Scanning-electron-microscopic studies on the pathogenesis of exencephaly and cranioschisis induced in the rat after neural tube closure.
Following a single-dose (15 mg/kg) administration of cyclophosphamide on day 12 of gestation to Wistar rats, fetuses were collected at various intervals of time and studied under the scanning electron microscope. Comparisons were made with age-matched controls. Disorganization of the neuro-epithelium (NE) was characterized by expansion of the intercellular space (ICS), appearance of abundant cellular debris, extravascular red blood cells and formation of haemorrhagic cysts in the subependymal zone. Proliferation of the choroid plexus and its surface modifications parallelled the changes in the NE. The ventricular system dilated progressively. Supra-ependymal elements appeared earlier and in greater abundance in the experimental than in the control embryos. The mesenchymal cells of the cyclophosphamide-treated embryos were scanty, poorly organized, had less numerous cytoplasmic processes than the corresponding controls and failed to develop into the primordium of the skull vault. Degenerative changes in the NE, ventricular dilatation and the absence of a supporting skull vault primordium appeared to underlie the reopening of the closed neural tube.
Padmanabhan
R
R
Department of Anatomy, Faculty of Medicine, Kuwait University.
D000818:Animals; D001921:Brain; D002490:Central Nervous System / Q000196:embryology*; D003520:Cyclophosphamide / Q000494:pharmacology; D005314:Embryonic and Fetal Development / Q000187:drug effects; D005260:Female; D005865:Gestational Age; D008855:Microscopy, Electron, Scanning; D011247:Pregnancy; D051381:Rats; D011919:Rats, Inbred Strains; D012886:Skull / Q000002:abnormalities*
D003520:Cyclophosphamide