[Breakdown of the blood-brain barrier and clearance of extravasated proteins after experimental brain injury].
It is well recognized that extravasation of circulating proteins is contributed to the formation of vasogenic brain edema after traumatic brain injury. However, clearance of the extravasated proteins from brain tissue remains unclear. In the present study we therefore identified the clearance procedure by evaluating extravascular localization of endogenous serum albumin and exogenous protein tracer, horseradish peroxidase (HRP), after experimental brain injury in rats. Adult male Wistar rats were subjected to a lateral fluid percussive injury. In study 1, HRP was given intravenously 10 minutes before sacrifice. Animals were sacrificed at 1, 2, 24, 72 hours and 7 days after injury in order to determine re-establishment of the blood-brain barrier. In study 2 extravascular accumulation of serum albumin and HRP given before impact was examined at 1, 6, 24, 72 hours and 7 days after injury to evaluate the clearance of these extravasated proteins. Localization of each protein was assessed in injured brain sections at the microscopic level. In study 1, breakdown of the blood-brain barrier was noted in various regions of the injured brain at 1 hour. This barrier disruption was restored in almost regions by 2 hours. Impact site, however, remained permeable upto 72 hours. In study 2, the distribution of extravasated proteins was similar between albumin and HRP at 1 hour post-injury. Pronounced extravasation of both proteins occurred in discrete regions through the injured brain. After 6 hours post-injury a differential accumulation was noted between albumin and HRP. The diffuse extracellular accumulation of albumin was most widespread at 24 hours and less intense at 72 hours.(ABSTRACT TRUNCATED AT 250 WORDS)
Fukuda
K
K
Department of Neurosurgery, Chiba University School of Medicine, Japan.
Tanno
H
H
Okimura
Y
Y
Nakamura
M
M
Yamaura
A
A
D000818:Animals; D001812:Blood-Brain Barrier; D001921:Brain / Q000378:metabolism; D001930:Brain Injuries / Q000378:metabolism*; D005110:Extracellular Space / Q000378:metabolism; D006735:Horseradish Peroxidase / Q000493:pharmacokinetics; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012709:Serum Albumin / Q000378:metabolism*
D012709:Serum Albumin; D006735:Horseradish Peroxidase