for each agent, and the qualitative nature of the teratogenic effects was correlated with the pharmacologic properties of the different effectors. Gross malformations (contorted posture) were found only with agents which directly (cholinergic agonists) or indirectly (cholinesterase inhibitors) favor muscle membrane depolarization, suggesting that such malformations may be due to muscle contraction following depolarization. All of the agents studied produced variable degrees of vertebral fusion, apparently due to paralysis resulting either from sustained depolarization (cholinesterase inhibitors and cholinergic agonists) or directly from cholinergic blockade (cholinergic antagonists and neurotoxins).

Cytotoxic effect of structurally modified bull seminal ribonuclease (AS RNase)

Chemical modifications of bull seminal ribonuclease (AS RNase) cause considerable changes in its cytotoxic activity. However, binding of AS RNase on cells has been changed little or not at all. Every modification (oxidation, reduction, carbomethylation, succinylation and maleylation) inhibited ribonuclease and aspermatogenic and embryotoxic activity of AS RNase. The common cytotoxic effect was also changed to some degree. Inhibition of incorporation of 3H-thymidine to BP-8 tumor cells in culture was observed after application of native, oxidized, reduced, and carboxymethylated AS RNase.

Formula omitted] study of the embryotoxic activity of leukocytes

The embryotoxic activity of polymorphonuclear leukocytes (PMNLs), macro-phages abd endometrial cells was studied in vivo. Rabbits were mated, both uterine horns were ligated at the cervical end, and different concentrations of intact or homogenized cells were injected in one horn while the other served as control. The fertility rate, size of implantations and number of cells in uterine flushings were assessed 10 days postcoitum. PMNLs, macrophages, and endometrial cells exhibited a potent antifertility effect, retarded post-implantation growth and attracted large numbers of white cells. A definite dose and effect relationship between the concentration of cells and the different parameters was demonstrated. Phagocytosis did not play a role in this system. The embryotoxic effect is not limited to uterine cells since it could also be demonstrated in liver, thyroid and red blood cells.

Induktion von Mißbildungen durch N-Methyl-N-nitrosoharnstoff (MNH)

After observing multiple malformations in a stillborn infant whose mother was in contact with MNU during pregnancy, the inhalation of evaporated MNU solution or diazomethane was regarded as a possible cause. An attempt was made to reproduce the same conditions in experiments with rats. Material and methods: The experiments were carried out with 46 pregnant rats yielding 370 fetuses. With the aid of an atomizer a solution of 50 mg MNU was atomized in a container of 12 liters. In each test up to 3 rats were exposed for 30 min (group Al). In other groups (B1–3) rats placed into the same container breathed diazomethane which was produced by dropping NaOH on MNU. During this experiment, rats were apathetic and their respiration was accelerated. In group C1–9, MNU was injected intraveneously or intraperitoneally. Animals which had no contact neither with complete MNU nor with its decomposition products served as control (group D1). Rats were killed at the 21st day of pregnancy. After laparotomy, fetuses were weighed and fixed in Bouin's solution or in ethanol. Fetuses were examined macroscopically. Afterwards the head and the trunk were dissected. In a number of cases the skeleton was stained with alizarin red S. Results: Malformations that affected the skeleton and the central nervous system could be found only in those experiments in which rats were exposed to the complete teratogenic agent. By means of external inspection microcephalia, micrognathia, cleft palate, micromelia, syn- and polydactylia, lordosis and skoliosis of the spinal column as well as deviations of the extremities were observed. Above this, by bone preparation by alizarin red S malformations of the skull (micrognathia, aplasia of the zygomatic bone) hypoplasia and deformations of the clavicula, scapula, ribs as well as of bones of the extremities were found. MNU led to complex malformations in the central nervous system comprising microencephalia, hydrocephalus as well as defects of the septum pellucidum and the corpus callosum. Frequency and spectrum of malformations depended on the dosage and the age of pregnancy. As the embryotoxic activity was relatively low at day 13 and as malformations were observed in all cases, this day proved to be the most effective one. In contrast to the application of MNU, after inhalation of diazomethane malformations did not occur. However, as a toxic effect a significant increase in dead fetuses and a reduction of the body weight was registered. After inhalation of atomized MNU solution, neither malformations nor toxic injuries could be observed. The experiments do not support the hypothesis, that anomalies found in the stillborn infant are caused by mother's contact with MNU. As demonstrated, in most cases it is very difficult to prove any interrelationship between a chemical agent and the occurrence of malformations in man. Therefore, similar observations should be published even if the connection cannot be ascertained exactly, for only by an accumulation of related cases a positive correlation can be verified.

Embryotoxic activity of indole derivatives

Embryotoxic activity of indole derivatives

Effects of Detergents on Mouse Fetuses

Two different types of liquid detergents for kitchin use, one of which contains linear alkylbenzene sulfonate (LAS) and another contains sodium alkyl ethoxy sulfate (AES) and polyoxyethylene alkyl ether (POEAE) as their main constituents, were examined for potential teratogenic and embryotoxic activity following percutaneous or subcutaneous administration.In the dermal application, both detergents were diluted with water as 0.5, 5, and 15% solutions. Each solution of the detergents was applied on the shaved dorsa of pregnant mice, once daily at dose of 0.5ml per mouse during pregnancy days 1-13 in LAS detergent and 0-13 in AES-POEAE detergent.In the subcutaneous administration, the detergent containing LAS was given once daily at doses of 30 and 150mg/kg during days 7-13 or 0-13 of pregnancy, and the detergent containing AES and POEAE was dosed once daily at doses of 5, 50, and 500mg/kg during days 7-13 of pregnancy.A slight reduction of pregnancy rate was observed only in the group treated dermally with 15% solution of the detergent containing LAS, but there were no significant differences between the values of the group and the control. No deleterious effects were noted on embryonic development in either treatment of both detergents. Some kinds of external anomalies were found in all groups with slightly higher incidences than the reported data on the incidence of spontaneous external anomalies in the ICR-JCL strain of mice, but the incidences of anomalous fetuses in the treated groups were not significantly different from those in controls. In all experiments, on fetuses with internal anomalies were found in all groups except only one case in the group treated with 150mg/kg LAS detergent. Some kinds of skeletal variations with low or considerably high frequency occured in all groups, but there were no statistical differences among the groups.In the subcutaneous studies, the numbers of fetuses with skeletal anomalies were not significantly increased in the treated groups as compared to the controls.The results of this study would suggest that there was no conclusive evidence of embryotoxic and teratogenic effects, assumed to be attributable to these detergents, in the mice.

Evaluation of the teratogenic activity of hycanthone in mice and rabbits.

Hycanthone has been tested for embryotoxic activity in mice and rabbits. Treatment of mice on days 6-11 of gestation produced little embryotoxicity at a dose of 12.5 mg/kg, but produced teratogenic effects at 25 mg/kg and induced almost complete intrauterine death at 50 mg/kg. Single injections on various days of gestation demonstrated that the mouse conceptus is most sensitive to hycanthone-induced teratogenesis on gestation days 6 and 7, at which time a high incidence of exencephaly and skeletal malformations was found. Hycanthone (50 mg/kg) given to pregnant mice on day 7 of gestation depressed DNA synthesis in embryonic tissue, an effect which was evident 30 minutes after drug treatment and which lasted at least 3 hours. Following a single injection of [3H-U]hycanthone into 7-day pregnant mice, radioactivity was rapidly cleared from the maternal plasma, having a half-life of 1-2 hours; higher levels of radioactivity were attained in the embryonic vesicles than in maternal plasma at all time intervals tested. Hycanthone also had embryotoxic activity in rabbits. A dose of 25 mg/kg increased the incidence of intrauterine death, and at 50 mg/kg both embryolethal and teratogenic effects were noted.

Assessment of the teratogenic potentials of surfactants: Part II — AOS

The surfactant α-olefin sulphonate (AOS) was examined for potential teratogenic and embryotoxic activity. The material was administered (by oral gavage) during days 6–15 of pregnancy in rats and mice, and days 6–18 of pregnancy in rabbits. Dosages employed were 0.2, 2, 300 and 600 mg/kg/ day. Maternal toxicity in the form of retarded weight gain or weight loss, death and/or total litter loss was apparent in rabbits and mice at 600 mg/kg, and to a lesser extent at 300 mg/kg; only slight affects were observed at 0.2 and 2 mg/kg. Rats showed no rection at the dosages tested. Litter parameters were unaffected at dosages that were either non-toxic or only slightly toxic to the dam, i.e. 0.2 and 2 mg/kg in rabbits and mice, 0.2, 2, 300 and 600 mg/kg in rats. Higher foetal loss (with consequent reduction in litter size) arising from an increased incidence of total litter losses occurred in mice at 300 and 600 mg/kg. Lower mean pup weight was observed in rabbits at 300 mg/kg and mice at 600 mg/kg. No rabbits survived at 500 mg/kg. The incidence of major malformations and of minor visceral and skeletal anomalies and skeletal variants (extra ribbed pups) appeared unaffected apart from higher incidences of minor skeletal anomalies and variants in rabbits at 300 mg/kg, and of major malformations (cleft palate)_and minor skeletal anomalies in mice at 600 mg/kg.

Assessment of the teratogenic potential of surfactants: Part I — LAS, AS and CLD

The surfactants linear alkylbenzene sulphonate (LAS), alcohol sulphate (AS) and the commercial light duty liquid detergent (CLD) containing 17% LAS and 7% sodium dodecyl ethoxy sulphate (AES), were examined for potential teratogenic and embryotoxic activity. The materials were administred (by oral gavage) during days 6–15 of pregnancy in rats and mice, and days 6–18 of pregnancy in rabbits. Dosages employed were 0.2, 2.0, 300 and 600 mg/kg/day for LAS and AS, and 0.8, 8.0, 1200 and 2400 mg/kg/day for CLD (except mice which received dosages of 1.064, 10.64, 1600 and 3200 mg/kg of CLD). Marked maternal toxicity in the form of anorexia, weight loss, cachexia, death and abortion (and/or total resorption) was evident in rabbits and mice with LAS at 300 and 600 mg/kg, and AS 600 mg/kg. CLD was markedly toxic to rabbits at 1200 or 2400 mg/kg and to mice at 3200 mg/kg. Slight to moderate maternal toxicity was observed with rats receiving LAS 600 mg/kg, AS 300 or 600 mg/kg, CLD 2400 mg/kg, with rabbits and mice receiving AS 300 mg/kg, and with mice receiving CLD 1600 mg/kg. Effects on litter parameters were generally restricted to dosages causing marked maternal toxicity, the principal effects being higher foetal loss (with consequent reduction in litter size) arising from the increased incidence of total litter losses. When dams showing total litter loss were excluded from the calculations, litter parameters were not unduly different from those of controls. At dosages that were either non-toxic or only slightly to moderately toxic to the dam, litter parameters were essentially unaffected. The incidences of major malformations and of minor visceral and skeletal anomalies were generally unaffected even at maternally toxic dosages, apart from a higher incidence of skeletal anomalies in mice at LAS 300 mg/kg and AS 600 mg/kg. Even the distribution of skeletal variants (extra ribbed pups) was not unduly affected, the only suggestions (by virtue of differences from concurrent and laboratory standard controls) of an association with treatment being the tendency for a higher incidence of extra ribbed rabbit pups with AS at 2.0 and 300 mg/kg, and a higher incidence of mice with cervical ribs with CLD at 3200 mg/kg.

Teratogenic activity of methadone hydrochloride in mouse and chick embryos

ABSTRACT Teratogenic activity of methadone HCl (Physeptone, Burroughs Wellcome and Co.) was tested on inbred JBT/Jd and outbred Q strain mouse embryos and on chick embryos. 22–24 mg/kg injected subcutaneously on the 9th day of pregnancy caused by the 13th day exencephaly in 56 out of 479 JBT/Jd embryos but after 32 mg/kg only in 1 out of 220 of the Q strain. Some affected JBT/Jd embryos showed also rachischisis in the cervical area. The second abnormality shown by the embryos of both strains is Z-shaped kinkage of the spinal cord. In explanted chick embryos cultured in vitro as well as in embryos treated in ovo metha-done causes non-closure of the neural tube with extensive necrosis of the neural plate cells in the cephalic region. The results of this study indicate that methadone, which is a neutropic drug, has an embryo-toxic activity directed against the developing central nervous system.

Effect of polymorphonuclear leukocytes on the development of mouse embryos cultured from the two-cell stage blastocysts.

The effect of polymorphonuclear leukocytes (PMNLs) on the development of pre-implantation mouse embryos cultured from the two-cell stage to blastocyst was investigated. PMNLs (1–2 × 106) blocked development of most embryos beyond the four- or eight-cell stage. The embryotoxic activity declined with decreasing PMNL concentration. The activity of intact PMNLs or equal numbers of PMNLs that were homogenized or lyophilized following homogenization was similar. However, acidification of PMNL homogenates prior to lyophilization appeared to increase their activity, while homogenization of PMNLs under hypotonic conditions appeared to decrease their activity. The embryotoxic activity was not destroyed by storage of whole PMNLs for 1 week at 4 C.

Embryotoxic activity of hypoglycin-A in the rat.

Embryotoxic activity of hypoglycin-A in the rat.

Thalidomide as a Possible Biological Acylating Agent

THE teratogenic activity of thalidomide is now well known, but the mechanism by which the drug produces foetal abnormalities is obscure. Recent investigations in this laboratory1 on the relationship between embryotoxic activity and chemical structure in a series of compounds related to thalidomide (α-phthalimidoglutarimide) suggested that the phthalimide portion of the molecule is important in determining teratogenic activity. Replacement of the phthalimide ring of thalidomide by other ring systems such as those of succinimide and hexahydrophthalimide was found to lead to the loss of embryotoxic activity in tho rabbit. However, replacement of the glutarimide ring of thalidomide by other groups did not in every case lead to complete loss of embryopathic activity, for 4-phthalimidobutyramide, phthalimidobenzene and 2-phthalimidoglutaric acid anhydride were still embryotoxic in rabbits but much less so than thalidomide. These observations suggested that an N-substituted phthalimide structure was essential for embryotoxic activity. However, the exact structural requirements in the N-substituent for embryotoxicity are not yet clear, but, so far as is known at present, optimum embryotoxic activity is found when the N-substituent is α-glutarimide as in thalidomide itself.

Embryotoxic activity of some pesticides and drugs related to phthalimide

The fungicides, phaltan ( N-(trichloromethylthio)phthalimide) and captan ( N-(trichloromethylthio)-Δ 4-tetrahydrophthalimide), the insecticide, imidan ( O,O-dimethyl S-phthalimidomethyl phosphorodithioate), and the diuretic, phthalamudine (3-(4′-chloro-3′-sulphamoyl)-3-hydroxyphthalimidine) were tested for embryotoxic activity by daily oral administration to pregnant New Zealand White rabbits on days 7–12 of pregnancy. These compounds had no significant embryotoxic effect.