A persistent defect in the blood-brain barrier after ventral funiculus lesion in adult cats: implications for CNS regeneration?
Previous studies have shown that, in adult cats, spinal motoneurons are able to regenerate their axons after lesions in the ventral funiculus of the spinal cord. These axons regrow through a scar tissue composed of glial processes and connective tissue elements before they enter the denervated ventral root. In the present study the integrity of the blood-brain barrier (BBB) in the lesion area was assessed by i.v. injections of horseradish peroxidase (HRP), 3 weeks to 7 months postoperatively. The lesion area in the lumbosacral spinal cord was compared with the intact cervical spinal cord and the area postrema in the light and electron microscope. The results show that the BBB fails after a ventral funiculus lesion. The BBB was not restored during the examined period. The leakage of HRP appears to be the result of a transendothelial vesicular transport. In addition, it was observed that the blood vessels in the lesion area were surrounded by wide and irregular perivascular spaces with broken outer basal laminae. Other studies on traumatic defects in the BBB have indicated that the barrier is reorganized within 4 weeks after the lesion. The possibility that a prolonged defect in the BBB after a ventral spinal cord lesion might be linked with the survival of axonal sprouts is discussed.
Department of Anatomy, Karolinska Institutet, Stockholm, Sweden.
M
M
Risling
H
H
Lindå
S
S
Cullheim
P
P
Franson
D000818:Animals; D001812:Blood-Brain Barrier; D002415:Cats; D006735:Horseradish Peroxidase; D009416:Nerve Regeneration; D013116:Spinal Cord / Q000098:blood supply* / Q000473:pathology
D006735:Horseradish Peroxidase