Morphological study of surgically induced open neural tube defects in chick embryos--postoperative 24 hours

Abstract

For the experimental study of neural tube defect (NTD), a surgical model has advantages over other models in a few aspects. It causes less functional derangement of cells and the NTDs can be made selectively by surgery. The authors planned to use the surgical model for the experimental study of NTD. As the first step for the studies, the chronological changes of morphology during the early postoperative period were investigated using postincubation 3-day chick embryos. The objectives of this study are (1) the morphological evaluation of the surgical model as a method for studies of open NTD, and (2) the observation of morphological changes for the first 24 hours after surgery which include 'overgrowth' appearance and the continuity between the surface ectoderm and the neuroectoderm. The morphological changes were observed by light microscope and scanning electron microscope. Immediately after surgery, typical open NTDs were observed. Morphologically they were very similar to the appearance of spontaneous (non-surgical) open NTDs. The opened neural tubes were everted progressively and they looked rather flat at 24 hours after surgery. Cellular hyperplasia ('overgrowth' appearance) was noted within 24 hours after surgery and became more prominent during the 24 hours. There was increasing continuity between the surface ectoderm and the neural tissue until 24 hours after surgery when the continuity looked almost complete. In conclusion, surgically induced NTDs are morphologically very similar to spontaneous NTDs.(ABSTRACT TRUNCATED AT 250 WORDS)

Feedback between tissue packing and neurogenesis in the zebrafish neural tube

“…We speculate that the increased growth is a result of the reduction in physical constraints acting on the neural tube. This has been directly observed in surgical models of NTDs, in which surgically removing the skin overlying the spinal cord results in increased proliferation in chick embryos (You et al, 1994). However, more experiments are required to determine to what extent such a space-filling mechanism is actually operating in the zebrafish neural tube, and its significance during unperturbed development.…”

Effects of Levetiracetam on neural tube development and closure of the chick embryos in ovo

“…Due to the fact that simple observational period for the young embryos, shorter developmental period, and presence of easy surgical manipulation, and comparatively inexpensive and effortless availability characteristics of the eggs, chick embryo model has been widely used for such investigations about effects of drugs or various substances on the embryo [21].…”

Temporal and spatial patterns of glial differentiation in the surgically induced spinal open neural tube defect of chick embryos: astrocytic, radial glial and microglial differentiations

“…In the surgically induced ONTD model, the neural tube was opened through the roof plate with minimal injury to the mantle layer of the neural tube so that each neuroepithelial cell was probably viable even though the configurations were greatly changed. The major changes seemed to be a wide separation of the dorsal tip of the neural tube, making it flat, and the spatial rearrangement of the neuroepithelial cells [23]. In addition, the composition of the amniotic fluid was not yet very different from that of either extracellular fluid or cerebrospinal fluid.…”