Embryotoxic effects of sodium metavanadate administered to rats during organogenesis

Pregnant Sprague-Dawley rats were given orally a daily dose of 0, 5, 10 or 20 mg NaVO3/kg from the sixth through the fourteenth day of pregnancy. Fetal examinations were performed on day 20 of gestation. Sodium metavanadate was neither embryolethal nor teratogenic in rats when administered orally at 20 mg/kg/day or lower. Nevertheless, this dose was embryotoxic.     

Teratogenic action of platinum thymine blue

The teratogenic activity of the antitumor agent cisplatinum-2-thymine (platinum thymine blue) was investigated in rats. Pregnant Wistar-derived albino rats were given single ip injections of an aqueous solution of platinum thymine blue (PTB) at one day of pregnancy from day 5 through day 14 (sperm day=day 0). The dosages used ranged from 20 to 80 mg/kg maternal body weight. At autopsy (day 20) fetuses were recovered and subsequently examined for skeletal and soft-tissue abnormalities. PTB was embryolethal and teratogenic at several stages during rat gestation. Embryonic deat occured following all doses, and was dose dependent, except at day 5. The majority of malformed fetuses, however, were observed only after treatment at day 6 or 7 following injection with 50, 60, or 80 mg/kg. Eye defects were the predominant abnormality followed by hydrocephalus, gastroschisis, and ectopia cordis. The skeleton was only slightly affected. PTB is a potent inhibitor of DNA synthesis, but its mechanism of teratogenic action is unknown.     

A teratogenicity study on hydroxyurea and diphenylhydantoin in cats

Hydroxyurea, an antitumor drug and known teratogen in rat, miniature swine and dog, and diphenylhydantoin, a teratogen in mouse and rat, were assessed for teratogenic effects in cat. Pregnancies were induced, by synchronizing gonadotropin-stimulated estrus and ovulation with natural copulations. Hydroxyurea at 50 or 100 mg/kg, and sodium diphenylhydantoin at 1 or 2 mg/kg dosages, were administered orally in single daily doses from gestation days 10-22. Appropriate controls given empty capsules, were included for each drug. Cats were necropsied on gestation day 43. Fetuses were examined for external, visceral and skeletal malformations. Hydroxyurea at 50 mg/kg dose produced a low teratogenic activity and at 100 mg/kg a high incidence of non-pregnancy and resorptions with, consequently, fewer live fetuses. Diphenylhydantoin gave no clear evidence of teratogenicity at any test dose but was embryolethal at the maternally toxic dose of 2 mg/kg. So far, studies conducted suggest that the cat is a useful species for screening drugs and chemicals for their teratogenic potential.     

Teratogenic effects of the plant hormone indole-3-acetic acid in mice and rats.

These studies evaluated the teratogenic potential of indole-3-acetic acid (IAA), a naturally occurring plant hormone, in CF-1 mice and Sprague-Dawley rats. Mice were given 5, 50, 200, or 500 mg IAA/kg/day by gavage on days 7 through 15 of gestation. Rats were given 50, 200, or 500 mg IAA/kg/day by gavage on days 7 through 15 of gestation. IAA was teratogenic in mice and rats at 500 mg/kg/day; cleft palate was induced in both species at this dose level. In mice, other malformations including exencephaly, ablepharia, dilated cerebral ventricles, and crooked tail were also observed. Mice given 500 mg/kg of IAA gained less than control mice during gestation; no evidence of maternal toxicity was observed in rats. IAA did not cause fetal resorptions in either species and was not teratogenic at dose levels below 500 mg/kg.     

Cocaine as a cause of congenital malformations of vascular origin: experimental evidence in the rat

Cocaine hydrochloride was administered to pregnant Sprague-Dawley rats as a single intraperitoneal dose or as two doses 1-4 hours apart. A single dose administered on day 16 of gestation was teratogenic in a dose-dependent manner, with 40 mg/kg being a no-effect dose and 50 mg/kg the lowest teratogenic dose; 80 mg/kg was lethal to the dam. Forty-eight hours after exposure to a teratogenic dose on day 16 of pregnancy, the fetuses showed severe hemorrhage and edema in the their extremities, particularly the footplates, tail, genital tubercle, and upper lip/nose. When the fetuses were examined on day 21 of gestation, the main externally visible malformations were reduction deformities of the limbs and tail. When two doses of cocaine were administered 1-4 hours apart, the incidence of affected fetuses increased as the time interval between the two doses decreased. Two doses of cocaine administered 2 hours apart were not teratogenic on day 9, 10, 11, 12, 13, or 14 of gestation but did induce reduction deformities on days 15, 16, 17, 18, or 19. The same dose administered 1 hour apart was teratogenic on days 14-19. In general, cocaine administration on gestational days 14, 15, or 16 induced more severe and more widespread hemorrhage and edema than administration on days 17, 18, or 19. In the latter cases, damage was restricted to the distal parts of the hindlimb digits and the tail. The results show that in the rat cocaine is only teratogenic during the late organogenic or postorganogenic period.(ABSTRACT TRUNCATED AT 250 WORDS)     

Teratogenic and postnatal developmental studies of morphine in Sprague-Dawley rats

The teratogenic and postnatal developmental effects of morphine exposure during pregnancy were studied in Sprague-Dawley rats in three separate experiments using chronically implanted osmotic minipumps in order to avoid respiratory depression. In the first experiment, the teratogenic effects of three different morphine dosages were studied: a low dose (10 mg/kg/day), an intermediate dose (35 mg/kg/day), and a high dose (70 mg/kg/day). On day 5 of gestation, osmotic minipumps that deliver their contents at a constant rate for 15 days were implanted subcutaneously on the back of the rats. On day 20 of gestation, cesarean sections were performed, reproductive indices were determined, and fetuses were examined externally and then preserved for subsequent visceral and skeletal examinations. The pregnancy rate was significantly reduced at the intermediate and high doses to 57% and 6%, respectively (control, 83%). No teratogenic effects were observed at any dosage, but growth retardation was present in the intermediate-dose group. In the second experiment, postnatal survival of the offspring of dams treated with either normal saline, morphine (35 mg/kg/day), or the synthetic opioid, fentanyl (500 micrograms/kg/day) were studied. Offspring of morphine-treated dams had a significantly higher mortality rate, which peaked at 56% within 2 days. No effect was seen after fentanyl treatment. In the third experiment, pups of morphine-treated dams were cross-fostered by saline-treated dams; the postnatal mortality in offspring of morphine-treated dams remained high (62%). Our results indicate that doses of morphine up to 35 mg/kg/day delivered by osmotic minipumps are not teratogenic in rats but cause other adverse fetal effects that result in increased postnatal mortality.     

Teratogenicity of the antiallergic Sm 857 SE in rats versus rabbits

Sm 857 SE is an antiallergic drug chemically described as 11-Oxo-11H-pyrido(2,1-b)quinazoline-2-carboxylic acid that has activity against allergic bronchoconstriction in animal models. The purpose of this study was to investigate the teratogenic potential in pregnant rats and rabbits when administered during the critical period of organogenesis. The drug was suspended in aqueous 0.25% carboxymethylcellulose (CMC) solution. Daily doses of 20, 90, or 400 mg/kg were given orally by gavage to rats on days 7 through 17 of gestation and to rabbits on days 6 through 18. Two additional studies were done in rats dosed with 400 mg/kg, and with 90, 200, or 400 mg/kg, respectively. Doses of 20, 90, and 200 mg/kg had no meaningful effects on maternal animals of either species or on their offspring. A dose of 400 mg/kg was maternally toxic in rats as shown by the effects on body weight and food consumption. Among pregnant rabbits, two deaths and three miscarriages occurred at this dose. In rats, 400 mg/kg caused embryonic death, retarded fetal development, and two specific malformations, namely microphthalmia and vertebral-costal defects. A mild teratogenic action of 400 mg/kg also occurred in the first additional study but not in the second one. There was, however, one anophthalmia in a rat fetus of the 90 mg/kg group. In rabbits, no embryotoxic or teratogenic effects were observed. These species differences were explained by the concentration and protein binding in maternal serum as well as by the relatively high concentration of 14C-Sm 857 SE in the rat fetus.     

Cyclophosphamide teratogenesis: evidence for compensatory responses to induced cellular toxicity

Cyclophosphamide (CP) administered ip to pregnant mice on day 10 of gestation (day of plug = day 0) is teratogenic (exencephaly, cleft palate, and limb malformations) at 20 mg/kg and embryolethal at higher doses. In the present study, CP was administered at 1, 5, 10, or 20 mg/kg on day 10 of gestation. Embryos were removed at 8 and 28 hr postdosing, and two embryos from each litter were immediately stained with Nile blue sulfate (NBS) to identify areas of cell death. The remaining embryos were frozen and forelimb buds subsequently removed for flow cytometric (FCM) analysis of the cellular DNA synthetic cycle. Additional litters were examined near term (day 17) for morphological abnormalities; these data were correlated with embryonic toxicity as detected by NBS staining and FCM analysis. Only the highest dose produced malformations. In marked contrast, a dose-related increase in the percentage of limb bud cells in the S (DNA synthetic) phase of the cell cycle was detectable at all doses. Inhibition of DNA synthesis was detected at all doses 8 hr post exposure and persisted through 28 hr for doses greater than or equal to 10 mg/kg. NBS staining indicated increased cell death in the alar plate of the neural tube 28 hr after exposure to 10 mg/kg CP and generally increased cell death in areas of rapid cell proliferation throughout the embryo at 20 mg/kg. The absence of an overt teratogenic response at dose levels that produced significant perturbation of the cell cycle indicates that a measure of embryonic damage can be compensated for or repaired. The implications of these findings for the existence of thresholds in developmental toxicity are discussed.     

Salicylate-induced teratogenesis in the ferret

A single subcutaneous injection of 400 mg/kg sodium salicylate produced a high resorption rate on day 13 (91%) and on day 18 (66%) of gestation. Malformations were seen in the surviving fetuses. Pregnant ferrets injected with 250 mg/kg salicylate produced a lower resorption rate of between 31% and 43%. Malformations were seen in the surviving fetuses of animals injected with lower doses of sodium salicylate both at 13 and 18 days of gestation.Salicylate-induced teratogenicity at 400 mg/kg was compared with that produced in a closed colony of Wistar rats. The concentration of salicylate in whole blood (and serum) was determined after a single injection of 125 mg/kg or 400 mg/kg sodium salicylate. Although salicylate concentration in the blood in both species showed remarkable similarity at the doses tested and the times of sampling, the results indicated that the drug was far more embryo-toxic in ferrets than in rats. The inter-order variation in the embryotoxicity of sodium salicylate is such that it would be unwise to ignore its possible teratogenic activity in man.     

Teratogenicity and embryolethality of acrolein and structurally related compounds in rats

Acrolein, a metabolite of the anticancer agent cyclophosphamide, is teratogenic to rats after intraamniotic administration. It is not known whether acrolein or a metabolite of acrolein is responsible for the teratogenicity of this compound. We assessed the teratogenicity and embryolethality of acrolein and five structurally related compounds: acrylic acid, allyl alcohol, glycidol, glyceraldehyde, and propionaldehyde by intraamniotic injections in Sprague-Dawley rats on day 13 of gestation. All compounds tested were significantly embryolethal with at least one concentration of the drug. Acrolein was the most embryolethal of the drugs, causing a significant increase in resorptions with as little as 0.1 micrograms/fetus; the other drugs were embryolethal at doses 100-10,000 times that of acrolein. Acrolein was also the most teratogenic of the drugs tested; a dose as low as 5 micrograms/fetus caused a significant increase in the incidence of fetal malformations. Of the other compounds tested, only glycidol at a dose of 1,000 micrograms/fetus induced a significant number of malformed fetuses compared to control. These results suggest that it is acrolein itself that is responsible for its teratogenicity.     

Teratogenic effect of AY 9944 in rats: importance of the day of administration and maternal plasma cholesterol level

An inhibitor of cholesterol synthesis, AY 9944 (trans-1,4-bis(2-chlorobenzylaminomethyl) cyclohexane dihydrochloride) is teratogenic. A single dose of AY 9944 (50 mg/kg or 75 mg/kg) given to Wistar pregnant rats on the second, fourth, sixth, seventh, or eighth day of gestation induced malformations such as holoprosencephaly. They were often limited to isolated pituitary agenesis. The highest percentage of holoprosencephalic fetuses was found when AY 9944 was given on the fourth day of gestation. Whatever the dose and the day of administration, the lower the maternal plasma cholesterol level, the more frequent were holoprosencephalic fetuses. Therefore, it is suggested that the decrease in maternal plasma cholesterol level is at least one of the factors provoking holoprosencephaly.     

Influence of maternal stress on uranium-induced developmental toxicity in rats

It has been demonstrated that uranium is an embryo/fetal toxicant when given orally or subcutaneously to pregnant mice. On the other hand, maternal stress has been shown to enhance the developmental toxicity of a number of metals. In this study, maternal toxicity and developmental effects of a concurrent exposure to uranyl acetate dihydrate (UAD) and restraint stress were evaluated in rats. Four groups of pregnant animals were given subcutaneous injections of UAD at 0.415 and 0.830 mg/kg/day on Days 6 to 15 of gestation. Animals in two of these groups were also subjected to restraint for 2 hr/day during the same gestational days. Control groups included restrained and unrestrained pregnant rats not exposed to UAD. Cesarean sections were performed on gestation Day 20, and the fetuses were weighed and examined for malformations and variations. Maternal toxicity and embryotoxicity were noted at 0.830 mg/kg/day of UAD, while fetotoxicity was evidenced at 0.415 and 0.830 mg/kg/day of UAD by significant reductions in fetal body weight and increases in the total number of skeletally affected fetuses. No teratogenic effects were noted in any group. Maternal restraint enhanced uranium-induced embryo/fetal toxicity only at 0.830 mg/kg/day, a dose that was also significantly toxic to the dams. As in previous studies with other metals, maternal stress enhances uranium-induced developmental toxicity at uranium doses that are highly toxic to the dams; however, at doses that are less acutely toxic the role of maternal stress would not be significant.     

Teratology of intravaginally administered contraceptive jelly containing octoxynol-9 in rats

Octoxynol-9, a nonionic surfactant used as a spermicidal agent in ORTHO-GYNOL (registered trademark) Contraceptive Jelly (Ortho Pharmaceutical Corporation, Raritan, NJ), was administered intravaginally to pregnant Sprague Dawley COBS CD rats at dosages of 0.5 mg/kg/day and 5 mg/kg/day (two-thirds and six times the clinical dosage) on days 6-15 of gestation in order to assess its teratogenic potential. Untreated, sham, and vehicle control groups were also incorporated into the study protocol. No meaningful differences were observed between the treated and control groups in maternal toxicity, maternal reproductive parameters, fetal toxicity, and the incidence of external, visceral, and skeletal malformations or developmental variations. It is concluded that octoxynol-9 is not embryotoxic or teratogenic when administered intravaginally to rats during organogenesis.     

Corticosterone induction of cleft palate in mice dosed with orciprenaline sulfate

Orciprenaline sulfate is a beta-adrenoceptor stimulant chemically described as 1-(3,5-dihydroxyphenyl)-1-hydroxy-2-isopropylaminoethane sulfate (Alupent). The drug has broncho-dilating activity and has been developed in numerous countries since 1961. The purpose of these studies was to investigate the teratogenic potential of orciprenaline and its mode of action in pregnant Jcl:ICR mice, when administered during the period of organogenesis and, more systematically, during the critical period of palate formation. Daily doses of 5, 50, and 500 mg/kg were given orally by gavage to mice on days 6-15, 11-13, or on day 12 of gestation. Additional studies were done to evaluate the maternal cardiotoxic action of orciprenaline and its effects on adrenal cortex and endogenous serum corticosterone. Five mg/kg triamcin-olone acetonide, a glucocorticoid, were given subcutaneously as a positive control causing 100% cleft palate. Myocardial necroses occurred in pregnant mice only after 500 mg/kg orciprenaline had been given, and a significant increase in cleft palate occurred if exposure took place during days 11-13 or day 12 of gestation. This increase in cleft palate can be explained by the teratogenic effect of an elevated maternal serum corticosterone level 1 hr after orciprenaline treatment, about three times the control value.     

Teratogenesis of calcium valproate in rabbits

The calcium salt of valproic acid (Valontin) has been proposed for use in the treatment of absence, myoclonic, and tonic clonic seizures of the primarily generalized type. The present study was conducted to determine the teratogenic potential of calcium valproate in rabbits. Groups of 20 Dutch-belted rabbits were given oral doses of 50, 150, or 350 mg/kg on days 6-18 of gestation. A reference group was given 350 mg/kg sodium valproate and control groups were untreated or given vehicle alone. Animals were observed daily and body weights were recorded on gestation days 0, 6, 13, 18, and 30. Litter and fetal parameters were evaluated following uterotomies on day 30. No drug-related clinical signs or deaths occurred. Postimplantation loss and the incidence of malformed vertebrae and ribs, rudimentary or absent pollices, and extra vertebrae and ribs were increased at 350 mg/kg with both calcium and sodium salts of valproic acid. At the 150-mg/kg dose level, calcium valproate markedly increased the incidence of supernumerary ribs. No teratogenic or embryotoxic effects were seen with calcium valproate at 50 mg/kg. These data indicate that the sodium and calcium salts of valproic acid exhibit teratogenic potential in rabbits.     

Abortifacient principle of Achyranthes aspera Linn

Achyranthes apsera is an abundant indigenous herb in India. Extracts of the whole plant had shown an abortifacient effect in mice. Maximal activity was in the benzene extract which was tested. The drug, in olive oil, was given orally to rabbits in doses of 50 mg/kg of body weight on the 8th day postcoitum. Laparotomy was done on the 11th day. No implantation sites were found. However, ovaries contained prominent corpus luteum, indicating that the drug had prevented pregnancy. In rats, the drug was given orally as a single dose of 50 mg/kg of body weight on the 6th or 7th day after mating. No effect was observed. In mice the drug was given at a single dose of either 10, 15, 25, or 50 mg/kg of body weight. For toxicity tests in mice, a single dose of 1000 mg/kg of body weight was given. After 1 month animals were autopsied and the organs examined. The drug was nontoxic. For a chronic toxicity test 75 mg/kg of body weight was given every 21 days. After 6 months of drug treatment, blood and tissue samples were examined. No toxic effects were observed. For a teratogenic study, 15 mated female mice were fed 10 or 25 mg/kg of body weight on Day 6 of gestation. 3 generations of offspring showed no malformations. In mice, abortifacient effects were noted with a maximum activity at 50 mg/kg of body weight. The drug showed no estrogenic, antiestrogenic, or androgenic effects in mice. Progesterone or pituitary extract given along with the drug did not prevent abortions in mice. The drug was species-specific in that no abortifacient effect was found in rats.     

The teratogenic activity of a thalidomide analogus EM12 in rats on a low-zinc diet.

The relationship between the teratogenicity of EM12, 2-(2,6-dioxopiperiden-3'-yl) phthalimidine, a stable analogue of thalidomide, and zinc status in the maternal animal was investigated using pregnant rats on a low-zinc diet (1 ppm zinc, days 0--14 gestation) as the experimental model. Previous studies with this compound in rats fed a commercial diet at oral doses up to 250 mg/kg per day for three days and intravenous doses up to 10 mg/kg per day for three days failed to produce "typical" thalidomide malformations. However, when a dose of 150 mg/kg was given intraperitoneally to rats on a low-zinc diet, typical thalidomide malformations occurred with an incidence of 57.5%.     

Perinatal death and respiratory apparatus dysgenesis due to a bis (dichloroacetyl) diamine

N, N1-bis (dichloroacetyl) diamine 1, 8-octomethylenediamine (WIN 18,446) is an experimental drug which was first investigated as a male contraceptive. It is soluble in lipid solvents but not in water. The administration of 1,200 to 1,600 mg/kg to pregnant rats on the tenth day of gestation produced multiorgan fetal malformations. Smaller doses, 400 to 800 mg/kg, especially if divided over 2 or 3 days, caused perinatal death. Thus, 60 to 100% of offspring of rats given WIN 18,446 on the tenth and 11th days of gestation died at birth or within 4 days (Taleporos et al., 78). The present study investigated such deaths. At doses of 200 mg/kg on day 10 or 50 mg/kg on days 10 and 11, 67% of offspring had defective or absent diaphragms, 48% had tracheobronchiomegaly with cystic lungs, and 67% had pleural hemorrhage. At doses of 100 mg/kg given on 1 day or 25 mg/kg each day for 2 days, 50% had tracheobronchiomegaly with cystic lungs and rudimentary acini. At lower doses (18.8 mg/kg X 2 or 12.4 mg/kg X 3), a majority of fetal lungs had rudimentary acini, thick septa, few capillaries, and wide cuffs of perivascular connective tissue. Thus, a chemical given during organogenesis produced dysgenesis of the respiratory apparatus. Varying the dose produced malformed lungs with persistently deficient acini which model such human lung faults as tracheobronchiomegaly (Mournier-Kuhn Syndrome; Mounier-Kuhn, '32), bronchiolar dysplasia (Wilson-Mikity Syndrome), and perinatal death with acinar failure resembling neonatal hyaline membrane disease.     

Variability in the developmental toxicity of bropirimine with the day of administration

The aim of this study was to determine the mechanism by which bropirimine exerts its developmental toxicity. This drug is an immunomodulator and interferon inducer with antiviral and antitumor activities in experimental models. Timed-pregnant Upj:TUC(SD)spf (Sprague-Dawley) rats were given a single oral (gastric intubation) dose of bropirimine at 200 or 400 mg/kg (doses as high as 100 mg/kg/day have been employed in human cancer trials) on days 5, 6, 7, 8, 9, 10, 11, or 12 of gestation and in a second experiment on day 12, 13, 14, 15, 16, 17, 18, or 19 of gestation. The dams were killed 24 hours after dosing and their uterine contents examined. In a third experiment, bropirimine (400 mg/kg) was administered on day 4 of gestation and the uteri of different groups were examined on day 8, 9, 10, 11, or 12 of gestation. Serum progesterone levels were measured at sacrifice. In the first two experiments a battery of hematologic/clinical chemistry assays also were performed. In all three experiments, bropirimine-related maternal toxicity was observed; such toxicity was characterized by significant decreases in weight gain, relative to the concurrent vehicle controls, as well as significant differences in several blood parameters including platelets, white blood cells, alanine aminotransferase, and aspartate transaminase. In the first experiment, bropirimine treatment on day 11, but not day 12, resulted in significant decreases in the mean number of live embryos per litter. In the second experiment, significant decreases in the number of live fetuses per litter occurred 24 hours after dosing on day 18 (200 and 400 mg/kg groups) or day 19 (400 mg/kg group). Decreases in serum progesterone appeared to correlate well with the embryolethal effects seen after treatment between days 6 and 11 of gestation, but not with the fetal lethality seen when treatment was given on day 17 or 18. The decreases in serum progesterone levels found most likely were the result of a luteolytic effect, although it is unknown if bropirimine has a direct or indirect effect on the corpora lutea. In the third experiment, bropirimine treatment on day 4 of gestation resulted in only slight preimplantational losses, but significant decreases were found in mean number of live embryos per litter after day 9. Uterine decidual necrosis has been observed in the first experiment where bropirimine was given on day 11; however, treatment on day 4 resulted in an apparent decrease in decidual development but not necrosis.     

Teratogenic effects of chlorambucil on in vivo and in vitro organogenesis in mice.

Pregnant ICR/DUB mice were each given a single oral injection of chlorambucil (14.2 or 20 mg/kg) on the 10th, 11th, 12th, or 13th day of gestation (plug day = 1st day). Fetuses examined on the 18th day were decreased in weight and had tail, cranial, and limb defects. They type and frequency of malformations differed according to the dosage and day of treatment. Limb defects resulted from treatment on the 11th or 12th days of gestation and tail defects from treatment on all days. Control limb buds from 12th day embryos cultured for 6 days in serum-supplemented BGJ medium containing 0.5-2 mug/ml chlorambucil were retarded in development and had cartilage abnormalities. The extent of the deformities was dose related. Limb buds were also taken from embryos 24 h after in vivo exposure to teratogenic doses of chlorambucil and cultured in control medium. After 6 days in culture these limbs also had growth impairment and cartilage abnormalities. The defects in limbs exposed in vitro were similar to those in limbs exposed in vivo.