Cleft Palate In Mice Research Articles

Corticosteroid-induced cleft palate in mice and H-2 haplotype: maternal and embryonic effects.

This report confirms and expands on the original preliminary observations made by Bonner and Slavkin that corticosteroid-induced cleft palate in mice is associated with H-2 haplotype. Using three congenic strains, B10, B10.A, and B10.D2, our studies demonstrate that B10.A (H-2a) is most susceptible and B10.D2(H-2d) is least susceptible, B10(H-2b) being intermediate. Variation in fetal loss among strains accounts for less than 1 percent of the variation in cleft-palate frequency among strains; variation in H-2 haplotype, however, accounts for more than 60 percent of the variation in cleft-palate frequency. With regard to all possible reciprocal F1 hybrids, our results indicate that while there is a significant maternal effect, maternal haplotype can account for only 11 percent of the variation in cleft-palate frequency among crosses. Embryonic haplotype accounts for 17 percent of the variation, which is indicative of an important embryonic effect. Finally, our studies suggest that susceptibility to corticosteroid-induced cleft palate is associated with the K end of the H-2 complex.

Experimental formation of cleft palate in mice with polychlorinated biphenyls (PCB)

The teratological effect of polychlorinated biphenyls (PCB) was examined using the ddY strain of mouse. PCB in 0.05 ml ethanol was injected daily, subcutaneously into the back of pregnant mice, for 10 days from day 6 of gestation. Cleft palates were found in fetuses at the 18th gestation, with a significant dose response between 10 mg and 50 mg as total body dose of PCB per pregnant mouse. Comparison of these results with simultaneous observations of body weight of dam or fetus, and number of resorbed and dead fetuses, indicated that cleft palate formation was due mainly to the specific effect of PCB and not to its general toxicity. Cleft lip, brachydactyly, and syndactyly were also found. In the control mice receiving no PCB and no treatment, no external malformations were found in 1765 live fetuses. These results demonstrate a teratogenic effect of PCB in the ddY strain of mouse after subcutaneous injection.

Stage of palate closure as one indication of "liability" to cleft palate.

A new inbred mouse strain, SW/Fr, developed from a random-bred SW stock has a 6% incidence of spontaneous cleft palate without cleft lip. SW/Fr mice close their palates comparatively late in development. After cortisone treatment, the mean of the distribution (mean time to reach palate stage 5) is shifted towards later gestational ages. There is no change in the variance of the distribution. These data lend further support to the hypothesis that cleft palate in mice may fit a model where a continuous distribution is separated into discontinuous parts by a developmental threshold, and that time of palate closure is an important component of liability to cleft palate.

Animal toxicology

Animal toxicology

Influence of Cobalt (Dietary), Cobalamins, and Inorganic Cobalt Salts on Phenytoin-and Cortisone-Induced Teratogenesis in Mice

Various cobalt-containing agents (cyanocobalamin, sodium cobaltinitrite, and cobaltous chloride), which formerly had been shown to prevent the onset of cleft palate in CF-1 mice injected with cortisone, were studied to determine whether they would afford similar protection against phenytoin. Phenytoin, however, failed to cause cleft palate in the mouse fetus when given to pregnant animals alone; and cortisone, on the contrary, induced this anomaly in the presence of the so-called cobalt antagonists as well as when administered in their absence. It is suggested from these results that high dietary intake of cobalt prevents cleft palate caused by phenytoin challenge and also negates the protective effects associated with the acute administration of cobalt compounds. Therefore, it is concluded that these well-known teratogens inhibit palatal closure in mice by different mechanisms.

Agent-determined type of maternal influence on induced cleft palate in mice.

The maternal influence on induced cleft palate frequency, as revealed by reciprocal crosses, was investigated after treatment with triamcinolone or cortisone. Mouse blastocysts from the CBA and A/Jax strains were transferred to pseudopregnant A/Jax and CBA foster mothers and in addition CBA X A/Jax and A/Jax X CBA embryos were raised in pseudopregnant CBA foster mothers. According to the period of maximum sensitivity revealed by a time response study triamcinolone was injected as a single dose (2 mg/kg, i.m.) on day 11 at 8 a.m. when the precocious development of transferred fetuses had been taken into account. A predominant uterine factor slightly modified by the fetal genome was found. This was in contrast to the effect of the 4-day treatment with cortisone (62.5 mg/kg i.m.) where, as also previously has been shown, cytoplasmic factors in the embryos were accountable for the magnitude of the teratogenic response. An increased corticoid elimination from the resistant CBA fetuses might explain the maternal influence on triamcinolone treatment but would not be responsible for the influence on cortisone-induced cleft palate frequency.

The ultrastructure of epithelium of palatal process of triamcinolone-induced cleft palate in mice

The ultrastructure of epithelium of palatal process of triamcinolone-induced cleft palate in mice

Some sources of nongenetic variability in steroid-induced cleft palate in mice.

C57BL/6JKt female mice mated to A/JKt males were each injected im with 50 mg/kg triamcinolone 13 days post-VP, and the roles of a number of nongenetic factors underlying variability in the frequency of cleft palate (CP) induced in the fetuses were analyzed. Litter size and number of young per uterine horn, overall, were not significantly related to the CP rate. But nearly one-quarter of litters (almost all larger-sized ones) contained CP rates deviating from-mostly less than-expected on a random basis. Analysis of litters with deviant CP distribution, as well as of all suitable litters, indicated that only maternal treatment-day weight was significantly associated, inversely, with CP frequency-in spite of the treatment dosage having been weight-based. There was no clear relation between the CP and resorption rates; but litters with deviant CP distribution had a significantly greater resorption rate than the others. Fetal weight was inversely related to CP rate even in litters of uniform size. Fetuses occupying uterine positions immediately caudal to those with CP had a significantly higher CP rate than those next to normals, and conceptuses caudal to resorptuses a significantly higher resorption rate than those next to surviving fetuses; but the reverse was not true: CP and resorption rates were not greater in those next to resorptuses and surviving fetuses, respectively.

Protective effect of tiopronin on methylmercuric chloride-induced cleft palate in mice

Protective effect of tiopronin on methylmercuric chloride-induced cleft palate in mice

Toxicity of polybrominated biphenyls (Firemaster BP-6) in rodents

Pregnant rodents were fed concentrations of a mixture of polybrominated biphenyls (Firemaster BP-6) during the pregnancy. The material appears to be weakly teratogenic, causing exencephaly and cleft palate in mice. Decreasing birth weight with increasing dosage of the material was seen in both mice and rats. Nonpregnant mice fed 1000 ppm Firemaster BP-6 for 11 days had a marked increase in liver size and weight.

Teratogenic acitivity of the antiepileptic drugs phenobarbital, phenytoin, and primidone in mice

The teratogenic activity of phenobarbital, phenytoin, and primidone was studied in mice derived from the ICI pathogen free strain. The drugs were administered in the diet or by gastric intubation either from days 6–16 or 12–16 of pregnancy (day of vaginal plug is day 1). This covered the period during which the mice are susceptible to agents inducing cleft palate. The mothers were killed 1 day before term and the fetuses were examined. Cleft palates were rarely seen in the controls, the incidence being only 3 out of 1103 (0.3%) fetuses. The incidence of cleft palate in mice treated with phenobarbital 50 or 150 mg/kg in the diet was 0.6 and 3.9%, with phenytoin 40 and 120 mg/kg by intubation, or 250 mg/kg in the diet was 0, 11.1 and 10.2%, and with primidone 100 to 250 mg/kg by intubation or 500–2500 mg/kg in the diet ranged up to 15%. Since changes in blood folate concentrations following the use of anticonvulsants might be related to the teratogenic effects observed, an attempt was made to antagonize the effects by the simultaneous administration of folinic acid. Folinic acid had no teratogenic action of its own, and had no effect on the incidence of cleft palate induced by phenobarbital in the diet, or by phenytoin by gastric intubation. However, it did significantly potentiate the teratogenic effects of phenytoin administered in the diet ( p < 0.002) but significantly reduced the teratogenic effect of primidone given in the diet ( p < 0.034).

Induction of cleft palate in mice after ophthalmic administration of hydrocortisone

Hydrocortisone is a glucocorticoid commonly used in ophthalmic preparations for its anti-inflammatory effects. Three levels of hydrocortisone sodium succinate, 0, 3, 15, and 30%, were ophthalmically applied to pregnant CD-1 mice on days 10–13 of gestation (day of mating is Day 0 of gestation). The drug concentrations were various multiples of the common therapeutic dosage level and were applied to both eyes in 1-μl drops five times a day. Eighteen-day fetuses were removed by cesarean section and examined for malformations. The incidence of cleft palate was significantly higher ( p < 0.05) in the medium- and high-dose treatment groups than in either the low-dose treatment group or saline-treated controls (52.8 and 73.2% vs 9.2 and 0%, respectively). There was no significant difference in the incidence of fetal deaths and resorptions between drug-treated and control fetuses.

Prenatal development of the vomer in normal and cleft palate mice.

AbstractIn mouse fetuses with cleft palate induced by cortisone, the shape of the entire nasal septal structure was slightly altered, due possibly to the lack of palatal shelf contact, but no significant changes occurred in the basic development of the vomer. Nor was any evidence found to show a direct or indirect influence of the vomer on structures involved in the formation of a cleft palate.

Induction of cleft palate in mice by tranquilizers and barbiturates.

AbstractSeveral barbiturates and tranquilizers, individually or in combination, were injected into pregnant mice of the A/J, CD1 and C3H strains in doses sufficient to induce sedation during the expected time of palate closure. Similar treatments were given during periods of fetal development 1 or more days prior to the time for normal palate closure. Among 2074 fetuses from treated pregnant females, 308 had isolated cleft palates. The most susceptible strains were A/J and CD1; the more teratogenic drugs were phenobarbital and hydroxyzine; the most critical treatment periods were at least 1 day prior to the time the palate would normally have closed. Thus, barbiturates and tranquilizers were shown to be significant cleft palate teratogens in mice although their mechanism of action was not investigated.

A simple method for non-surgical blastocyst transfer in mice.

In a recent book on methods in embryology, a whole chapter is devoted to eggtransfer technique (Dickmann, 1971). The reviewer states that is obvious that a non-surgical technique for transferring eggs into the uterus is preferable to a surgical one. The poor results from the non-surgical transfers of mouse eggs reported by Beatty (1951) and Tarkowski (1959) have apparently made many researchers reluctant to try this method, though Vickery, Erickson & Bennett (1969) described a fair success with non-surgical egg transfer in the rat. In our studies on the nature of the matroclinous influence on cortisoneinduced cleft palate in mice of the A/Jax strain, the vaginally transferred blasto¬ cyst technique was tried (Marsk, Theorell & Larsson, 1971). Since we have been fairly successful with the simple non-surgical blastocyst transfer, it seems appropriate to describe the method and give a summary of our results thus far.

Spatial relations in the oral cavity of cortisone-treated mouse fetuses during the time of secondary palate closure.

AbstractCortisone has long been used experimentally to induce cleft palate in mice, but the mechanisms by which it causes this effect remain controversial. It has been repeatedly demonstrated that after administration of cortisone the movement of the palatal shelves from a vertical to a horizontal position is delayed. The long‐accepted hypothesis is that during this delay growth of the head continues so that when the palatal shelves finally do become horizontal they are too far apart to meet in the midline and fuse. We found that maternally administered cortisone induced 95% cleft palate in ICR/DUB mouse fetuses observed at days 15–18 of gestation. Observations made on frozen, cryostat‐cut sections of fetal heads during the time of palate closure indicated that shelf elevation in experimental animals was delayed by as much as 12–14 h. However, when the shelves finally reached the horizontal they made contact with both the nasal septum and each other. It seems therefore that cortisone, beside causing delay in self movement, may also interfere with processes that occur subsequent to horizontalization leading to shelf fusion.

The modifying effect of folinic acid on diphenylhydantoin-induced teratogenicity in mice

To test the alleged association between diphenylhydantoin sodium (DPH) teratogenicity in animals and folic acid antagonism, inseminated female mice were treated ip with 50 mg/kg of DPH, a dose reported to be teratogenic in mice. They were given concurrent im doses of folinic acid (FA) of 1, 10, 20, 30, 40 and 100 mg/kg. The incidence of cleft palate in each group was determined. Statistical evaluation of the data demonstrated marked litter variance and a nonlinear modifying response. The incidence of cleft palate was not significantly different between groups receiving DPH alone and groups receiving DPH plus high doses (40–100 mg/kg) of FA or low doses (20 mg/kg) of FA. However, there was a significant difference ( p < 0.05) in the incidence of cleft palate between the groups receiving the high and low doses of FA. The data suggest that the various doses of FA, given concurrently with DPH, offer no significant protection against the development of cleft palate in mice, but do influence its incidence in a nonlinear fashion.

Sero-epidemiological studies of cleft palate and lip patients, and experimental formation of cleft palate in mice with rubella virus infection

Sero-epidemiological studies of cleft palate and lip patients, and experimental formation of cleft palate in mice with rubella virus infection

Isolated cleft palate in mice after transportation during gestation.

AbstractSubjecting pregnant mice to a 48‐hour transportation process during the 5 days of gestation prior to embryonic palate closure increased the frequency of isolated cleft palate (CP) in the fetuses examined just before delivery. The increase in CP rate was dependent on the mouse strain and the time of gestation during which transportation was carried out. Fourteen litters of A/J mice shipped on day 13 had 27% CP and 15% when shipment was made as early as day 10. In 14 litters of DBA/2J shipped day 13 there was 3% CP whereas ten litters of C57BL/6J and five litters of CBA/J shipped on day 13 had no CP. In ten litters of C3H/J shipped on day 12 there was one CP and none in ten litters shipped on days 13 or 14. The rank of relative CP susceptibility in the strains was the same as that produced by cortisone injection. This relation is interpreted in terms of interaction between variable maternal blood corticosterone levels in response to “stress” and variable fetal teratologic responsiveness.

Failure of muscle relaxants to produce cleft palate in mice

AbstractThis study was designed to examine the validity of the theory that descent of the tongue, which is presumably induced by fetal muscular movements, is essential for normal closure of the secondary palate in mice. Nulliparous CD1 mice were given the following “muscle‐paralyzing” agents on day 13° of gestation, i.e., 1 day before the onset of the critical period of palate closure: d‐tubocurarine chloride, gallamine triethiodide (Flaxedil), phenobarbital sodium, chlorphenesin carbamate (Maolate), and ethyl ether. The full paralytical effect of each drug was maintained for 42 hours, i.e., until day 15 1/3 of gestation, by means of subsequent fractional doses. Various combinations of barbiturates, anesthetics, and muscle relaxants were also employed. All litters were recovered by laparotomy on day 15° of gestation. The presence of fetuses that were flaccid, limp, apneic, and unresponsive to stimulation was accepted as evidence of transplacental passage of the employed compounds. No cleft palates were found in 656 recovered fetuses. This may be viewed as an indication that muscular activity — either spontaneous or reflexogenic — is not essential for normal closure of the secondary palate in mice.