Decreased Litter Size Research Articles

Slc2a8 Deficiency in Mice Results in Reproductive and Growth Impairments1

SLC2A8, also known as GLUT8, is a facilitative glucose transporter expressed in the testis, brain, liver, heart, uterus, ovary, and fat. In this study we examined the effect of Slc2a8 deficiency on mouse gamete, preimplantation embryo, and implantation phenotype, as well as postnatal growth and physiology. For this model, the transcriptional start site and exons 1-4 were targeted and a lack of protein expression was confirmed by Western immunoblot. Oocytes obtained from Slc2a8(-/-) mice demonstrated abnormal metabolism and ATP production. In addition, deletion of Slc2a8 resulted in impaired decidualization, a critical step in the differentiation of endometrial stromal cells (ESCs), necessary for implantation. This indicates a role for SLC2A8 in decidualization, which is supported by Slc2a8 mRNA expression in both mouse and human ESCs, which increases dramatically in response to hormonal changes occurring during the process of implantation. Ovarian transplantation studies confirm that lack of SLC2A8 affects both the embryo and the implantation processes. This phenotype leads to decreased litter size, and smaller pups at weaning that continue to display an abnormally small growth phenotype into adulthood. The Slc2a8 null mice display decreased body fat by magnetic resonance imaging, and, interestingly, they are resistant to a diet high in fat and carbohydrates.

Effects of Achillea Millifolium extract consumption by pregnant mice on pregnancy outcome and reproductive system of their female off spring

Background: Achillea millefolium (Yarrow) is medicinal plant that is traditionally used against inflammatory and spasmodic gastrointestinal compliant.Objective: To study the effect of the consumption of Achillea extract by pregnant mice on pregnancy out come and on the reproductive system of the female off spring.Materials & Methods: 70 adult pregnant female mice at age of 40-45 days were used in this study. These 70 mice were divided equally into two groups: experimental group (G1) and control group (G2). The experimental group was given 1mg/kg body weight/1ml of D.W of Achillea millefolium extract orally during 3 weeks of pregnancy, while the control group was given 1ml of D.W orally alone and for the same period. After delivery the number and weight of the litters were recorded. 40 days after delivery, the weight of the female reproductive system was estimated, histological sections were done for the ovaries and oviducts, their diameters were measured, in addition serum was taken from these mice and measurement of FSH, LH and E2 was done for both groups. Results: The results of the experimental group showed highly significant decrease in litter size and significant decrease their weight. In addition young females born from treated mothers showed significant decrease in the weight of reproductive system, diameter of ovaries and diameter of oviducts. Also, significant decrease was noticed in the level of FSH, LH and Estradiol level in the experimental group.Conclusion: Consuming of Achillea millifolium extract during pregnancy will produce bad effect on the pregnancy out come in addition to bad effect on the reproductive system of the female offspring.

Genetic Diversity and Inbreeding in a Captive Population of the North Persian Leopard (Panthera pardus saxicolor L.)

Information on the degree of inbreeding is very important in the effective management of captive populations of animals in zoos. For the North Persian leopard (Panthera pardus saxicolor), in particular, no report on this aspect is available. This study evaluated the effect of inbreeding on fitness traits and the possible occurrence of purging in a captive population of the leopard based on pedigree records of the Australasian Regional Association of Zoological Parks and Aquaria covering the period 1955–2008. The significance of individual, sire or dam inbreeding on individual and litter fitness traits and litter size was analyzed using linear mixed models. Results showed that individual inbreeding significantly decreased survival at days 30 and 90 (weaning age) after birth, while litter inbreeding significantly decreased litter survival at days 7, 30 and 90. There was also a corresponding decrease in litter size when the dam was inbred. Purging of genetic load is possible with increased survival of the individual and litter when the dam was inbred. However, enhanced zoo management has to be considered with increased survival of individuals. Considering the unpredictable response of traits to inbreeding, designing breeding programs for captive populations should be geared toward maximizing genetic diversity and minimizing the rate of inbreeding.

Effects of chronic carbon monoxide exposure on fetal growth and development in mice.

BackgroundCarbon monoxide (CO) is produced endogenously, and can also be acquired from many exogenous sources: ie. cigarette smoking, automobile exhaust. Although toxic at high levels, low level production or exposure lends to normal physiologic functions: smooth muscle cell relaxation, control of vascular tone, platelet aggregation, anti- inflammatory and anti-apoptotic events. In pregnancy, it is unclear at what level maternal CO exposure becomes toxic to the fetus. In this study, we hypothesized that CO would be embryotoxic, and we sought to determine at what level of chronic CO exposure in pregnancy embryo/fetotoxic effects are observed.MethodsPregnant CD1 mice were exposed to continuous levels of CO (0 to 400 ppm) from conception to gestation day 17. The effect on fetal/placental growth and development, and fetal/maternal CO concentrations were determined.ResultsMaternal and fetal CO blood concentrations ranged from 1.12- 15.6 percent carboxyhemoglobin (%COHb) and 1.0- 28.6%COHb, respectively. No significant difference was observed in placental histological morphology or in placental mass with any CO exposure. At 400 ppm CO vs. control, decreased litter size and fetal mass (p < 0.05), increased fetal early/late gestational deaths (p < 0.05), and increased CO content in the placenta and the maternal spleen, heart, liver, kidney and lung (p < 0.05) were observed.ConclusionsExposure to levels at or below 300 ppm CO throughout pregnancy has little demonstrable effect on fetal growth and development in the mouse.

Role of iodine in diiodomethyl-p-tolylsulfone induced reproductive toxicity in rats: Proposed mode of action

The biocide diiodomethyl-p-tolylsulfone (DIMPTS) caused dystocia, decreased neonatal survival and hypothyroidism in rat reproduction studies resembling the effects caused by iodine. One molecule of DIMPTS contains two iodine moieties that are hydrolyzed upon ingestion and systemically absorbed, suggesting iodine toxicity as a probable mode of action for the effects observed in rats. This study compared the effects induced by DIMPTS and an equimolar concentration of its de-iodinated analogue, methyl-p-tolylsulfone (MPTS). Groups of 20 female Sprague Dawley rats were fed diets supplying 80mg DIMPTS/kg/day, 32mg MPTS/kg/day or control feed from prior to breeding through lactation and gonadal function, mating performance, conception, gestation, parturition, lactation, survival, growth and development of pups evaluated through postnatal day 7. Serum thyroid hormones and iodine levels in milk and sera were also determined. Females given DIMPTS had increased incidence of vulvar discharge and dystocia, decreased litter size, decreased body weights and feed consumption, increased thyroid weights, thyroid follicular cell hypertrophy with decreased colloid, decreased triidothyronine, and increased thyroid stimulating hormone levels. DIMPTS pups had decreased neonatal survival and body weights. These effects were associated with elevated levels of iodine in milk and sera. In contrast, MPTS did not produce similar effects in adult females or their offspring. These data support the hypothesis that the dystocia, altered neonatal survival and hypothyroidism following repeated dietary administration of DIMPTS were due to excessive iodine released from DIMPTS during absorption and metabolism.

Vitamin K requirement and reproduction in bromadiolone‐resistant Norway rats

Nucleotide polymorphisms in the VKORC1 gene can be linked to anticoagulant rodenticide resistance in Norway rats (Rattus norvegicus Berkenhout). This provides a fitness advantage to rats exposed to anticoagulant actives, but may also cause fitness costs. The vitamin K requirement and reproductive parameters of bromadiolone-resistant rats (Westphalian resistant strain; VKOR variant Tyr139Cys) and bromadiolone-susceptible Norway rats were compared. At vitamin K deficiency, blood clotting times increased in all homozygous resistant males within 8 days and in 80% of homozygous resistant females within 15 days. There was little effect on blood clotting in heterozygous males and no effect in heterozygous females and VKOR wild-type individuals. Litter size was about 20% higher in sensitive pairs compared with resistant pairs. Testes growth, male gonad weight, sperm motility and testis cell concentration were unaffected by the mutation. The VKOR variant Tyr139Cys causes considerable physiological cost in Norway rats in terms of vitamin K requirement and reproduction. This may affect the distribution and spread of resistant individuals in the wild. Decreased litter size of resistant parents seems to be due to lowered female reproductive performance, as there was no significant effect of the mutation on any aspects of male reproduction considered, but this requires further study.

A more efficient method to generate null mutants using Hprt-Cre with floxed alleles

Purpose The generation of nonviable homozygous null mouse embryos from heterozygote null/+ breedings can be highly resource consuming, with only 25% of the embryos in the litter being null mutants. We hypothesized that (1) we could double the number of homozygous null mouse embryos in a litter without reducing litter size using Hypoxanthine-guanine phosphoribosyltransferase-Cre (Hprt)-Cre (which is active in the female germ line at the time of fertilization), and (2) these homozygous null mutants would be identical to mutants generated through traditional null/+ breedings. Methods To test this hypothesis, we used a conditional allele Fgfr2IIIb flox . This allele when recombined is identical to the Fgfr2IIIb null allele. An F1 generation of Fgfr2IIIb rec/+ ; Hprt Cre/+ females was created by mating Fgfr2IIIb +/+ ; Hprt cre /cre females to a Fgfr2IIIb flox/flox male. The F1 females were then mated to a Fgfr2IIIb flox/flox male. F2 embryos were genotyped, and the morphology and histology of the lungs, intestine, limbs, and brain were analyzed. Results The Hprt-Cre mating strategy results in 51% of pups being genotypic homozygous null embryos (85/166) vs 23% for the standard null/+ approach (38/167). These embryos did not express the Fgfr2IIIb transcript and were phenotypically identical to null embryos generated through standard null/+ breedings. Conclusions The Hprt-Cre mating strategy increases the number of homozygous mutant embryos in a litter without decreasing litter size. Embryos generated through this approach are phenotypically identical to those from standard heterozygous breedings. We recommend this approach to investigators using a model system that relies on the generation of homozygous null embryos.

Effect of empty uterine space on birth intervals and fetal and placental development in pigs

A substantial loss of embryos occurs between Days 30 and 40 of pregnancy in the pig under crowded intrauterine conditions, but it is not clear whether this loss affects the growth of adjacent conceptuses. Birth intervals are known to increase with decreasing litter size, but the factors responsible are unknown. Two possibilities are that increased birth weight associated with reduced litter size and the empty uterine space and resulting constricted uterine regions that occur in pigs with small litters may impair piglet delivery. To address these, pregnant gilts were laparotomized on Day 35 of pregnancy and one or two fetuses were manually crushed through the uterine wall on the ovarian or cervical end of each uterine horn to create an empty uterine space behind or in front of the litter of piglets, respectively, in relation to the route of delivery from the uterus. A subset of gilts was slaughtered at 105 days of gestation to confirm that the empty uterine spaces were successfully created and to determine their effects on placental and fetal weights of adjacent conceptuses. At slaughter, the lengths of all externally visible empty constricted regions of the uterus were measured. The uterine horns were opened and the lengths of each placenta were measured from the umbilicus toward the ovary and toward the cervix to assess whether placentas developed symmetrically, and then each fetus and placenta was weighed. Fetal crushing successfully created constricted empty uterine regions on the ovarian and cervical ends of the uterine horns. Ovarian-side placental lengths were greater than cervical-side for conceptuses adjacent to fetuses crushed on the ovarian end of the horn. Cervical-side placental lengths were greater than ovarian-side for conceptuses adjacent to fetuses crushed on the cervical end. Both placental and fetal weights were greater (10% and 6%, respectively, P < 0.05) for conceptuses adjacent to crushed fetuses compared to nonadjacent conceptuses. Remaining gilts were farrowed to determine the effect of litter size, average birth weights, and treatment on birth intervals of piglets, which were monitored using 24-h video surveillance. The negative association between number of piglets born alive and average birth interval was confirmed and was not explained by litter size-induced reduction in litter average birth weights. Birth intervals and stillbirth rate did not differ between cervically- and ovarian-treated gilts. These results indicate that conceptus loss on Day 35 of gestation can benefit the growth of adjacent placentas and fetuses, but the benefit is small. Increased average birth weight and the presence of empty uterine space that occurs when litter size is reduced does not fully explain the effect of litter size on birth intervals.

SPP1 (Osteopontin) and SPARC (Osteonectin) May Interact Developmentally During Mouse Pregnancy.

Secreted phosphoprotein 1 (SPP1, osteopontin) is an extracellular matrix (ECM) protein that binds integrins to affect cell-cell and cell-matrix interactions including adhesion, migration, proliferation and survival. Secreted-protein-acidic-and-rich-in-cysteine (SPARC, osteonectin) is a calcium-binding matricellular glycoprotein known to regulate ECM interaction during tissue remodeling and repair. We developed a Spp1-/-/Sparc-/- double null mouse in which 50% fewer pups are present at birth than are found in utero on days 18-20 of gestation due to postpartum maternal cannibalization of the pups, suggesting that these pups are stillborn or exhibit severe birth defects. Indeed, hemorrhages were observed prominently in lower right limbs and distal region of the tail in many embryos; in a few embryos, hemorrhages were present the intestine and right foreheads. In order to gain insight into the developmental abnormalities and decreased litter sizes seen in double null litters, we evaluated the expression of both Spp1 and Sparc in the mouse uterus throughout pregnancy. Ten-week old outbred CD-1 female mice were mated to an intact male of the same strain (copulatory plug = Day 1 of gestation). Pregnant females were sacrificed and uteri collected on Day 4, 4.5, 5, 9, 10, 11, 12, and 16 of pregnancy. Cell-specific expression of Spp1 and Sparc mRNA in serial sections of mouse uteri was determined by radioactive in situ hybridization analysis. On Day 4 of pregnancy, Spp1 was expressed in central cells of the inner cell mass (ICM) of the embryo, in scattered immune cells in uterine stroma, and in luminal epithelium (LE) directly contacting the embryo within the implantation chamber. LE expression within the implantation chamber was absent by Days 4.5-5 of pregnancy, but remained in LE adjacent to the implantation chamber and in interimplantation sites, suggesting that Spp1 may be involved in adhesion during the initial phase of embryo attachment to the LE, but subsequently must be down-regulated at sites of attachment to allow embryo invasion. Sparc was expressed diffusely in the uterine stroma, in peripheral cells of the ICM, and was not expressed in LE through Days 4.5-5. When we utilized a model of delayed implantation to determine the effect of nidatory estrogen, localization of Spp1 and Sparc was identical to that of pregnancy. On Day 9 of gestation, Spp1 was expressed by uterine natural killer (NK) cells and LE, whereas Sparc was expressed by decidual cells and LE. On Day 10, NK cells and LE continued to express Spp1, while Sparc was localized to the stroma directly beneath the LE. On Day 12, Spp1 was also expressed by trophoblast giant cells, and Sparc was expressed in the Reichert's Membrane adjacent to the trophoblast giant cells. By Day 16 of pregnancy, both Spp1 and Sparc were expressed in adjacent but non-overlapping regions of developing fetal bone and cartilage. Because Spp1 and Sparc often have antagonistic roles during tissue remodeling and are localized to adjacent but different cell types during mouse pregnancy, we hypothesize that simultaneous deletion of both Spp1 and Sparc leads to disruption of cell-cell, cell-matrix and inter-tissue communication essential to normal conceptus development that is not observed when the genes are deleted individually. This study was supported by NIH grants R01 CA90920 and RO1 CA137091. (platform)

EFFECT OF BIRTH WEIGHT AND LITTER SIZE ON GROWTH AND MORTALITY IN RABBITS

Two experiments were performed with Pannon White rabbits. In the first experiment 50 litters were formed with 6, 8 or 10 rabbits of different birth weight in equal ratios (n = 380, between 39 and 70g). In the second experiment 60 litters of 6, 8 or 10 rabbits were formed (n = 456), each litter consisting of rabbits of a single weight group only (small: 39 to 43g; medium: 53 to 56 g; large: 63 to 70 g). With increasing birth weight and decreasing litter size, mortality in the suckling rabbits decreased and daily weight gain of kits and weight of rabbits up to 10 weeks of age increased significantly. These effects were weaker in experiment 2. In the extreme groups used in the experiments (10 small kits and 6 large kits) the following results were obtained: mortality between birth and 21 days was 35.3 and 8.1 % in experiment 1 and 18.0 and 5.6 % in experiment 2, daily weight gain of kits between birth and 21 days was 9.2 and 18.5 g in experiment 1 and 10.8 and 16. 7 g in experiment 2, and body weight at 10 weeks of age was 1.90 and 2.58 kg in experiment 1 and 2.11 and 2.45 kg in experiment 2. In conclusion, intra-litter homogenisation of birth weight markedly reduced mortality in small rabbits and standard deviation in live weight within litters.

Reversibility of the effects of the chemotherapeutic regimen for non-Hodgkin lymphoma, cyclophosphamide, doxorubicin, vincristine, and prednisone, on the male rat reproductive system and progeny outcome

The chemotherapeutic agents used to treat non-Hodgkin lymphoma, cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP), have adverse effects on male reproductive function and progeny outcome. To determine the reversibility of these effects, male rats received a CHOP treatment mimicking human exposure. CHOP reduced testicular and epididymal weights; these remained decreased after 9 weeks recovery. This treatment also decreased testicular sperm number and increased spermatozoal DNA damage. Although sperm production returned to control values after 9 weeks recovery, DNA damage persisted. Decreased litter size, and increased pre- and post-implantation losses were observed among litters sired by CHOP-exposed males. Litter size and pre-implantation loss returned to control within 3 weeks post-treatment and post-implantation loss by 6 weeks. Thus, effects of CHOP on progeny outcome were reversed 9 weeks post-treatment, although germ cell DNA breaks remained elevated. These data suggest that the ability to sire viable progeny may not be a sensitive measure of spermatozoal quality in rats.

Maternal responses to daily maternal porcine somatotropin injections during early-mid pregnancy or early-late pregnancy in sows and gilts1

Piglet neonatal survival and postnatal growth and efficiency are positively related to birth weight. In gilts, daily maternal porcine ST (pST) injections from d 25 to 100 (term approximately 115 d), but not d 25 to 50, of pregnancy increase progeny birth weight. Daily maternal pST injections from d 25 to 50 increase fetal weight at d 50 in gilts and sows. We therefore hypothesized that daily pST injections from d 25 to 100, but not d 25 to 50, of pregnancy would increase birth weight similarly in both parities. Landrace x Large White gilts and sows were uninjected (controls) or were injected daily with pST (gilts: 2.5 mg/d; sows: 4.0 mg/d, each approximately 15 microg of pST/kg per day) from d 25 to 50 or 100 of pregnancy. Litter size and BW were recorded at birth, midlactation, and weaning. Dams were followed through the subsequent mating and pregnancy. Maternal pST injections from d 25 to 100, but not d 25 to 50, increased mean piglet birth weight by 11.6% in sows (P <or= 0.001) and by 5.6% in gilts (P = 0.008). Both pST treatments decreased litter size by approximately 0.6 live-born piglets (each P <or= 0.025). In sows, maternal pST treatment from d 25 to 100 increased culls at weaning (P = 0.037). In remated dams, prior treatments did not affect (P > 0.1) the weaning-remating interval, conception rate, or subsequent litter size. Greater pST-induced birth weight increases in sows than in gilts may mean that underlying metabolic or placental mechanisms for pST action are constrained by maternal competition for nutrients in rapidly growing gilts.

Effects of Concrete and Wood Building Environments on Pregnant Dams and Embryo-Fetal Development in Rats.

We have recently reported that the continuous exposure of rats to a concrete building environment under cool temperatures had adverse effects on general health parameters and embryo-fetal development. This study examined to compare the potential effects of concrete and wood building environments on pregnant dams and embryo-fetal development in rats. Groups of 10 mated females were exposed to polycarbonate (control), concrete, or wood cages from gestational days (GD) 0 to 20 under cool temperatures (11.9∼12.3°C). All the females underwent a caesarean section on GD 20, and their fetuses were examined for any morphological abnormalities. The temperatures in the cages were similar in all groups but the relative humidity in the concrete and wood groups were higher than in the control group. The concentration of volatile organic compounds in the wood group was higher than in the control group. In the concrete group, maternal effects manifested as an increase in the incidence of clinical signs, a lower body weight, and a decrease in the thymus and ovary weights. Developmental effects included increased post-implantation loss and decreased litter size. Infrared thermal analysis showed that the skin temperature of the rats in the concrete group was lower than that in the control group. In contrast, there were no exposure-related adverse effects on the maternal and developmental parameters in the wood group. Overall, the exposure of pregnant rats to a concrete building environment under cool temperatures has adverse effects on the clinical signs, body weight, skin temperature, organ weight, and embryo-fetal development. On the other hand, exposure to a wood building environment does not have any adverse effects in rats.

Perinatal exposure of rats to Bisphenol A affects the fertility of male offspring

Aims The exposure to endocrine disruptor (ED) induces functional and behavioral abnormalities associated with reproduction. Humans are ubiquitously exposed to Bisphenol A (BPA), an ED, as it leaches from polycarbonate plastics into their contents. The aim of the present study was to determine the effect of perinatal exposure of male rats to BPA on fertility parameters and perturbations in the expression of testicular steroid receptors (SRs) in adult F 1 offspring. These effects were studied in adult males of the F 2 and F 3 generations to determine the vertical transmission of BPA exposure. Main methods Pregnant female rats (F 0) were gavaged with either BPA (1.2 and 2.4 μg/kg bw), a vehicle control or positive control with Diethylstilbestrol (10 μg/kg bw) during the perinatal period. Adult F 1 males were subjected to fertility assessment by mating with unexposed females. The reproductive functions of the subsequent F 2 and F 3 litters were investigated in a similar manner. Immunohistochemical localization of SRs was carried out in the testes of F 1, F 2 and F 3 generation adult rats. Key findings A significant increase in post implantation loss and a decrease in litter size and sperm count and motility were observed in the F 1 male offspring. A reduction in the testicular expression profile of SRs was observed. These effects were very prominent in the subsequent F 2 and F 3 generations. Significance Perinatal exposure to environmentally relevant doses of BPA affects the male germ line, leading to impairments in the fertility of F 1 male offspring and their subsequent F 2 and F 3 generations.

Neonatal exposure of male rats to Bisphenol A impairs fertility and expression of sertoli cell junctional proteins in the testis

Background Sertoli cell junctional proteins (SCJP) (viz. adhesion, gap and tight junctions) are important for spermatogenesis and perturbations in expression of these proteins are associated with impairments in process of sperm production. Bisphenol A (BPA) is an endocrine disrupter that has been associated with impaired spermatogenesis. However the mechanistic basis of impaired spermatogenesis is unknown, whether BPA is a Sertoli cell toxicant has not yet been fully investigated. Objectives The present study was undertaken to decipher the effects of neonatal exposure of male rats to BPA on fertility and its effect on the testicular expression of SCJP during development. Methods Neonatal male rats were s.c. injected with BPA at doses ranging from 0.6 to 10 μg/rat (100–1600 μg/kg bw of BPA) on post-natal days (PNDs) 1–5, and controls received vehicle. Diethylstilbestrol (DES) was used as a positive control. Male fertility was assessed during adulthood and the lowest dose of BPA that was most effective at impairing fertility was determined. Immunohistochemical localization for Connexin 43 (Cx-43, gap junctional), Zona Occludin-1 (ZO-1, tight junctions) and N-cadherin (adherens junction) was carried out on testicular tissue sections obtained from PNDs 15, 30, 45 and 90 of rats exposed to lowest dose of BPA that impaired fertility. Results Females mated with male rats that were exposed neonatally to various concentrations of BPA showed a significant increase in post-implantation loss and a decrease in litter size. There were significant changes in sperm count along with hormonal imbalances in the rats exposed neonatally to BPA. The 2.4 μg dose (400 μg/kg bw) of BPA was determined as the lowest dose that was capable of impairing male fertility. A significant reduction in the expression of Cx-43 (PND 45 and 90) and increases in the expression of N-cadherin (PND 45 and 90) and ZO-1 (PND 90) were observed in the testes of rats exposed neonatally to effective dose of BPA. Interestingly, there was an altered expression pattern of Cx43 amongst the sloughed cells in the testes of the experimental rats as compared to controls. Conclusion Neonatal exposure of BPA to rats impairs their fertility and has the potential to induce perturbations in SCJP. These perturbations may be one of the contributing factors that lead to impairments in spermatogenesis in the exposed animals and can be used as potential biomarkers to study BPA-induced effects on testes.

Proteomic analysis of proteins differentially expressed in uterine lymphocytes obtained from wild‐type and NOD mice

Non-obese diabetic (NOD) mice exhibit impaired fertility and decreased litter size when compared to wild type (WT) mice. However, it is unclear why allogeneic pregnant NOD mice are prone to spontaneous embryo loss. Herein, two-dimensional gel electrophoresis (2-DE) and mass spectrometry (MS) were used to detect differentially expressed proteins in the uterine lymphocytes isolated from these mice and WT BALB/c controls. We found 24 differentially expressed proteins. The differential expression of 10 of these proteins was further confirmed by Western blot analysis. Out of the 24 identified proteins, 20 were expressed in uterine lymphocytes of WT mice at a level at least 2 times higher than in NOD mice, whereas 4 were down-regulated. Western blot analysis confirmed that 8 proteins were up-regulated and 2 proteins were down-regulated in WT mice compared with NOD mice, consistent with the results of 2-DE and MS. Additionally, most of the highly expressed proteins in WT uterine lymphocytes were expressed at a significantly lower level in the corresponding splenic group (17/20). These results suggest that up-regulated expression of these proteins may be specific to uterine lymphocytes. Reported functions of the highly expressed proteins affect key functions during pregnancy, including cell movement, cell cycle control, and metabolisms. Finally, we analyzed the constitutional ratio of CD3(+) and CD49b(+) cells in the isolated lymphocytes by flow cytometry. Our results suggest that the differentially expressed proteins may participate in the modulation of embryo implantation and early-stage development of embryos, and subsequently influence pregnancy outcome.

Chronic dietary exposure to a low-dose mixture of genistein and vinclozolin modifies the reproductive axis, testis transcriptome, and fertility.

BackgroundThe reproductive consequences and mechanisms of action of chronic exposure to low-dose endocrine disruptors are poorly understood.ObjectiveWe assessed the effects of a continuous, low-dose exposure to a phytoestrogen (genistein) and/or an antiandrogenic food contaminant (vinclozolin) on the male reproductive tract and fertility.MethodsMale rats were exposed by gavage to genistein and vinclozolin from conception to adulthood, alone or in combination, at low doses (1 mg/kg/day) or higher doses (10 and 30 mg/kg/day). We studied a number of standard reproductive toxicology end points and also assessed testicular mRNA expression profiles using long-oligonucleotide microarrays.ResultsThe low-dose mixture and high-dose vinclozolin produced the most significant alterations in adults: decreased sperm counts, reduced sperm motion parameters, decreased litter sizes, and increased post implantation loss. Testicular mRNA expression profiles for these exposure conditions were strongly correlated. Functional clustering indicated that many of the genes induced belong to the “neuroactive ligand-receptor interactions” family encompassing several hormonally related actors (e.g., follicle-stimulating hormone and its receptor). All exposure conditions decreased the levels of mRNAs involved in ribosome function, indicating probable decreased protein production.ConclusionsOur study shows that chronic exposure to a mixture of a dose of a phytoestrogen equivalent to that in the human diet and a low dose—albeit not environmental—of a common anti-androgenic food contaminant may seriously affect the male reproductive tract and fertility.

Effects of gestational exposure to chlorpyrifos on implantation and neonatal mice

Exposure to some organophosphate (OP) compounds during pregnancy has been associated with adverse health consequence on both the mother and the offspring. The aim of the study was to evaluate the effect of exposure to chlorpyrifos (CPF) during gestation on implantation and on some neonatal parameters in mice. Twenty one virgin Swiss albino mice divided into 3 groups of 7 mice each served as subjects for this study. Mice in group 1 were dosed with corn oil (control), while those in groups 2 and 3 were exposed to CPF at a dose of 15.9 mg/kg (~15% LD50) and 21.2 mg/kg (~20% LD50), respectively. All the dams were dosed between gestation days (GD) 6 - 15 and monitored for signs of toxicity and gestation length. At birth, the litter size and weight, and the anogenital distance of the pups were measured. The pups were evaluated for physical characteristics and death. The dams were sacrificed at postnatal day 22, and the uterine horns evaluated for number of implantation sites. The results showed a significant decrease in the litter size and weight, and anogenital distance in pups exposed to CPF in utero compared to the control. In addition, all the pups prenatally exposed to CPF were born weak and died few days postpartum. A dose-dependent increase in percentage postimplantation loss was observed in mice dosed with CPF. In conclusion, exposure of pregnant mice to CPF caused increased gestation length, and postimplantation loss, decreased litter size and weight, survivability and anogenital distance.

Variant-Specific Immunity to Plasmodium berghei in Pregnant Mice

We have investigated the immunological basis of pregnancy-related Plasmodium berghei recrudescence in immune mice with substantial preexisting immunity. Specifically, we examined the relevance of this experimental model to the study of pregnancy-associated malaria (PAM) caused by P. falciparum in women with substantial preexisting protective immunity. We used mice with immunity induced prior to pregnancy and employed flow cytometry to assess their levels of immunoglobulin G (IgG) recognizing antigens on the surfaces of infected erythrocytes (IEs) in plasma. After immunization, the mice did not possess IgG specific for antigens on IEs obtained during pregnancy-related recrudescence but they acquired recrudescence-specific IgG over the course of several pregnancies and recrudescences. In contrast, levels of antibodies recognizing IEs from nonpregnant mice did not increase with increasing parity. Furthermore, maternal hemoglobin levels increased and pregnancy-related parasitemia decreased with increasing parity. Finally, parasitemic mice produced smaller litters and pups with lower weights than nonparasitemic mice. Taken together, these observations suggest that levels of antibodies specific for recrudescence-type IEs are related to the protection of pregnant mice from maternal anemia, low birth weight, and decreased litter size. We conclude that the model replicates many of the key parasitological and immunological features of PAM, although the P. berghei genome does not encode proteins homologous to the P. falciparum erythrocyte membrane protein 1 adhesins, which are of key importance in P. falciparum malaria. The study of P. berghei malaria in pregnant, immune mice can be used to gain significant new insights regarding malaria pathogenesis and immunity in general and regarding PAM in particular.

Multigenerational effects in deer mice ( Peromyscus maniculatus) exposed to hexahydro-1,3,5-trinitroso-1,3,5-triazine (TNX)

Contamination by hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) has been identified at areas of explosive manufacturing, processing, storage, and usage. Anaerobic conversion of RDX to N-nitroso metabolites (hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX), hexahydro-1,3-dinitroso-5-nitro-1,3,5-triazine (DNX), and hexahydro-1,3,5-trinitroso-1,3,5-triazine (TNX)) has been demonstrated in the environment and in gastrointestinal tracts of mammals in vivo. Thus, potential exists for exposure to these N-nitroso compounds. While exposed to TNX via drinking water ad libitum, deer mice ( Peromyscus maniculatus) were bred in three generations to produce cohorts F1A-D, F2A-B, and F3A. TNX was administered at four exposure levels: control (0 μg L −1), 10 μg L −1, 100 μg L −1, and 1000 μg L −1. Endpoints investigated include: offspring production, offspring survival, offspring weight gain, and offspring organ weights. TNX exposure decreased litter size and increased postpartum mortality of offspring at the highest exposure level.