Influences of prenatal and postnatal fraternity size on ovarian development in the mouse

An experiment was conducted to test effects of prenatal and postnatal fraternity size (size of litter in which an individual develops prenatally or is reared postnatally) on ovarian development in mice. Fraternity size treatments were created by standardizing sizes of prenatal and postnatal fraternities in which mice were gestated and reared. Prenatal fraternity size was standardized by surgery on Day 9 of gestation to 6, 10, and 14 fetuses. Postnatal fraternity size was standardized by randomly assigning pups to litters of 5, 10, or 15 pups within 24 h of birth. Female pups were killed at either 3 or 20 wk of age and right ovaries were prepared for histology. Follicles were classified by size and morphology, and numbers of follicles in each class were tabulated. Interaction of postnatal fraternity size and age was observed for number of antral follicles (p less than 0.05). Mice reared in small postnatal fraternities had more antral follicles at weaning (3 wk) and fewer antral follicles at maturity (20 wk of age) than mice reared in large postnatal fraternities. No effect of either prenatal or postnatal fraternity size on other follicle populations was observed (p greater than 0.20). Numbers of Type 2 (primordial), Type 3a, and Type 3b follicles changed with age (p less than 0.01); numbers of primordial follicles declined with age, but numbers of Type 3a and 3b follicles increased. A hypothesis of a negative association between postnatal fraternity size and number of antral follicles at 3 wk of age was supported, but a hypothesis of a positive association between fraternity size and number of primordial follicles was not supported.     

The relative importance of prenatal and postnatal maternal influences on growth in mice

Summary The cross-nursing technique was used to assess the relative importance of prenatal and postnatal maternal influences on growth in mice from an unselected population originated from a cross of four highly inbred strains. Body weights were studied at birth, 7-, 14-, 21- and 42-days, in addition to the weight gains between these ages and tail length at 21 and 42 days of age. At littering, each dam in each nursing set retained two of her own offspring and two were transfereed to each of the other dams in the set, so that each nursed litter contained six young representing three mothers. Prenatal influences accounted for 37, 15, 10, 11 and 13 % of the total variation in the respective body weights, while postnatal influences accounted for 0, 64, 65, 49 and 14% at the respective ages. In the case of weight gains, prenatal influences were responsible for 16, 4, 6 and 30%, while postnatal influences were responsible for 66, 66, 31 and 7% of the total variation in gain during the respective four periods examined. Apparently the individual weight gain from 7 to 14 days was a better measure of the lactational performance of the dam than individual 14-day weight. For tail length, prenatal influences accounted for 6 % and 4 % of the total variation in tail length at 21 and 42 days, respectively, while postnatal influences accounted for 60 % and 24 % at the respective ages. Generally, there was no indication of an important interaction between the nurse and the nursed young at any stage studied.     

Disentangling prenatal and postnatal maternal genetic effects reveals persistent prenatal effects on offspring growth in mice

Mothers are often the most important determinant of traits expressed by their offspring. These "maternal effects" (MEs) are especially crucial in early development, but can also persist into adulthood. They have been shown to play a role in a diversity of evolutionary and ecological processes, especially when genetically based. Although the importance of MEs is becoming widely appreciated, we know little about their underlying genetic basis. We address the dearth of genetic data by providing a simple approach, using combined genotype information from parents and offspring, to identify "maternal genetic effects" (MGEs) contributing to natural variation in complex traits. Combined with experimental cross-fostering, our approach also allows for the separation of pre- and postnatal MGEs, providing rare insights into prenatal effects. Applying this approach to an experimental mouse population, we identified 13 ME loci affecting body weight, most of which (12/13) exhibited prenatal effects, and nearly half (6/13) exhibiting postnatal effects. MGEs contributed more to variation in body weight than the direct effects of the offsprings' own genotypes until mice reached adulthood, but continued to represent a major component of variation through adulthood. Prenatal effects always contributed more variation than postnatal effects, especially for those effects that persisted into adulthood. These results suggest that MGEs may be an important component of genetic architecture that is generally overlooked in studies focused on direct mapping from genotype to phenotype. Our approach can be used in both experimental and natural populations, providing a widely practicable means of expanding our understanding of MGEs.     

Effect of exposure to high isoflavone-containing diets on prenatal and postnatal offspring mice

Isoflavone (IF), a type of phytoestrogen, has multiple beneficial effects, but too much phytoestrogen can have adverse effects on offspring. To examine whether chronic exposure to high IF has adverse effects on reproductive development, mice offspring were exposed to IF through dietary administration to dams during pregnancy and lactation and to the offspring directly after weaning until sacrifice. In male offspring, there was no difference between the IF group and controls; however, in female offspring in the IF group, remarkably earlier puberty and induction of multioocyte follicles on postnatal day (PND) 21 were observed. Gene expression levels of estrogen receptor beta decreased in the ovary and vagina on PND 21. These results suggest that chronic exposure to higher than normal levels of IF induces alterations in the reproductive development of female mice through an estrogenic effect.     

Maternal zinc deficiency impairs brain nestin expression in prenatal and postnatal mice

INTRODUCTIONZinc is essential for normal brain development,evidenced by the fact that zinc deficiency in lactating mothers is characterized by a high incidence ofneuroanatomical maiformatinns and functional abnormalities in suckling offspring[1-3]. By colltrast,relatively little is known about the relationship be{tween maternal zinc nutrition and fetal brain development[2, 4, 5]. Dvergsten et al[6-81 investigated theeffects of maternal zinc deficiency on postnatal development of the rat ce…     

Effect of selection for spot size on reproduction and body weight in mice

Summary Spot size in descendants from the Goodale white-spotted stock of mice responded to selection for increased spot size. The realized heritability estimate was 0.52. However, no correlated response of reproduction to spot size selection was found in the present study, nor was there any correlated response among body weight variables.Joint project of Purdue University and USDA-SEA-ARS, North Central Region. Journal paper number 8279 from the Purdue Agricultural Experiment Station     

The effects of aluminium ingestion on reproduction and postnatal survival in rats

Aluminium nitrate was tested for its effects on reproduction, gestation, and lactation in Sprague-Dawley rats, at dosages of 0, 180, 360 and 720 mg/kg/day. Mature male rats were treated orally for 60 days prior to mating with mature virgin female rats treated for 14 days prior to mating with treatment continuing throughout mating, gestation, parturition, and weaning of the litters. One-half of the dams in each group were killed on day 13 of gestation and the remaining dams were allowed to deliver and wean their offspring. Postnatal development was monitored. No adverse effects on fertility or general reproductive parameters were evident at doses employed in these studies. However, the survival ratios were higher for the control group. Moreover, a dose-dependent delay in the growth of the living young could be observed in aluminium treated groups. Therefore, it would seem that high amounts of aluminium should not be ingested during the periods of gestation.     

Family networks in prenatal and postnatal health

This paper examines the effects of kin access on prenatal health practices, birth outcome, and postnatal health practice for infants born to black and white mothers ages 21 to 28 in the U.S. during 1984-86. The data used for this research were compiled from three sources: (1) The National Longitudinal Survey of Youth; (2) The Children of the National Longitudinal Survey of Youth; (3) special kin access data files, which were created specifically for this study. Logistic regression procedures are used to assess the effects of kin proximity, maternal grandmother proximity, and presence of the child's father on health practices (N = 1,030) and birth outcome (N = 1,385), controlling for the mother's educational attainment, work experience, poverty, presence of the child's father, and birth order of the child. We find no evidence supporting the notion that kin access positively affects the prenatal and postnatal health practices of young mothers. The results suggest that young mothers who reside with their mothers or other adult kin, and those who are in close proximity to them, are no more likely to seek prenatal care during the first trimester, or to avoid smoking or drinking during pregnancy. Mothers who live with a sexual partner or husband are, however, somewhat more likely to seek prenatal care and to avoid alcohol use during pregnancy. Closer kin access is associated with a lower probability of breastfeeding. These results suggest that it will not be adequate to rely on kin networks or kin assistance to improve the prospect of healthy birth outcomes.     

Family networks in prenatal and postnatal health

Abstract

This paper examines the effects of kin access on prenatal health practices, birth outcome, and postnatal health practice for infants born to black and white mothers ages 21 to 28 in the U.S. during 1984–86. The data used for this research were compiled from three sources: (1) The National Longitudinal Survey of Youth; (2) The Children of the National Longitudinal Survey of Youth; (3) special kin access data files, which were created specifically for this study. Logistic regression procedures are used to assess the effects of kin proximity, maternal grandmother proximity, and presence of the child's father on health practices (N = 1,030) and birth outcome (N = 1,385), controlling for the mother's educational attainment, work experience, poverty, presence of the child's father, and birth order of the child. We find no evidence supporting the notion that kin access positively affects the prenatal and postnatal health practices of young mothers. The results suggest that young mothers who reside with their mothers or other adult kin, and those who are in close proximity to them, are no more likely to seek prenatal care during the first trimester, or to avoid smoking or drinking during pregnancy. Mothers who live with a sexual partner or husband are, however, somewhat more likely to seek prenatal care and to avoid alcohol use during pregnancy. Closer kin access is associated with a lower probability of breastfeeding. These results suggest that it will not be adequate to rely on kin networks or kin assistance to improve the prospect of healthy birth outcomes.     

The influence of dietary copper on reproduction, growth and the cardiovascular system in Swiss-Webster female mice

One hundred forty pubertal Swiss-Webster female mice (Mus musculus) were assigned randomly to a purified diet modified to contain 1, 2, 3, 4, 5 and 6 ppm copper as copper carbonate (Diets 1 thru 6, respectively). Diet 7 was a commercial rodent laboratory diet containing 11 ppm copper. Following 60 days of prefeeding, the breeding regimen was initiated by introducing a proven breeder male into each cage of 10 females in the afternoon and removing them the next morning. The breeding regimen was conducted for 28 days and females were either sacrificed at 24 or 96 hours following detection of a vaginal plug. Body weight, hematocrit, heart weight, hemoglobin concentration, ova recovery rate and fertilization rate were recorded for each female. All morphologically normal embryos collected 24 hours after detection of the vaginal plug were cultured and development in vitro evaluated. Body weight, hemoglobin concentration and hematocrit were lower (P less than .05), and heart weight and percent body weight occupied by the heart (%BWOH) were higher (P less than .05) in mice fed Diet 1. Heart weight and %BWOH were not different among mice fed Diets 2 thru 6 (P greater than .05). Ova recovery rate and fertilization rate were significantly reduced in mice maintained on Diet 1. The incidence of in vitro blastocyst formation was lower in embryos collected from females fed Diets 1 and 3 (P less than .05). Blastocyst hatching in vitro was not observed in embryos from females maintained on Diet 1, and was greater in embryos from females fed Diets 4, 5, and 7 (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)     

New insights on the influence of free d-aspartate metabolism in the mammalian brain during prenatal and postnatal life

Free d-aspartate is abundant in the mammalian embryonic brain. However, following the postnatal onset of the catabolic d-aspartate oxidase (DDO) activity, cerebral d-aspartate levels drastically decrease, remaining constantly low throughout life. d-Aspartate stimulates both glutamatergic NMDA receptors (NMDARs) and metabotropic Glu5 receptors. In rodents, short-term d-aspartate exposure increases spine density and synaptic plasticity, and improves cognition. Conversely, persistently high d-Asp levels produce NMDAR-dependent neurotoxic effects, leading to precocious neuroinflammation and cell death. These pieces of evidence highlight the dichotomous impact of d-aspartate signaling on NMDAR-dependent processes and, in turn, unveil a neuroprotective role for DDO in preventing the detrimental effects of excessive d-aspartate stimulation during aging. Here, we will focus on the in vivo influence of altered d-aspartate metabolism on the modulation of glutamatergic functions and its involvement in translational studies. Finally, preliminary data on the role of embryonic d-aspartate in the mouse brain will also be reviewed.     

Genetic prenatal maternal effects on organ size in mice and their potential contribution to evolution

Two embryo transfer experiments were carried out in order to estimate the magnitude of prenatal maternal effects, independent of postnatal maternal factors, on the growth of internal organs and fat pads in mice. Reciprocal embryo transfers between the inbred mouse strains C3HeB/FeJ and SWR/J yielded three significant findings. First, all traits were not equally influenced by prenatal maternal factors. Genetic prenatal maternal factors, stemming from the genotype of the uterine mother, had a significant effect on testis weight, subcutaneous fat pad weight and epididymal fat pad weight in 21 day old progeny, but they had no effect on cranial capacity, an index of brain size, kidney weight, or liver weight. Prenatal litter size, defined as the sum of live and dead pups at birth, had a significant negative relationship with 21 day testis weight and kidney weight, and a significant positive association with subcutaneous and epididymal fat pad weights. Cranial capacity and liver weight at 21 days postnatally were not influenced by prenatal litter size. Second, the experiments demonstrated that there was ontogenetic variability in the strength of prenatal maternal effects. At 70 days of age, only subcutaneous fat pad weight was significantly influenced by genetic prenatal effects, and prenatal litter size had a significant negative relationship only with subcutaneous fat pad weight and body weight. Third, genetic prenatal effects had a significant influence on the among-trait covariances at 21 days postnatally, but not at 70 days. Because multivariate evolution involves covariances among characters, the latter results suggest that prenatal effects due to the mother's genotype can affect phenotypic evolution of mammals, especially for selection imposed early in life.     

Coadaptation of prenatal and postnatal maternal effects

In a wide variety of species, a female's age of first reproduction influences offspring size and survival, suggesting that there exists an optimal timing of reproduction. Mothers in many species also influence offspring size and survival after birth through variation in parental care. We experimentally separated these effects in the burying beetle Nicrophorus vespilloides to test for coadaptation between prenatal and postnatal maternal effects associated with age at first reproduction. Females that reproduced early produced offspring with lower birth weight. The amount of parental care depended on the age of first reproduction of the caretaker, as did the extent of offspring begging. As predicted for a coadaptation of maternal effects, prenatal and postnatal effects were opposite for different-aged mothers, and larval weight gain and survival was greatest when the age of the caretaker and birth mother matched. Thus, prenatal effects intrinsically associated with age of first reproduction can be ameliorated by innate plasticity in postnatal care. A coadaptation of prenatal and postnatal maternal effects may evolve to allow variable timing of the first reproductive attempt. Such a coadaptation might be particularly valuable when females are constrained from reproducing at an optimal age, as, for example, in species that breed on scarce and unpredictable resources.     

The effect of low-level prenatal X-irradiation on postnatal development in the Wistar rat

The objective of this investigation was to determine the effect of low-dose prenatal X-irradiation on postnatal growth and neurobehavioral development, and whether alterations would manifest at dosages lower than those which produce anatomic malformations from exposure at the most sensitive period of organogenesis. Ninety-eight Wistar strain rats were exposed to 0.1, 0.2, or 0.4 Gy X-radiation of were sham irradiated on the 9th or 17th day of gestation. A conventional teratologic evaluation was completed on half of the animals (572 fetuses). The age of appearance of four physiologic markers and of acquisition of six reflexes was observed in 372 offspring. Exposure during early organogenesis at these levels had no effect on any of these parameters. Prenatal exposure to X-radiation on the 17th day of gestation at dosage levels greater than 0.1 Gy resulted in alterations in the appearance of three postnatal neurophysiologic parameters. Growth retardation throughout the postpartum period also was observed in the offspring. The induction of developmental and reflex alterations had a comparable threshold to the known threshold for anatomic malformations on the 9th day. These results indicate that all of the parameters studied had thresholds either at or above 0.2 Gy acute radiation, and that the postpartum developmental and reflex acquisition measures were not more sensitive indicators of exposure to X-radiation than growth parameters.     

The influence of pheromones produced by freely growing laboratory populations on the reproductive maturation of prairie deermice following prenatal and postnatal exposure

Significantly more females reared on bedding soiled by different populations reproduced by 100 days of age than those reared on bedding soiled by the same populations (P<.1) or on clean bedding (P<.025) whereas the latter two groups did not differ significantly. Significantly greater percentages of females reproduced in both treatments maintained on soiled bedding than was true in the populations from which the bedding came. There were no significant differences between treatments in the weights of the reproductive organs (testes, seminal vesicles, ovaries, uteri) or in the numbers of corpora lutea or mature follicles in the ovaries of nulliparous females. The data suggest that if there were reproductively inhibiting pheromones influencing the population animals, they were altered or dissipated immediately after removal of the bedding from the population enclosures or that they were nonfunctional in the absence of the population animals. These data further suggest that the reproductive inhibition of population young is due to the presence of the populaton animals and that sociobiological factors within the populations act to prevent the reproductively stimulating influence of materials which may be present.     

The influence of pheromones produced by freely growing laboratory populations on the reproductive maturation of prairie deermice following prenatal and postnatal exposure

Summary Significantly more females reared on bedding soiled by different populations reproduced by 100 days of age than those reared on bedding soiled by the same populations (P<.1) or on clean bedding (P<.025) whereas the latter two groups did not differ significantly. Significantly greater percentages of females reproduced in both treatments maintained on soiled bedding than was true in the populations from which the bedding came. There were no significant differences between treatments in the weights of the reproductive organs (testes, seminal vesicles, ovaries, uteri) or in the numbers of corpora lutea or mature follicles in the ovaries of nulliparous females. The data suggest that if there were reproductively inhibiting pheromones influencing the population animals, they were altered or dissipated immediately after removal of the bedding from the population enclosures or that they were nonfunctional in the absence of the population animals. These data further suggest that the reproductive inhibition of population young is due to the presence of the populaton animals and that sociobiological factors within the populations act to prevent the reproductively stimulating influence of materials which may be present.     

Effects of pulsing electromagnetic fields on the prenatal and postnatal development in mice and rats: in vivo and in vitro studies

Electromagnetic fields (EMF) might have various biological effects on the developing embryo. We studied the effects of pulsing electromagnetic fields (PEMF) on the in vitro development of preimplantation mouse embryos and of early somite rat embryos as well as on the in vivo development of rat embryos. We used PEMF at frequencies of 1, 20, 50, 70, and 100 Hz with a tension of 0.6 V/m. The embryos were exposed to PEMF throughout the experimental period. PEMF at frequencies of 20 and 50 Hz were embryotoxic, inhibiting over 50% of blastocysts from hatching and further development, all within 72 h of culture. PEMF at frequencies of 50 and 70 Hz induced 22% and 30% incidence of malformations in 10.5 day old rat embryos after 48 h in culture. The main malformations were absence of telencephalic, optic, and otic vesicles and of forelimb buds. In addition, retarded growth and development manifested by fewer somites, reduction in crown-rump length, and retarded closure of the neural tube were found in many embryos. No significant pathological changes were found by TEM in PEMF-exposed embryos. Disappearance of microvilli and collapse of apical parts of endodermal cells were observed by SEM in many yolk sacs of embryos exposed to 50 and 70 Hz PEMF. A slightly reduced litter average, a reduction or increase of weight, and a delay in eye opening was observed among offspring of pregnant rats exposed throughout pregnancy to PEMF at frequencies of 20, 50, and 100 Hz. No malformations were observed among these offspring. The mechanism of PEMF-induced embryotoxicity and teratogeneity is unknown, as is the mechanism of the "protective effects" of the mother on the rat embryos exposed to PEMF in vivo.