Vagal neural crest contribution to the chick embryo cloaca (original) (raw)
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The timing of enteric neural crest cell colonisation of the chick embryo cloaca
Pediatric Surgery International, 2004
Neural crest cell (NCC) migration and formation of the enteric nervous system (ENS) is an essential process in the development of the normal human gut. Abnormalities of the ENS lead to a number of neurochristopathies. In avian embryos, the cloaca acts as a common chamber into which gastrointestinal, urinary and genital tracts emerge. Previous studies have elucidated the specific timeframes at which NCCs reach the various regions of the developing chick gut but, to date, none have looked at NCC colonisation of the cloaca. The aim of our study was to investigate the exact timing of the appearance of NCCs in the cloaca of chick embryos. Chicken embryos were harvested on embryonic days (E) 8-12. Whole embryos were fixed, embedded in paraffin and sectioned. Fluorescent immunohistochemistry, using an anti-HNK-1/N-CAM monoclonal antibody, was performed and images were obtained by confocal microscopy. There was no evidence of NCCs in the cloaca of embryos from E8 to E11. Intense immunoreactivity to HNK-1 first appeared in the cloaca of E12 embryos, demonstrating a profuse circumferential colonisation by NCCs at this time. Our study is the first to show the exact timing of enteric NCC colonisation of the chick embryo cloaca. Further studies, involving quail-chick chimeras, are required to establish the true origin of cloacal NCCs and to establish the relationship between NCCs and persistent cloaca.
Cellular development of the enteric nervous system in the chick embryo
1997
The chemical and structural development of enteric plexuses was studied in the chick from embryonic day 4 to hatching. The enteric ganglia consist of neural crest-derived neuronal and glial cells, which can be distinguished morphologically and immunohistochemically in late developmental stages. At what stage different cell lineages originate from uncommitted precursors remains unknown. While the primordial neurons and glial cells could not be distinguished ultrastnicturally from each other until E16, by means of polyclonal antibodies against GFAP and tubulin, distinct populations of neuronal and glial cells were identified from E5 in the duodenal myenteric ganglia. The enteric ganglia display a compact structure with exclusion of blood vessels and collagen, from the earliest stages investigated. A basement membrane, of unknown origin, is recognized ultrastnicturally around ganglia and connecting strands from E12. The distribution of laminin, a basement membrane component, was examin...
Immunophenotypic characterization of enteric neural crest cells in the developing avian colorectum
Developmental Dynamics, 2012
Background-The enteric nervous system (ENS) develops from neural crest-derived cells that migrate along the intestine to form two plexuses of neurons and glia. While the major features of ENS development are conserved across species, minor differences exist, especially in the colorectum. Given the embryologic and disease-related importance of the distal ENS, the aim of this study was to characterize the migration and differentiation of enteric neural crest cells (ENCCs) in the colorectum of avian embryos. Results-Using normal chick embryos and vagal neural tube transplants from GFP-transgenic chick embryos, we find ENCCs entering the colon at embryonic day (E) 6.5, with colonization complete by E8. Undifferentiated ENCCs at the wavefront express HNK-1, N-cadherin, Sox10, p75, and L1CAM. By E7, differentiation begins in the proximal colon, with L1CAM and Sox10 becoming restricted to neuronal and glial lineages, respectively. By E8, multiple markers of differentiation are expressed along the entire colorectum. Conclusions-Our results establish the pattern of ENCC migration and differentiation in the chick colorectum, demonstrate the conservation of marker expression across species, highlight a range of markers, including neuronal cell adhesion molecules, which label cells at the wavefront, and provide a framework for future studies in avian ENS development.
Differences in nitrergic innervation of the developing chick cloaca and colorectum
Pediatric Surgery International, 2006
The intrinsic innervation of the developing gut has long been a subject of investigation, but little is known regarding that of the embryonic cloaca. The cloaca, like the rest of the gastrointestinal tract, is intrinsically innervated by the enteric nervous system. Nitrergic neurons and fibres make up a large part of this system, thus, their distribution provides us with a useful insight into its development. Cloacal and colorectal tissue specimens were removed from chick embryos at embryonic days 11 (E11), E15 and E19. NADPHdiaphorase (NADPH-d) histochemistry was carried out using whole mount tissue preparations. Ganglia density, the number of NADPH-d-positive cells per ganglia in the myenteric plexus and cell size were calculated and statistical analysis was performed to compare both regions of the gut (P<0.001). There were significant differences in the ganglia density in the cloaca compared to the colorectum at E11 (P<0.05) and E15 (P<0.01), with the colorectum having a much denser network. In both the cloaca and the colorectum, ganglia density significantly decreased with age (P<0.001), while significant differences were observed in the number of NADPH-d-positive cells per ganglia in both regions through development. Total cell size was similar in both the cloaca and colorectum at each stage and increased in both regions through development, predominantly due to an increase in the cytoplasm. Results reveal striking differences in innervation between the chick embryo cloaca and colorectum. The sparse network of innervation evident within the cloaca in contrast to the dense network within the colorectum emphasizes the individuality of both regions. These results highlight the need for a further in-depth analysis of the enteric nervous system's development within the embryonic cloaca.
Developmental Dynamics, 1993
The enteric nervous system (ENS) in avian embryos is formed by cells that migrate to the bowel from vagal and sacral regions of the neural crest. Experiments were carried out to evaluate the developmental potential of crest-derived cells at the time they colonize the gut. Backtransplantation of E4 quail foregut (or control aneuronal hindgut) was used to determine whether crest-derived cells that have previously colonized the bowel are capable of following defined neural crest migration pathways in host embryos. Vagal and sacral, but not truncal, backgrafts provided donor cells for the host's bowel. These cells were immunostained by the neural crest marker, NC-1, restricted to the ENS, and appeared only when foregut was backgrafted; therefore, they were crest-derived. In order for cells to migrate to the host's bowel, backgrafts evidently had to be located in the vicinity of the neuraxis at the time crest-derived cells exited from them. When vagal grafts moved away from the neuraxis, crest-derived donor cells colonized cephalic ganglia and the vagus nerves near the grafts; however, such cells did not migrate down the vagi to the host's gut. Sacral backgrafts provided crestderived cells for the bowel only if the donor gut was transplanted prior to the formation of somite 28, at the level of the disappearing primitive streak. Cells from vagal backgrafts were capable of reaching the host's cloaca, but backgrafts placed at a sacral level colonized only the postumbilical bowel. In addition, donor cells proliferated extensively within the host's gut. Whenever the host's gut was colonized, donor crest-derived cells were also found in non-enteric targets including nerves, cephalic (vagal backgrafts), or sympathetic (sacral backgrafts) ganglia; however, donor cells did not form ectomesenchyme or melanocytes. These data suggest that (i) crest-derived cells that have colonized the bowel remain capable of re-migrating and following defined neural crest migration pathways in host embryos; (ii) remigrating cells must enter these pathways at their start; (iii) the gut stimulates the proliferation of enteric crest-derived cells; (iv) vagal crest-derived cells can follow sacral pathways to reach enteric, Remak's, or sympathetic ganglia; and (v) the migration of crest-derived cells within the gut is determined more by the route they follow to reach the bowel than by their level of origin in the neural crest.
An immunohistochemical study of enteric nervous system in the chick model
The Iranian Journal of Veterinary Science and Technology, 2013
The chick model is a useful research tool to investigate the development of the enteric nervous system (ENS). Recognition of appropriate markers for detection of chick enteric ganglia will allow better utilization of this model to study abnormalities of the ENS. This study aimed to validate a set of antibodies for avian ENS studies on wax sections. The specimens were taken from jejunum and colorectum of early post-hatching chicks, fixed in 4% buffered formaldehyde and stained using haematoxylin and eosin (H&E). Glial fibrillary acidic protein (GFAP), neuron specific enolase (NSE), synaptophysin and S-100 immunohistochemical biomarkers were employed on paraffin-embedded blocks to identify enteric ganglia. The immuno-reactivity scoring was recorded using a semi-quantitative fourtiered system (0, 1+, 2+, and 3+). In jejunum specimens, the immune-reactivity of GFAP was significantly higher than both synaptophysin (p=0.001) and S-100 (p=0.001). There was also a significant difference (p=...