Ultrastructural features of immaturity in blood vessels of neonatal rat spinal cord.
Ultrastructural study was carried out on the lumbo-sacral segment of the spinal cord in 1, 3, 6, 9, 12, 15, 18, 21 and 25-day-old rats. Unusual features of blood vessels in postnatal life of rats were observed: capillaries with abundant endothelial cells, numerous invaginations and narrow lumen. In addition, microvilli of diverse size and number on the luminal surface of capillaries as well as larger vessels were present. They were more numerous in younger animals. An intriguing finding, not observed in older animals, was the appearance of abluminal protrusions projecting into surrounding tissue. Closed endothelial junctions were noted in all the investigated vessels. The above mentioned ultrastructural features indicate an immature character of blood vessels. The presence of this kind of vessels during the postnatal period may be connected with vascularisation of spinal cord due to the myelination process.
Rafałowska
J
J
Medical Research Centre, Polish Academy of Sciences, Warszawa.
Fidziańska
A
A
Jamrozik
Z
Z
D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D001808:Blood Vessels / Q000254:growth & development / Q000648:ultrastructure*; D002196:Capillaries / Q000648:ultrastructure; D004730:Endothelium, Vascular / Q000648:ultrastructure; D007365:Intercellular Junctions / Q000648:ultrastructure; D008159:Lumbar Vertebrae; D008854:Microscopy, Electron; D008871:Microvilli / Q000648:ultrastructure; D018919:Neovascularization, Physiologic / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D012447:Sacrum; D013116:Spinal Cord / Q000098:blood supply* / Q000254:growth & development