Prenatal development of domestic and laboratory mammals: growth curves, external features and selected references

Validation of Selected MicroRNA Transcriptome Data in the Bovine Corpus Luteum during Early Pregnancy by RT-qPCR

In cattle, the corpus luteum (CL) is pivotal in maintaining early pregnancy by secreting progesterone. To establish pregnancy, the conceptus produces interferon-τ, preventing luteolysis and initiating the transformation of the CL spurium into a CL verum. Although this transformation is tightly regulated, limited data are available on the expression of microRNAs (miRNAs) during and after this process. To address this gap, we re-analyzed previously published RNA-Seq data of CL from pregnant cows and regressed CL from non-pregnant cows. This analysis identified 44 differentially expressed miRNAs. From this pool, three miRNAs-bta-miR-222-3p, bta-miR-29c, and bta-miR-2411-3p-were randomly selected for relative quantification. Using bovine ovaries (n = 14) obtained from an abattoir, total RNA (including miRNAs) was extracted and converted to cDNA for RT-qPCR. The results revealed that bta-miR-222-3p was downregulated (p = 0.016) in pregnant females compared to non-pregnant cows with regressed CL. However, no differences in miRNA expression were observed between CL of pregnant and non-pregnant cows for bta-miR-29c (p > 0.32) or bta-miR-2411-3p (p > 0.60). In silico prediction approaches indicated that these miRNAs are involved in pathways regulating pregnancy maintenance, such as the VEGF- and FoxO-signaling pathways. Additionally, their biogenesis is regulated by GABPA and E2F4 transcription factors. The validation of selected miRNA expression in the CL during pregnancy by RT-qPCR provides novel insights that could potentially lead to the identification of biomarkers related to CL physiology and pregnancy outcome.

Prenatal post-implantation development of collared peccaries (Pecari tajacu Linnaeus, 1758)

Given the importance of information on intrauterine development in diagnosing anomalies in the gestational development of the species for the development of assisted reproduction technologies as well as understanding the autonomy and responsiveness of the newborn, the aim of the present study was to describe the external morphology of collared peccary conceptuses. For this study, two conceptuses were used per gestational age of 25-120 days post-copulation (dpc) and neonates with 145 dpc, totalling 22 animals. Females were euthanised, and embryos/foetuses were examined, measured, and photographed. During the first third of the gestational period (25-50 dpc, n = 8), a marked body curvature, brain vesicles, somites, internal organs, placid lens, auricular protrusion and limb buds are noted. In the second third of the gestational period (51-100 dpc, n = 10), foetuses lose their body curvature, displaying greater anatomical definition, including skeletal, external ears, nostrils, eyelids and tactile hair formation and cranial suture closure. In addition, dorsal scent gland and genital tubercle differentiation were visualized at 50 days post-copulation. In the third of the gestational period (101-145 dpc, n = 4), the organs become completely formed, alongside skin darkening, eyelid opening, dental eruption, dorsal odorous gland development, sexual organ externalization, and fanero attachment development. These data allowed for the construction of a prenatal growth curve, providing comparative anatomy information for ungulates and further contributing towards rational reproductive management and reproductive biotechnologies for this species.

Differential Development of the Chordae Tendineae and Anterior Leaflet of the Bovine Mitral Valve

There is increasing evidence that some adult mitral valve pathologies may have developmental origins involving errors in cell signaling and protein deposition during valvulogenesis. While early and late gestational stages are well-documented in zebrafish, chicks, and small mammalian models, longitudinal studies in large mammals with a similar gestational period to humans are lacking. Further, the mechanism of chordae tendineae formation and multiplication remains unclear. The current study presents a comprehensive examination of mitral anterior leaflet and chordae tendineae development in a bovine model (a large mammal with the same gestational period as humans). Remarkably distinct from small mammals, bovine development displayed early branched chordae, with increasing attachments only until birth, while the anterior leaflet grew both during gestation and postnatally. Chordae also exhibited accelerated collagen deposition, maturation, and crimp development during gestation. These findings suggest that the bovine anterior leaflet and chordae tendineae possess unique processes of development despite being a continuous collagenous structure and could provide greater insight into human valve development.

Weak coupling between energetic status and the timing of reproduction in an Arctic ungulate

Bioenergetic constraints are the ultimate determinant of the timing of reproduction, and seasonal breeding is consequently a widely observed trait. Consistent with this, attention has focused on plasticity in reproductive phenology conceptualized as a response to concomitant advances in the phenology of the environmental energy supply caused by climate change. Few studies, however, have directly compared timing of reproduction with energetic status in free-living wild animals. Here we demonstrate that neither body mass nor adiposity are strong proximate predictors of date of conception in wild reindeer (Rangifer tarandus). Weak coupling between energetic status and the phenology of reproduction accounts for the increasing discrepancy between the phenology of forage (energy supply) and the phenology of reproduction (energy demand) observed across the last 2-4 decades in two populations of this species. The results emphasise that phenological plasticity is not a passive response to changes in energy supply but derives from the way in which environmental factors interact with the core control mechanisms that govern timing. Central in this respect is integration, within the rheostatic centres of the hypothalamus, of information on nutritional status with the circannual life-history calendar.

The Clockwork Embryo: Mechanisms Regulating Developmental Rate

Organismal development requires the reproducible unfolding of an ordered sequence of discrete steps (cell fate determination, migration, tissue folding, etc.) in both time and space. Here, we review the mechanisms that grant temporal specificity to developmental steps, including molecular clocks and timers. Individual timing mechanisms must be coordinated with each other to maintain the overall developmental sequence. However, phenotypic novelties can also arise through the modification of temporal patterns over the course of evolution. Two main types of variation in temporal patterning characterize interspecies differences in developmental time: allochrony, where the overall developmental sequence is either accelerated or slowed down while maintaining the relative duration of individual steps, and heterochrony, where the duration of specific developmental steps is altered relative to the rest. New advances in in vitro modeling of mammalian development using stem cells have recently enabled the revival of mechanistic studies of allochrony and heterochrony. In both cases, differences in the rate of basic cellular functions such as splicing, translation, protein degradation, and metabolism seem to underlie differences in developmental time. In the coming years, these studies should identify the genetic differences that drive divergence in developmental time between species.

Characterization of the Abracl-Expressing Cell Populations in the Embryonic Mammalian Telencephalon

Abracl (ABRA C-terminal-like protein) is a small, non-typical winged-helix protein that shares similarity with the C-terminal domain of the protein ABRA (Actin-Binding Rho-Activating protein). The role of Abracl in the cell remains elusive, although in cancer cells, it has been implicated in proliferation, migration and actin dynamics. Our previous study showed that Abracl mRNA was expressed in the dividing cells of the subpallial subventricular zone (SVZ), in the developing cortical plate (CP), and in the diencephalic SVZ; however, the molecular identities of the Abracl-expressing cell populations were not defined in that work. In this study, we use double immunofluorescence to characterize the expression of Abracl on sections of embryonic murine (E11.5-E18.5) and feline (E30/31-E33/34) telencephalon; to this end, we use a battery of well-known molecular markers of cycling (Ki67, Ascl1, Dlx2) or post-mitotic (Tubb3, Gad65/67, Lhx6 and Tbr1) cells. Our experiments show that Abracl protein has, compared to the mRNA, a broader expression domain, including, apart from proliferating cells of the subpallial and diencephalic SVZ, post-mitotic cells occupying the subpallial and pallial mantle (including the CP), as well as subpallial-derived migrating interneurons. Interestingly, in late embryonic developmental stages, Abracl was also transiently detected in major telencephalic fiber tracts.

Development and Degeneration of the Intervertebral Disc-Insights from Across Species

Back pain caused by intervertebral disc (IVD) degeneration has a major socio-economic impact in humans, yet historically has received minimal attention in species other than humans, mice and dogs. However, a general growing interest in this unique organ prompted the expansion of IVD research in rats, rabbits, cats, horses, monkeys, and cows, further illuminating the complex nature of the organ in both healthy and degenerative states. Application of recent biotechnological advancements, including single cell RNA sequencing and complex data analysis methods has begun to explain the shifting inflammatory signaling, variation in cellular subpopulations, differential gene expression, mechanical loading, and metabolic stresses which contribute to age and stress related degeneration of the IVD. This increase in IVD research across species introduces a need for chronicling IVD advancements and tissue biomarkers both within and between species. Here we provide a comprehensive review of recent single cell RNA sequencing data alongside existing case reports and histo/morphological data to highlight the cellular complexity and metabolic challenges of this unique organ that is of structural importance for all vertebrates.

Pentalogy of Cantrell in Two Neonate Littermate Puppies: A Spontaneous Animal Model Suggesting Familial Inheritance

Developmental anomalies are an important cause of stillbirth and early perinatal death in companion animals. Many of these disorders remain poorly understood and provide an opportunity as a spontaneous animal model for human disease. Pentalogy of Cantrell is a rare congenital syndrome described in human neonates. It is a ventral midline closure defect with a proposed familial inheritance in humans. This syndrome involves five defects, including the thoracoabdominal wall, sternal, diaphragmatic, pericardial and cardiac malformations. Diverse expressions of these defects have been described in humans and sporadically in domestic animals. This severe syndrome commonly harbors a poor prognosis, posing an ethical and surgical dilemma. To better understand this syndrome and its presentation in dogs, we describe two rare cases of Pentalogy of Cantrell in a litter of papillon dogs. The affected puppies had anomalies compatible with the Pentalogy of Cantrell, including thoracoabdominal schisis, ectopia cordis, sternal cleft, pericardial agenesis, and diaphragmatic defects. The diagnosis was confirmed by advanced imaging (computed tomography) and postmortem examinations. The family history of this litter was explored and other cases in domestic animals were reviewed. This is the first report of the complete Pentalogy of Cantrell with ectopia cordis in the dog and the only report on papillons. Similar to human cases, possible familial inheritance and suspected male gender bias were observed. Further research on this novel animal model, its pathogenesis and its hereditary basis, may be helpful in better understanding this rare developmental disorder.

Comparative embryogenesis in ungulate domesticated species

We compared embryogenesis of five species of domesticated even-toed and one odd-toed ungulate and used a phylogenetic framework to contextualize such comparison. Organ systems that occur relatively earlier in embryogenesis generally have more time to develop and therefore are found to be more mature at birth when compared to structures that appear later in development. We hypothesized that the less mature the animals' organs are at birth, the more they are susceptible to artificial selection. The horse had the most mature organs at birth, followed by cattle, reindeer, sheep/goat, and pig. This pattern of maturity could be observed almost during the entire development. Heterochronic shifts among species were observed only after fur starts to develop. Changes in the fur coloration are one of the first observable signs of domestication and the heterochrony of this trait may be related to the effects on neural crest-derived pigment cells by artificial selection. The six ungulate species also differ in the relative duration of their weaning period and the potential extent of its artificial shortening. We put all these traits in the context of their inherited evolutionary characteristics and artificial domestication process. Related to their altriciality, carnivoran domesticates, which also belong to Scrotifera, are less mature at birth than all domesticated ungulates. Although we detected clear character correlations to life history traits, it is impossible based on the present data, to trace specific exaptations to the domestication process. We hypothesize a deep time developmental penetration of adult characters into embryogenesis.

Bone development in offspring of pregnant rats treated with carbamazepine: Evaluation by three different methods

OBJECTIVE

This study was carried out to determine the effect of intrauterine carbamazepine (CBZ) exposure on fetal bone development during pregnancy.

METHODS

In the study, 24 female Wistar pregnant rats were used. Rats were 20 weeks old. They had an average body weight of 150-200 g. Pregnant rats were randomly selected and divided (n = 6) into a control group, low-dose CBZ (10 mg/kg/day) group, medium-dose CBZ (25 mg/kg/day) group, and high-dose CBZ (50 mg/kg/day) group. The ossification length (mm) and ossification area (mm² ) of the long bones of the fetuses in the experimental and control groups were calculated. The densities of alkaline phosphatase (AP) and tartrate-resistant acid phosphatase (TRAP) were analyzed. The ossification regions of the femurs of the fetuses were examined under a light microscope. Microstructural images of the femurs were evaluated with scanning electron microscope photographs. The densities of minerals involved in the ossification process were analyzed.

RESULTS

According to the results of the study, all three doses of CBZ caused loss of ossification areas, and it was observed that this bone loss also increased statistically significantly depending on the dose increase (p < .05). Calcium concentration decreased in the CBZ groups. When the electron microscope images were examined, it was determined that the cartilage matrix of the CBZ groups was thinned. In the histological evaluation of the groups, narrowing of the primary bone collar and smaller bone spicules in the ossification region compared to the control group were noted due to the increase in dose in the CBZ groups. In immunohistochemical staining, it was observed that the TRAP and AP expression values of the femurs were the lowest in the CBZ groups. These decreases were also statistically significant when compared with the control group.

SIGNIFICANCE

It was revealed with both microscopic and macroscopic findings that exposure to intrauterine CBZ negatively affected ossification and bone growth.

Ultrasound evaluation of fetal bone development in the collared (Pecari tajacu) and white-lipped peccary (Tayassu pecari)

The study of fetal development allows for evaluating the different strategies adopted by mammal species to maximize neonatal survival. Autonomous locomotion is fundamental for newborns to perform foraging activities and increases newborn survival from predation. In this study, we assess the gestational bone development of 53 collared (CP, Pecari tajacu) and 61 white-lipped (WLP, Tayassu pecari) peccaries, collected through the collaboration of subsistence hunters in the Amazon. The bone mineralization and biometry of the axial and appendicular skeleton were assessed by ultrasound examinations, and the timing of the main bone developmental events was calculated in relation to the total dorsal length (TDL) and the percentage of the total gestational period (GP). The first US signs of mineralization of the axial skeleton in CP and WLP were observed in fetuses with 3.4 cm (42 gestation days, 30% GPCP ) and 5.1 cm (51 gestation days, 32% GPWLP ). The early development of the appendicular skeleton was observed by the synchronic appearance of the mineralized scapula, humerus, radius, ulna, ilium, ischium, femur, tibia, and fibula at 36% GPCP (50 gestation days), and 35% GPWLP (56 gestation days). The pubis was mineralized in fetuses at 55% GPCP (75 gestation days) and 59% GPWLP (94 gestation days). The mineralization was observed in all autopod bones at 79% GPCP (109 gestation days) and 67% GPWLP (106 gestation days). All primary ossification centers in long bones of thoracic and pelvic limbs were mineralized in advanced fetuses (GPCP and GPWLP ≥75%). The mineralized patella was not observed in advanced fetuses in either species. Secondary ossification centers first appeared at the distal epiphysis of the femur in the CP (99 gestation days, 72% GPCP ) and the distal epiphysis of the radius, femur, and tibia in the WLP (106 gestation days, 67% GPWLP ). Advanced fetuses of CP and WLP presented 60% (15/25) and 68% (17/25) of the total secondary ossification centers observed present in the adult domestic pig, while newborns from the domestic pig presented 52% (13/25). The early intrauterine development of the skeletal system in both peccary species suggests a precocial development strategy, which likely correlates with neonatal ability to escape predators and reduces the dependence on parental care.

LincRNA#1 knockout alone does not affect polled phenotype in cattle heterozygous for the celtic POLLED allele

A long intergenic non-coding RNA (lincRNA#1) is overexpressed in the horn bud region of polled (hornless) bovine fetuses, suggesting a potential role in horn bud suppression. Genome editing was used to test whether the absence of this sequence was associated with the horned phenotype. Two gRNAs with high mutation efficiencies targeting the 5' and the 3' regions flanking the lincRNA#1 sequence were co-injected with Cas9 as ribonucleoprotein complexes into bovine zygotes (n = 121) 6 h post insemination. Of the resulting blastocysts (n = 31), 84% had the expected 3.7 kb deletion; of these embryos with the 3.7 kb deletions, 88% were biallelic knockouts. Thirty-nine presumptive edited 7-day blastocysts were transferred to 13 synchronized recipient cows resulting in ten pregnancies, five with embryos heterozygous for the dominant P_C POLLED allele at the POLLED locus, and five with the recessive pp genotype. Eight (80%) of the resulting fetuses were biallelic lincRNA#1 knockouts, with the remaining two being mosaic. RT-qPCR analysis was used to confirm the absence of lincRNA#1 expression in knockout fetuses. Phenotypic and histological analysis of the genotypically (P_Cp) POLLED, lincRNA#1 knockout fetuses revealed similar morphology to non-edited, control polled fetuses, indicating the absence of lincRNA#1 alone does not result in a horned phenotype.

Genoarchitectonic Compartmentalization of the Embryonic Telencephalon: Insights From the Domestic Cat

The telencephalon develops from the alar plate of the secondary prosencephalon and is subdivided into two distinct divisions, the pallium, which derives solely from prosomere hp1, and the subpallium which derives from both hp1 and hp2 prosomeres. In this first systematic analysis of the feline telencephalon genoarchitecture, we apply the prosomeric model to compare the expression of a battery of genes, including Tbr1, Tbr2, Pax6, Mash1, Dlx2, Nkx2-1, Lhx6, Lhx7, Lhx2, and Emx1, the orthologs of which alone or in combination, demarcate molecularly distinct territories in other species. We characterize, within the pallium and the subpallium, domains and subdomains topologically equivalent to those previously described in other vertebrate species and we show that the overall genoarchitectural map of the E26/27 feline brain is highly similar to that of the E13.5/E14 mouse. In addition, using the same approach at the earlier (E22/23 and E24/25) or later (E28/29 and E34/35) stages we further analyze neurogenesis, define the timing and duration of several developmental events, and compare our data with those from similar mouse studies; our results point to a complex pattern of heterochronies and show that, compared with the mouse, developmental events in the feline telencephalon span over extended periods suggesting that cats may provide a useful animal model to study brain patterning in ontogenesis and evolution.

The Tempo of Mammalian Embryogenesis: Variation in the Pace of Brain and Body Development

Why do some species develop rapidly, while others develop slowly? Mammals are highly variable in the pace of growth and development over every stage of ontogeny, and this basic variable - the pace of ontogeny - is strongly associated with a wide range of phenotypes in adults, including allometric patterns of brain and body size, as well as the pace of neurodevelopment. This analysis describes variation in the pace of embryonic development in eutherian mammals, drawing on a collected dataset of embryogenesis in fifteen species representing rodents, carnivores, ungulates, and primates. Mammals vary in the pace of every stage of embryogenesis, including stages of early zygote differentiation, blastulation and implantation, gastrulation, neurulation, somitogenesis, and later stages of basic limb, facial, and brain development. This comparative review focuses on the general variation of rapid vs. slow mammalian embryogenesis, with a focus on the pace of somite formation, brain vs. somatic development, and how embryonic pacing predicts later features of ontogeny.

Investigation of Toxoplasma gondii and Neospora caninum as cause of ovine abortion in affected flocks of Urmia, northwest of Iran

Toxoplasma gondii and Neospora caninum, two obligatory intracellular protozoan parasites, are important causes of neonatal mortality and abortion in farmed ruminants worldwide. Previously, protozoan abortions in small ruminants were attributed to T. gondii, but the role of N. caninum in these abortions was uncertain. The aim of this study was to investigate the role of T. gondii and N. caninum in ovine abortion in Urmia, northwest of Iran using a molecular method. Overall, 130 placenta and brain samples of aborted ovine foetuses were collected. Extracted DNA from placenta and CNS tissues of the aborted foetuses were analysed using PCR with primers specific for T. gondii and N. cani­num. The association of the frequency of T. gondii and N. caninum infection of aborted foetuses with age and breed in flocks was also studied. The results showed that out of the 130 examined ovine foetuses, 5.3 and 2.3 % were PCR-positive for T. gondii and N. caninum DNA, respectively. In this study, no significant differences were recorded relating to Toxoplasma and Neospora infection in different age groups in flocks and among sheep breeds included in the present study (P>0.05). The results of this study proved the importance of T. gondii and N. caninum as reasons of abortion in the studied area.

Porcine lymphotropic herpesvirus (Gammaherpesvirinae) DNA in free-living wild boars (Sus scrofa Linnaeus, 1758) in Brazil

Background

Suid gammaherpesvirus 3, 4, and 5 (porcine lymphotropic herpesvirus – PLHV-1, -2, and -3) are viruses that infect domestic and feral pigs.

Objectives

This study examined the presence of PLHV DNA in biological samples from free-living wild boars circulating in a Brazilian geographical region with a high density of commercial domestic pigs.

Methods

Lung samples of 50 free-living wild boars were collected by exotic wildlife controller agents between 2017 and 2019 in the state of Paraná, southern Brazil. Lung and spleen fragments were obtained from six fetuses collected by hysterectomy post mortem from a pregnant sow. A polymerase chain reaction (PCR) assay using consensus primers (pan-herpesviruses) was performed to detect PLHV DNA. The samples showing positive results for PLHV DNA were submitted to single-round PCR assays with the specific primers for identifying PLHV-1 (213-S/215-As), PLHV-2 (208-S/212-As), and PLHV-3 (886s/886As). The specificity of the species-specific PCR products was assessed by nucleotide sequencing of the amplicons.

Results

Forty-eight (96%) of the 50 lung samples analyzed were positive for PLHV by PCR using pan-herpesvirus primers. In 33 (68.75%) of the positive samples, at least two PLHV species were identified simultaneously. The DNA of PLHV-1, -2, and -3 was found in free-living wild boars of all ages, but not in the fetuses, even though they were from a sow that tested positive for all three viruses.

Conclusion

These viruses are endemic to the population of feral pigs in the Brazilian region evaluated, as well as in domesticated pigs.

Isolation and characterization of neural stem cells from fetal canine spinal cord

Neurogenesis in adult mammals occurs mainly in the subventricular and subgranular areas of the brain, but there are also reports of its occurrence in the spinal cord. In a study on rats, neural stem cells and neuroprogenitor cells could be obtained through primary spinal cord culture, but there are no studies on these cells in canine species, to date. Dogs represent an appropriate animal model for studies on neurogenesis and neurological disorders. In addition, they are animals of great affective value, and the therapeutic use of neural stem cells can represent a breakthrough in regenerative veterinary medicine. Therefore, this study aimed to determine a protocol for the isolation, culture, and characterization of neural and neuroprogenitor stem cells derived from the spinal cord of canine fetuses. The cells were isolated from spinal cord fragments and cultured in serum-free culture medium supplemented with EGF and FGF-2 growth factors. These cells were observed daily by optical microscopy to analyze their morphological characteristics. From the third day in vitro, it was possible to observe translucent cell groupings, similar to the neurospheres, which approximately ranged from 50 µm to 200 µm at seven days in vitro. Throughout the culture period, the neurospheres developed ribbons in their periphery that migrated and communicated with other neurospheres. RT-PCR revealed that the cells expressed the characteristic genes SOX2, NESTIN, and GFAP. In addition to gene expression, the cells were phenotypically marked in the immunofluorescence assay for the proteins Nestin, GFAP, and β-tubulin III, characterizing them as neurospheres. Our results suggest that the spinal cord may be a source of neural stem cells and neural progenitor cells in canine fetuses. These cells may be an interesting option for neurogenesis and neuroregenerative therapy studies.

Body measurements correlation and x-ray imaging of three Hystrix javanica fetuses in different fetal development stages

Hystrix javanica is endemic species in Indonesia. Study about fetal development of Hystrix javanica are very rare because of sample limitation. This study was carried out to describe the morphometrics and x-ray analysis of three fetuses in different stage to give basic information about fetal development of Hystrix javanica. Three fetus samples fixed in Bouin's solution was used in this study. Observation was carried out to identify the characteristic of three fetus samples. This included the pattern of hair, body measurements, body volume, and body weight. X-ray analysis was carried out to know the ossification process in the fetal development. Statistical analysis was carried out using Microsoft 365® Excel program software. Three fetus samples had different specific hair pattern, that was hairless, smooth hairs, and smooth hairs with dense-non dense pattern. Body volume of 1^st, 2^nd, and 3^rd fetus were 23mL, 90mL, and 170mL, respectively. Body weight of 1^st, 2^nd, and 3^rd fetus were 19.5g, 79.22g, and 153.18g, respectively. Pearson's correlation analysis shown strong relationship between total body length, front body length, back body length, horizontal body diameter, vertical body diameter, head length, and head diameter against body volume and body weight of three fetuses. Significant positive correlation was shown between horizontal body diameter, vertical body diameter, and head diameter against body volume and body length with P value < 0.05. Faint radiopaque images showed in the 2^nd fetus sample and strong radiopaque images showed in the 3^rd fetus sample. Radiopaque images were identified in the teeth, cranium, vertebrae, and extremities bones. In this study we concluded that there was a specific hair pattern in different fetal stage. All body measurements have positive correlation with body volume and body weight and x-ray analysis shown that the ossification of the bone was started to happen while the smooth hair was growth.

Central nervous system development of cats (Felis catus L. 1758)

The morphological similarities of vertebrates' embryonic development are used as a criterion for choosing animal models that can be used in biomedical research. This study describes the embryonic and fetal development of the domestic cat's central nervous system from 15 days after conception until birth. In total, fifty-seven samples of embryos and fetuses were carefully dissected and analyzed microscopically. The closure of the neural tube was observed between 14-15th days of gestation. The differentiation of the primordial cerebral vesicles was observed from the 17th day of gestation. On the 19th day of gestation, the formation of the choroid plexus began, and on the 20th day of gestation, the brain and brainstem were well-identified macroscopically. On the 24th day of gestation, four layers of cells from the cerebral cortex were described, and on the 60th day, six layers of cells were present. The cerebellar cortex had the three classic cortical layers at this stage. The morphological aspects of embryonic and fetal development in cats were very similar to the stages of development of the human nervous system. As such, this study provided relevant information that highlights the domestic cat as an animal model option for preclinical research on infectious and non-infectious neurological diseases in humans.

Stereological analysis of metanephros from domestic cat (Felis catus, Linnaeus 1798) embryos and fetus

Kidney diseases are the most common illness for cats with a prevalence seven times higher than in dogs. Metanephros is the last of three renal systems to be formed during the embryonic period, which then becomes the permanent kidney. The current work aimed to analyse the morphology and to quantify the structures present in the development of metanephros from domestic cat (Felis catus) embryos and foetuses. For this purpose, the evaluation of the biometric parameters of metanephros from cat embryos and foetuses was performed in addition to the quantification of renal corpuscles and volume of cortical and medullary layers by stereological analysis. The evaluated biometric parameters were weight, width, height, thickness and volume. The values of the measured biometric parameters increased throughout the gestational stages. The quantity of renal corpuscles gradually increased following the embryo-foetal development, mainly during the middle of the gestational stage. It was during this phase that morphologically, a complete corticomedullary division was observed. Although the difference in the quantity of renal corpuscles between the middle and the end of the gestational stages was not statistically significant, there was an increase in the volume of the medullary layer and a decrease in the volume of the cortical layer between these two stages. These findings suggest that the metanephros presents a progressive growth with the renal corpuscles following this development until the middle of the gestational stage. Starting from this phase, the differentiation of the corticomedullary layers can be seen with a significant increase in the medullary layer.

Chemotactic behavior of Campylobacter fetus subspecies towards cervical mucus, bovine placenta and selected substances and ion

The chemotaxis of C. fetus subsp. venerealis and C. fetus subsp. fetus was determined in the presence of bovine cervical mucus and bovine placental extract. Some reported substances and ion in those materials, such amino acids, ferrous iron, hormones, sugars and organic acids were also investigated. Bovine cervical mucus, bovine placenta extracts and some substances and ion of these materials namely L–fucose, L– aspartate, L–glutamate, L–serine, ferrous iron, fumarate, pyruvate and succinate were chemoattractants. The chemottraction was significantly larger in higher concentrations of the tested substances and ion and significant differences among tested strains were also observed. Meso-erythritol and hormones bovine placental lactogen, 17β-estradiol, and progesterone did not elicit chemotactical response. In conclusion, this chemotactic behavior may guide the C. fetus navigation in the bovine host's genital tract and be an important cofactor of tissue tropism for this bacterium.

On the Embryonic Development of the Nasal Turbinals and Their Homology in Bats

Multiple corrugated cartilaginous structures are formed within the mammalian nasal capsule, eventually developing into turbinals. Due to its complex and derived morphology, the homologies of the bat nasal turbinals have been highly disputed and uncertain. Tracing prenatal development has been proven to provide a means to resolve homological problems. To elucidate bat turbinate homology, we conducted the most comprehensive study to date on prenatal development of the nasal capsule. Using diffusible iodine-based contrast-enhanced computed tomography (diceCT), we studied in detail the 3D prenatal development of various bat species and non-bat laurasiatherians. We found that the structure previously identified as “maxilloturbinal” is not the true maxilloturbinal and is only part of the ethmoturbinal I pars anterior. Our results also allowed us to trace the evolutionary history of the nasal turbinals in bats. The turbinate structures are overall comparable between laurasiatherians and pteropodids, suggesting that pteropodids retain the ancestral laurasiatherian condition. The absence of the ethmoturbinal I pars posterior in yangochiropterans and rhinolophoids has possibly occurred independently by convergent evolution.

Stereological analysis of the New Zealand rabbits (Oryctolagus cuniculus) placenta

The onset of gestation is characterized by growth, morphological and functional changes of the placenta. We aim to evaluate the placental compartments in New Zealand rabbits by means of stereological methods. The fetal and maternal portion of placenta (12, 14, 18 and 20 gestational days) was randomly sampled for the stereological analysis. Histological sections were scanned to estimate fetal (labyrinth and junctional) and maternal (decidua) compartment volumes. The total volume of the placenta for the ages of 12, 14, 18 and 20 days was, respectively, 320 mm3, 340 mm3, 940 mm3 and 1300 mm3. The volume of the labyrinth was 56 mm3, 119 mm3, 231 mm3 and 481 mm3, respectively. The volume of junctional zone was 75 mm3, 76 cm3, 238 mm3 and 314 mm3, respectively. The volume of decidua was 174 mm3, 143 mm3, 469 mm3 and 504 mm3, respectively. We concluded that the rabbit´s placenta compartments varied according to the gestational period, increasing continuously over the 20 gestational days. However, on the onset of the development of the placenta the decidua presented faster growth, whereas after the 20 days of development, the labyrinth developed more quickly. This study represents an aid to the understanding of placentation in humans.

Central nervous system development in rabbits (Oryctolagus cuniculus L. 1758)

The present study describes the embryonic and fetal development of the central nervous system in rabbits from the seventh day after conception until the end of the full-term fetal period. A total of 19 embryonic and fetal samples were carefully dissected and microscopically analyzed. Neural tube closure was observed between 7.5 and 8 days of gestation. Primordial encephalic vesicle differentiation and spinal canal delimitation were observed on the 12th day of gestation. Histologically, on the 15th day of gestation, the brain, cerebellum, and brain stem were delimited. On the 18th day of gestation, the cervical and lumbar intumescences of the spinal cord were visible. On the 28th day of gestation, four-cell layers could be distinguished in the cerebral cortex, while the cerebellar cortex was still differentiating. Overall, the morphological aspects of the embryonic and fetal developmental phases in rabbits were highly similar to those in humans. Thus, the present study provides relevant information highlighting rabbits as an excellent candidate animal model for preclinical research on human neurological diseases given the high adaptability of rabbits to bioterium conditions and the similarity of morphological events between rabbits and humans.

A descriptive angiographic study of the uterine arteries during pregnancy, the postpartum period and CEH/pyometra in bitches

The aim of this descriptive study was to monitor the changes in uterine arteries during pregnancy, postpartum period and pyometra in bitches using angiography. Fifteen uteri of mixed breed bitches on days 24, 30, 33, 40, 43, 47, 50 and 56 of pregnancy and weeks 1, 2, 3, 4 and 7-8 of postpartum and two CEH/pyometra bitches were examined after ovariohysterectomy. The results showed that with the onset of normal pregnancy and in about 30 ± 1 days of gestation, anastomoses begin to form between the left and right middle uterine arteries, developing during the next days and continuing until 4 weeks postpartum. On 4th week after parturition, when physiologic changes occur and the uterus returns to non-pregnant conditions, these anastomoses begin to degenerate, and they completely disappear approximately on the 7th-8th week after parturition. Similarly, in CEH/pyometra bitches, anastomoses were formed between left and right median uterine arteries. These findings can be considered as a part of the physiological changes of the uterus and its vessels during pregnancy and postpartum periods and could affect the results and interpretation of relevant findings.

Paracervical ganglion in the female pig during prenatal development: Morphology and immunohistochemical characteristics

The present study investigated the development of the paracervical ganglion in 5-, 7- and 10-week-old porcine foetuses using double labelling immunofluorescence method. In 5-week-old foetuses single PGP-positive perikarya were visible only along the mesonephric ducts. They contained DβH or VAChT, and nerve fibres usually were PGP/VAChT-positive. The perikarya were mainly oval. In 7-week-old foetuses, a compact group of PGP-positive neurons (3144±213) was visible on both sides and externally to the uterovaginal canal mesenchyme of paramesonephric ducts. Nerve cell bodies contained only DβH (36.40±1.63%) or VAChT (17.31±1.13%). In the 10-week-old foetuses, the compact group of PGP-positive neurons divided into several large and many small clusters of nerve cells and also became more expanded along the whole uterovaginal canal mesenchyme reaching the initial part of the uterine canal of the paramesonephric duct. The number of neurons located in these neuronal structures increased to 4121±259. Immunohistochemistry revealed that PGP-positive nerve cell bodies contained DβH (40.26±0,73%) and VAChT (30.73±1.34%) and were also immunoreactive for NPY (33.24±1,27%), SOM (23.6±0,44%) or VIP (22.9±1,13%). Other substances studied (GAL, NOS, CGRP, SP) were not determined at this stage of the development. In this study, for the first time, the morphology of PCG formation in the porcine foetus has been described in three stages of development. Dynamic changes in the number of neurons and their sizes were also noted, as well as the changes in immunochistochemical coding of maturing neurons.

Prenatal histomorphological development of the reticulum in fallow deer (Dama dama)

The histomorphological changes occurring in the Dama dama reticulum during prenatal development have been investigated. Twenty-five Dama dama embryos were used, from the first stages of prenatal life until birth. Differentiation of the reticulum was observed at 23% gestation. By 25% gestation the reticular wall comprised three layers: an internal epithelial layer, a middle layer of pluripotential blastemic tissue and an external layer or serosa. Primary reticular crests were visible at 38% gestation. Secondary reticular crests were observed at 61% gestation. Neuroendocrine cells were detected by synaptophysin (SYP) at 35% gestation, in the lamina propria-submucosa, tunica muscularis, and serosa. Epithelial Cytokeratin-18 (CK-18) cells were observed at 35% gestation extended throughout the epithelial layers. The glial cells (vimentin -VIM- and glial fibrillary acidic protein-GFAP-markers) were discerned at 25% and 43% gestation, respectively, in myenteric and submucosal plexuses, lamina propria, muscularis mucosae, tunica muscularis, and perivascular connective tissue. The neuropeptide Y (NPY) and vasoactive intestinal polypeptide (VIP) markers were immunodetected at 75% and 80 gestation, respectively, in the lamina propria-submucosa, muscularis mucosae, tunica muscularis, serosa, and myenteric plexuses. The prenatal development of the fallow deer reticular mucosa evidenced a considerable precocity similar to that previously reported in goat and red deer.

Pluripotent stem cells proliferation is associated with placentation in dogs

Pluripotent stem cells have been studied as source of cells for regenerative medicine and acquire or genetic diseases, as an innovative therapy. Most tissues have stem cells populations, however in few quantities or impossible to be used during adult life, which lead to scientists look for new sources. Thus, this study aimed to analyze the presence of pluripotent cells in the uterus and placenta, following up non-pregnant, pregnant (begin, middle, and final), and postpartum periods in dogs. The uteri were obtained from social castration programs for population control in Pirassununga, Sao Paulo, Brazil. It was collected 20 uteri at different stages. The samples were fixed and processed for immunohistochemical analysis of NANOG, OCT4 and SOX2 expression, knowing as pluripotent stem cells makers. Our results showed positive expression for NANOG, OCT4 and SOX2 in all stages of gestation and nonpregnant uterus; however, we highlight some quantitative different between stages. OCT4 showed more expression in non-pregnant uterus than NANOG and SOX2, and its expression increased in pregnant uterus. In pregnant uterus there was more expression of NANOG than OCT4 and SOX2. Interesting, no difference was found between these markers in the other periods. In conclusion, it was possible to identify pluripotent stem cells in all periods in dog placenta and uterus, however during the early stage of pregnancy we observed more pluripotent stem cells than in all the others periods confirming the high plasticity and regeneration capacity of the uterine tissue.

Formation and characterization of lipid droplets of the bovine corpus luteum

Establishment and maintenance of pregnancy depends on progesterone synthesized by luteal tissue in the ovary. Our objective was to identify the characteristics of lipid droplets (LDs) in ovarian steroidogenic cells. We hypothesized that LDs are a major feature of steroidogenic luteal cells and store cholesteryl esters. Whole bovine tissues, isolated ovarian steroidogenic cells (granulosa, theca, small luteal, and large luteal), and isolated luteal LDs were assessed for LD content, LD-associated proteins and lipid analyses. Bovine luteal tissue contained abundant lipid droplets, LD-associated perilipins 2/3/5, hormone-sensitive lipase, and 1-acylglycerol-3-phosphate O-acyltransferase ABHD5. Luteal tissue was enriched in triglycerides (TGs) compared to other tissues, except for adipose tissue. Luteal cells were distinguishable from follicular cells by the presence of LDs, LD-associated proteins, and increased TGs. Furthermore, LDs from large luteal cells were numerous and small; whereas, LDs from small luteal cells were large and less numerous. Isolated LDs contained nearly all of the TGs and cholesteryl esters present in luteal tissue. Isolated luteal LDs were composed primarily of TG, with lesser amounts of cholesteryl esters, diglyceride and other phospholipids. Bovine luteal LDs are distinct from LDs in other bovine tissues, including follicular steroidogenic cells.

Medications for pregnant women: A balancing act between the interests of the mother and of the fetus

Drug entry into the adult brain is controlled by efflux mechanisms situated in various brain barrier interfaces. The effectiveness of these protective mechanisms in the embryo, fetus and newborn brain is less clear. The longstanding belief that "the" blood-brain barrier is absent or immature in the fetus and newborn has led to many misleading statements with potential clinical implications. Here we review the properties of brain barrier mechanisms in the context of drug entry into the developing brain and discuss the limited number of studies published on the subject. We noticed that most of available literature suffers from some experimental limitations, notably that drug levels in fetal blood and cerebrospinal fluid have not been measured. This means that the relative contribution to the overall brain protection provided by individual barriers such as the placenta (which contains similar efflux mechanisms) and the brain barriers cannot be separately ascertained. Finally, we propose that systematic studies in appropriate animal models of drug entry into the brain at different stages of development would provide a rational basis for use of medications in pregnancy and in newborns, especially prematurely born, where protection usually provided by the placenta is no longer present.

Towards scheduled pre-parturient caesarean sections in bitches

Elective caesarean section (CS) is the safest means of delivering the litter in bitches in specific situations. Timeously performing elective pre-parturient CSs at a fixed time would be convenient and prevent emergency CSs and foetal demise. This review proposes a method of performing elective pre-parturient CSs which is safe for both the bitch and puppies. Brachycephaly, small litters and large litters, preceding litter delivered by CS and trial of labour after a preceding CS are identified as factors increasing the need for CS whereas emergency CS is identified as factor increasing foetal demise. The first day of cytological dioestrus more precisely predicts the day of onset of spontaneous parturition than the first day of the LH surge or the dates during oestrus on which progesterone (P4) first exceeds 6 nM or 16 nM. Foetal biparietal diameter at the time of onset of spontaneous parturition varies too much to accurately predict readiness for CS. During the last few days of gestation, P4 with cut-off concentrations at 15.8, 8.7 and 3.18 nM, but not plasma cortisol concentrations, hold promise as predictors of onset of parturition and when to perform pre-parturient CSs. A protocol associating medetomidine hydrochloride as premedicant with propofol as induction agent and sevoflurane as maintenance is safe for scheduled CS and yields good maternal and puppy survival rates at delivery, 2 hr and 7 days after CSs. Clinicians have to pay attention to the haematocrit of bitches at the time of cervical dilatation which is at the lower end of the normal reference ranges for non-pregnant dogs and to the decline in haematocrit during CS (as a proxy for blood loss) which is approximately 7% for both parturient (open cervix) and pre-parturient (closed cervix) CSs. Pre-parturient CSs can be scheduled and performed 57 days after onset of cytological dioestrus with puppy survival rates of 99%. Collectively, these studies provide a protocol to safely perform elective CSs in a large proportion of the obstetric population at a convenient time of the day but more research is required with larger numbers to establish whether this practice is routinely safe and safe in all breeds.

Transcriptome profiling of buffalo endometrium reveals molecular signature distinct to early pregnancy

Buffalo reproduction struggles with a high incidence of early embryonic mortality. Effective treatment and prevention strategies for this condition are not available due to lack of understanding of molecular pathways in early pregnancy of this species. In the present study, we have attempted to understand these molecular pathways by characterizing the endometrial transcriptomic profiles of pregnant buffalos during early pregnancy. For the transcriptome profiling, buffalo endometrial tissues of 29-36 days of pregnancy and of nonpregnant luteal phase were collected from the local slaughterhouse. We confirmed the status of pregnancy based on the crown vertebral length of the foetus. Total RNA was isolated and sequencing was performed using the Illumina nextseq platform. The raw reads were filtered and mapped to the Bos taurus UMD 3.1 reference genome assembly. An average of 24,597 genes was investigated for differential expression between the two groups. Transcriptome data identified a total of 450 differentially expressed genes (using a cut off value of log₂ fold changes >2 and <-2) in early pregnancy in comparison to the nonpregnant group (P_adj < 0.05). Among these, 270 genes were significantly upregulated and 180 genes were downregulated. The most impacted pathways were related to secretion, transport, ionic homeostasis, mitosis and negative regulation of viral processes. In conclusion, our study characterized a unique set of DEGs, during the early pregnancy of buffalo, which potentially modulate the endometrial environment to establish and maintain a successful pregnancy.

Are scurs in heterozygous polled (Pp) cattle a complex quantitative trait?

Background

Breeding genetically hornless, i.e. polled, cattle provides an animal welfare-friendly and non-invasive alternative to the dehorning of calves. However, the molecular regulation of the development of horns in cattle is still poorly understood. Studying genetic characters such as polledness and scurs, can provide valuable insights into this process. Scurs are hornlike formations that occur occasionally in a wide variety of sizes and forms as an unexpected phenotype when breeding polled cattle.

Methods

We present a unique dataset of 885 Holstein–Friesian cattle with polled parentage. The horn phenotype was carefully examined, and the phenotypic heterogeneity of the trait is described. Using a direct gene test for polledness, the polled genotype of the animals was determined. Subsequently, the existence of a putative scurs locus was investigated using high-density genotype data of a selected subset of 232 animals and two mapping approaches: mixed linear model-based association analyses and combined linkage disequilibrium and linkage analysis.

Results

The results of an exploratory data analysis indicated that the expression of scurs depends on age at phenotyping, sex and polled genotype. Scurs were more prevalent in males than in females. Moreover, homozygous polled animals did not express any pronounced scurs and we found that the Friesian polled allele suppresses the development of scurs more efficiently than the Celtic polled allele. Combined linkage and linkage disequilibrium mapping revealed four genome-wide significant loci that affect the development of scurs, one on BTA5 and three on BTA12. Moreover, suggestive associations were detected on BTA16, 18 and 23. The mixed linear model-based association analysis supports the results of the combined linkage and linkage disequilibrium analysis. None of the mapping approaches provided convincing evidence for a monogenic inheritance of scurs.

Conclusions

Our results contradict the initial and still broadly accepted model for the inheritance of horns and scurs. We hypothesise an oligogenetic model to explain the development of scurs and polledness.

Understanding the effects of the bovine POLLED variants

Horns are paired appendages on the head of bovine species, comprising an inner bony core and outer keratin sheath. The horn bud forms during early fetal development but ossification of the developing horn does not occur until approximately 1 month after birth. Little is known about the genetic pathways that lead to horn growth. Hornless, or polled, animals are found in all domestic bovids. Histological studies of bovine fetuses have shown that the horn bud does not form in polled individuals. There are currently four known genetic variants for polledness in cattle on BTA1. All of the variants are intergenic, but probably affect regulation of nearby genes or long non-coding RNAs. Transcriptomic studies suggest that the expression of two nearby long non-coding RNAs are affected by the Celtic POLLED variant, but further studies are required to confirm these data. Candidate genes located elsewhere in the genome are involved in regulating bone formation and epithelial-to-mesenchymal transition. Expression of one of these candidate genes, RXFP2, appears to be reduced in the fetal horn bud of polled animals carrying the Celtic variant compared with horned individuals. Investigating horn ontogenesis and the genetic pathway by which the POLLED variants prevent horn development has implications for cattle breeding. If the genetic basis of horn bud formation and polledness is better understood, then new targets may be identified for precision genome editing to create polled individuals.

The embryonic development of the bovine stomach revisited

The adult anatomy and physiology of the bovine (Bos taurus) stomach have been investigated extensively. Despite the many studies, however, the early development of the stomach has not yet been fully elucidated. The goal of the present study, therefore, was to review the available literature, to visualize the embryonic and early foetal development of the bovine stomach and to shed light on unresolved issues. The stomachs of fifteen bovine embryos and eleven foetuses from 26 to 80 days of gestation were photographed both in situ and after exenteration and critical point drying. A series of photographs was obtained that yielded a contiguous and comprehensive view of all the developmental changes that occurred until the virtually final configuration of the stomach was attained. In addition, the serosal surface was studied by electron microscopy, thus revealing subtle regional differences in the lining of the peritoneal cavity. Our observations corroborate the contention that all the compartments evolve from the fusiform primordium and that no outgrowth at the level of the oesophagus occurs. The greater curvature as well as the attachment line of the dorsal mesogastrium shift to the left, which is similar to the process in monogastrians. The rumen and reticulum develop from separate protrusions, and further compartmentalization results from constrictions and bulges and not from folding. Between 55 and 60 days of gestation, the entire bovine stomach except for the abomasum eventually relocates to its final position. In summary, previously debated key issues were addressed and integrated with current findings.

Spatiotemporal Mapping of the Contracting Gravid Uterus of the Rabbit Shows Contrary Changes With Increasing Gestation and Dosage With Oxytocin

Spontaneous and oxytocin induced contractile activity was quantified in the bicornuate uteri of pregnant rabbits maintained in situ, using data from two- and uni- dimensional video spatiotemporal maps (VSTM) of linear and area strain rate and compared statistically. Spontaneous contractions occurred over a range of frequencies between 0.1 and 10 cpm, in gravid animals at 18-21 and at 28 days of gestation, and propagated both radially and longitudinally over the uterine wall overlying each fetus. Patches of contractions were randomly distributed over the entire surface of the cornua and were pleomorphic in shape. No spatial coordination was evident between longitudinal and circular muscle layers nor temporal coordination that could indicate the activity of a localized pacemaker. The density and duration of contractions decreased, and their frequency increased with the length of gestation in the non-laboring uterus. Increasing intravenous doses of oxytocin had no effect on the mean frequencies, or the mean durations of contractions in rabbits of 18-21 days gestation, but caused frequencies to decrease and durations to increase in rabbits of 28 days gestation, from greater spatial and temporal clustering of individual contractions. This was accompanied by an increase in the distance of propagation, the mean size of the patches of contraction, the area of the largest patch of contraction and the overall density of patches. Together these results suggest that progressive smooth muscle hypertrophy and displacement with increasing gestation is accompanied by a decrease in smooth muscle connectivity causing an increase in wall compliance and that oxytocin restores connectivity and decreases compliance, promoting volumetric expulsion rather than direct propulsion of the fetus by peristalsis. The latter effects were reversed by the β2 adrenergic receptor agonist salbutamol thus reducing area of contraction, and the duration and distance of propagation.

Canine fetus immune system at late development

The immune system is mainly responsible for protecting the organism against agents that may interfere in its homeostasis. Thus, understand how this system develops and operates is very important, for create new therapies to assist this system in its operation, such as its failure. In domestic dogs, few studies show how actually occurs the development, maturation and functioning of the immune system. Therefore, this study demonstrates the development and possible activation of it on dog fetus from late gestational period by in situ and microscopic analyzes.

Body wall defects and amniotic band syndrome in pig (Sus scrofa domesticus)

The amniotic band syndrome is a congenital condition. It is characterized by the presence of fibrous amniotic bands that may entangle or entrap different foetal parts in utero, resulting in deformation, malformation or disruption. We report on a female piglet presenting amniotic band adherences in the right abdominal flank, several body wall defects (gastroschisis, abdominoschisis with omphalocele), severe scoliosis, anomalous umbilical cord with single umbilical artery, anal atresia, anomalous liver and absent gall bladder, hypoplastic genitalia, ankylosis and arthrogryposis in pelvic limbs, and bilateral patellar agenesia. The ethiopatogenia is discussed, as well as the comparative and embryological implications.

Reliable and Standardized Animal Models to Study the Pathogenesis of Bluetongue and Schmallenberg Viruses in Ruminant Natural Host Species with Special Emphasis on Placental Crossing

Starting in 2006, bluetongue virus serotype 8 (BTV8) was responsible for a major epizootic in Western and Northern Europe. The magnitude and spread of the disease were surprisingly high and the control of BTV improved significantly with the marketing of BTV8 inactivated vaccines in 2008. During late summer of 2011, a first cluster of reduced milk yield, fever, and diarrhoea was reported in the Netherlands. Congenital malformations appeared in March 2012 and Schmallenberg virus (SBV) was identified, becoming one of the very few orthobunyaviruses distributed in Europe. At the start of both epizootics, little was known about the pathogenesis and epidemiology of these viruses in the European context and most assumptions were extrapolated based on other related viruses and/or other regions of the World. Standardized and repeatable models potentially mimicking clinical signs observed in the field are required to study the pathogenesis of these infections, and to clarify their ability to cross the placental barrier. This review presents some of the latest experimental designs for infectious disease challenges with BTV or SBV. Infectious doses, routes of infection, inoculum preparation, and origin are discussed. Particular emphasis is given to the placental crossing associated with these two viruses.

Innervation of internal female genital organs in the pig during prenatal development

This study investigated the innervation of internal genital organs in 5-, 7- and 10-week-old female pig foetuses using single and double-labelling immunofluorescence methods. The structure and topography of the organs was examined using a scanning electron microscope (SEM). The investigations revealed differences in the innervation between the three developmental periods. Immunostaining for protein gene product 9.5 (PGP; general neural marker) disclosed solitary nerve fibres in the external part of the gonadal ridge and just outside of the mesenchyme surrounding mesonephric ducts in 5-week-old foetuses. Double-labelling immunohistochemistry revealed that nerve fibres associated with the ridge expressed dopamine β-hydroxylase (DβH; adrenergic marker) or vesicular acetylcholine transporter (VAChT; cholinergic marker). In 7-week-old foetuses, the PGP-positive nerve terminals were absent from the gonad but some of them ran outside and along, and sometimes penetrated into the mesenchyme surrounding the tubal and uterine segments of the paramesonephric ducts and uterovaginal canal. Few axons penetrated into the mesenchyme. DβH-positive fibres were found in single nerve strands or bundles distributed at the edge of the mesenchyme. VAChT-positive nerve terminals formed delicate bundles located at the edge of the mesenchyme, and the single nerves penetrated into the mesenchyme. DβH was also expressed by neurons which formed cell clusters comprising also DβH- or VAChT-positive nerve fibres. In 10-week-old foetuses, PGP-positive nerve fibres were still absent from the ovary but some were distributed in the mesenchyme associated with the uterovaginal canal and uterine and a tubal segment of the paramesonephric ducts, respectively. DβH- or VAChT-positive nerve fibres were distributed at the periphery of the mesenchyme associated with the uterovaginal canal. Some DβH- and many VAChT-positive nerve fibres were evenly distributed throughout the mesenchyme. The clusters of nerve cells comprised DβH-positive perikarya and DβH- or VAChT-positive nerve fibres. The investigations revealed no DβH/VAChT-positive nerve fibres or neurons as well as no nerve structures stained for calcitonin gene-related peptide and/or substance P (sensory markers) associated with the genital organs in the studied prenatal periods.

Embryonic and fetal development of the collared peccary (Pecari tajacu)

The relative timing of the main fetal development events in species determine the extent of fetal development at birth, which range along a gradient of having altricial and precocial traits. The results from this study allow for description of important fetal developments in collared peccary (Pecari tajacu) using data from 118 embryo/fetuses from 68 pregnant peccaries obtained over a period of 15 years through collaborative methods with local hunters in the Amazon. The chronological order of emergence of external characteristics in relation to the total dorsal length (TDL) was: differentiated genitalia, limbs and eyelid buds (TDL ≥ 4.5 cm), fusioned eyelids and outer ear (TDL ≥ 5.6 cm), dorsal gland (TDL ≥ 7.3 cm), skin (TDL ≥ 9.2 cm), tactile pelage (TDL ≥ 12.9 cm), coverage pelage (TDL ≥ 17.0 cm), opened eyelids (TDL ≥ 21.5 cm) and tooth eruption (TDL ≥ 24.5 cm). The formula of fetal age was ∛W = 0.079 (t - 27.6), with a linear relationship between TDL and gestational age. The relative weight of tubular gastrointestinal organs, lungs, spleen and thymus increased during fetal development. In contrast, the relative weight of kidneys and liver consistently decreased during the fetal development period. Results of this study indicate the collared peccary is a precocial species and that changes during fetal development are very similar to those in other Suiform species.

Metabolites and Lipids Associated with Fetal Swine Anatomy via Desorption Electrospray Ionization - Mass Spectrometry Imaging

Chemical imaging by mass spectrometry (MS) has been largely used to study diseases in animals and humans, especially cancer; however, this technology has been minimally explored to study the complex chemical changes associated with fetal development. In this work, we report the histologically-compatible chemical imaging of small molecules by desorption electrospray ionization (DESI) - MS of a complete swine fetus at 50 days of gestation. Tissue morphology was unperturbed by morphologically-friendly DESI-MS analysis while allowing detection of a wide range of small molecules. We observed organ-dependent localization of lipids, e.g. a large diversity of phosphatidylserine lipids in brain compared to other organs, as well as metabolites such as N-acetyl-aspartic acid in the developing nervous system and N-acetyl-L-glutamine in the heart. Some lipids abundant in the lungs, such as PC(32:0) and PS(40:6), were  similar to surfactant composition reported previously. Sulfatides were highly concentrated in the fetus liver, while hexoses were barely detected at this organ but were abundant in lung and heart. The chemical information on small molecules recorded via DESI-MS imaging coupled with traditional anatomical evaluation is a powerful source of bioanalytical information which reveals the chemical changes associated with embryonic and fetal development that, when disturbed, causes congenital diseases such as spina bifida and cleft palate.

Prenatal Treatment of X-Linked Hypohidrotic Ectodermal Dysplasia using Recombinant Ectodysplasin in a Canine Model

X-linked hypohidrotic ectodermal dysplasia (XLHED) is caused by defects in the EDA gene that inactivate the function of ectodysplasin A1 (EDA1). This leads to abnormal development of eccrine glands, hair follicles, and teeth, and to frequent respiratory infections. Previous studies in the naturally occurring dog model demonstrated partial prevention of the XLHED phenotype by postnatal administration of recombinant EDA1. The results suggested that a single or two temporally spaced injections of EDI200 prenatally might improve the clinical outcome in the dog model. Fetuses received ultrasound-guided EDI200 intra-amniotically at gestational days 32 and 45, or 45 or 55 alone (of a 65-day pregnancy). Growth rates, lacrimation, hair growth, meibomian glands, sweating, dentition, and mucociliary clearance were compared in treated and untreated XLHED-affected dogs, and in heterozygous and wild-type control dogs. Improved phenotypic outcomes were noted in the earlier and more frequently treated animals. All animals treated prenatally showed positive responses compared with untreated dogs with XLHED, most notably in the transfer of moisture through paw pads, suggesting improved onset of sweating ability and restored meibomian gland development. These results exemplify the feasibility of ultrasound-guided intra-amniotic injections for the treatment of developmental disorders, with improved formation of specific EDA1-dependent structures in dogs with XLHED.

Impact of prenatal exposure to bisphenol A on pregnant rats: Fetal bone development and immunohistochemistry implications

BACKGROUND:

Bisphenol A (BPA) is one of the most commonly produced chemicals in the world. BPA is used in products such as food packaging, personal care products, detergents, and plastic bottles. This study was conducted to determine the effect of BPA on fetal bone development.

MATERIAL AND METHODS:

In this study, 16 pregnant female Sprague-Dawley rats were used. The rats were divided into four groups: the control group and 0.5 mg/kg/day, 5 mg/kg/day, and 50 mg/kg/day dose BPA groups. The skeletal system development of fetuses was examined with double skeletal and immunohistochemistry (IHC) staining (tartrate resistant acid phosphatase (TRAP) and the alkaline phosphatase (AP) expressions) methods.

RESULTS:

The highest ossification rates in the humerus, radius, and ulna were detected as 41.05%, 39.25%, and 37.26% in the control group, respectively. The highest ossification rates in the femur, tibia, and fibula were detected as 23.04%, 30.73%, and 32.78% in the control group, respectively. Statistically significant differences were found between control and experimental groups in the TRAP and AP expression of the femur by IHC staining ( p < 0.001).

CONCLUSION:

Exposure to BPA during pregnancy adversely affected ossification and bone growth. A dose-dependent decrease was observed in the rate of ossification.

Establishment of 3-dimensional scaffolds from hemochorial placentas

INTRODUCTION

The extracellular matrix (ECM) is a complex, tissue-specific 3-dimensional network that controls cell processes. ECMs derived from various organs are used to produce biological scaffolds comparable to the native microenvironment. Although placentas are often overlooked, they offer a rich ECM for tissue engineering, especially the hemochorial placentas from rodents and lagomorphs that resemble the ones from humans.

METHODS

Here we established a protocol for decellularization and investigated the ECM in native and decellularized placentas of guinea pigs, rats and rabbits by means of histology, immunohistochemistry, immunofluorescence and scanning electron microscopy.

RESULTS

Effective decellularization were achieved by immersion in 0.25% Sodium Dodecyl Sulfate for 3 days, resulting in an intact ECM, while cells or nuclei were absent. All species had a high diversity of ECM components that varied between areas.

DISCUSSION

Dense fibrous networks in the junctional zone were strongly positive to collagen I, III and IV, fibronectin, and laminin ECM markers. Noticeable response were also found for the decidua, especially along the maternal vessels. The labyrinth had thin fibers strongly positive for fibronectin and laminin, but not much for collagens. In conclusion, we established an effective protocol to obtain biological scaffolds from animal models with hemochorial placentas that possessed promising values for future purposes in Regenerative Medicine.

Morphological and Molecular Analysis of In Vitro Tubular Structures from Bovine Yolk Sac-Derived MSCs

The yolk sac is an extraembryonic membrane, of saccular form, connected to the ventral region of the embryo. It is the main source of nutrition for the embryo during the period when the placenta is not fully formed. The aim of this study was to generate tubular structures using mesenchymal stem cells from the bovine yolk sac (bYS-MSCs) and determine if these structures can be a model for in vitro vasculogenesis. The evaluation of this tissue by histochemistry revealed a strong marking of collagen fibers and PAS technique negativity. In transmission electron microscopy, cytoplasmic organelles with large nuclei were observed. The vessel formation assay on a Matrigel substrate showed that the mesenchymal cells of the yolk sac without growth factors (VEGF) are capable of forming branches, sprouting cells, and tubular structures similar to capillary blood. These tubular structures were xenotransplanted subcutaneously into the mesentery of BALB/c/nude mice; after 45 days, vascularized tissue and extensions of blood vessels around the tubular structures could be observed. Real-time PCR (qPCR) demonstrated an expression of the VEGF gene in different gestational age groups. No difference in distribution or expression was detected among groups. Our results suggest that the spontaneous formation of tubules from the yolk sac can be an experimental model to elucidate initial organogenesis and the possible formation of blood capillaries from in vitro mesenchymal cells and possible route of organoid production.

Ultrastructural study of uterine epithelium in the domestic cat during prenatal development

The study describes the sequence of ultrastructural changes of the endometrial lining epithelium, first in the primordial paramesonephric ducts, then in the differentiating uterine horns, and finally in the mature uterus. The research material comprised female fetuses of the domestic cat, aged 33-63 days post conceptionem (p.c.), and mature females. The ultrastructural observations of the developing epithelium were conducted using transmission electron microscopy (TEM) and light microscopy (LM). The results revealed two basic stages in the development of the uterine mucosal epithelium in the domestic cat: the development of the epithelium of the uterine segment of the paramesonephric ducts, lasting from day 33 to day 42 p.c., and the differentiation of this epithelium into the mucosal epithelium of the uterus, starting after day 42 p.c. and lasting until the end of the prenatal period. The epithelium of the uterine segments of the paramesonephric ducts is pseudostratified with a flat surface, all cells being characterized by the same distribution of desmosomes, ribosomes, rough endoplasmic reticulum (rER) cisternae, and mitochondria in the cytoplasm. The differentiating epithelium of the uterus after day 51 p.c. is pseudostratified with a varied height. In the epithelial cells there are increases of (i) the number and complexity of the junctional complexes, (ii) the number of invaginations of the lateral cell membranes, and (iii) the number of elongated mitochondria, and also there appear distended cisternae of the rER, lipid droplets and clusters of glycogen, which suggest increasing metabolism and secretory activity of the cells during the transformation of the epithelium.

Fibroblast growth factor 18 regulates steroidogenesis in fetal bovine ovarian tissue in vitro

In cattle and other species, the fetal ovary is steroidogenically active before follicular development commences, and there is evidence that estradiol and progesterone inhibit follicle formation and activation. Estradiol levels decline sharply around the time of follicle formation. In the present study, we hypothesized that FGF10 and FGF18, which inhibit estradiol secretion from granulosa cells of antral follicles, also regulate fetal ovarian steroid production. Fetuses were collected at local abattoirs, and age determined by crown-rump length measurements. Real-time polymerase chain reaction assays with RNA extracted from whole ovaries revealed that the abundance of CYP19A1 messenger RNA (mRNA) decreased from 60 to 90 days of gestation, which is consistent with the decline in estradiol secretion previously observed. Immunohistochemistry revealed the presence of FGF18 in ovigerous cords in early gestation and in oocytes later in fetal age (≥150 days). The abundance of FGF18 mRNA increased after Day 90 gestation. Addition of recombinant FGF18 to fetal ovarian pieces inhibited estradiol and progesterone secretion in vitro, whereas FGF10 was without effect. Consistent with these results, FGF18 decreased levels of mRNA for CYP19A1 and CYP11A1 in ovarian pieces in vitro. These data suggest that FGF18 may be an intraovarian factor that regulates steroidogenesis in fetal ovaries.

Physiology and molecular biology of barrier mechanisms in the fetal and neonatal brain

Properties of the local internal environment of the adult brain are tightly controlled providing a stable milieu essential for its normal function. The mechanisms involved in this complex control are structural, molecular and physiological (influx and efflux transporters) frequently referred to as the 'blood-brain barrier'. These mechanisms include regulation of ion levels in brain interstitial fluid essential for normal neuronal function, supply of nutrients, removal of metabolic products, and prevention of entry or elimination of toxic agents. A key feature is cerebrospinal fluid secretion and turnover. This is much less during development, allowing greater accumulation of permeating molecules. The overall effect of these mechanisms is to tightly control the exchange of molecules into and out of the brain. This review presents experimental evidence currently available on the status of these mechanisms in developing brain. It has been frequently stated for over nearly a century that the blood-brain barrier is not present or at least is functionally deficient in the embryo, fetus and newborn. We suggest the alternative hypothesis that the barrier mechanisms in developing brain are likely to be appropriately matched to each stage of its development. The contributions of different barrier mechanisms, such as changes in constituents of cerebrospinal fluid in relation to specific features of brain development, for example neurogenesis, are only beginning to be studied. The evidence on this previously neglected aspect of brain barrier function is outlined. We also suggest future directions this field could follow with special emphasis on potential applications in a clinical setting.