Hyperbaric oxygen reduces basal lamina degradation after transient focal cerebral ischemia in rats.
Hyperbaric oxygen (HBO) has been shown to preserve the integrity of the blood-brain barrier after cerebral ischemia. However, the underlying molecular mechanisms are currently unknown. We examined the effect of HBO on postischemic expression of the basal laminar component laminin-5 and on plasma matrix metalloproteinase-9 (MMP) levels. Wistar rats underwent occlusion of the middle cerebral artery (MCAO) for 2 h. With a delay of 45 min after filament introduction, animals breathed either 100% O2 at 1.0 atmosphere absolute (ata; NBO) or at 3.0 ata (HBO) for 1 h in an HBO chamber. Laminin-5 expression was quantified on immunohistochemical sections after 24 h of reperfusion. Plasma MMP-9 levels were measured using gelatin zymography before MCAO as well as 0, 6 and 24 h after reperfusion. Immunohistochemistry 24 h after ischemia revealed a decrease of vascular laminin-5 staining in the ischemic striatum to 43 +/- 26% of the contralateral hemisphere in the NBO group which was significantly attenuated to 73 +/- 31% in the HBO group. Densitometric analysis of zymography bands yielded significantly larger plasma MMP-9 levels in the NBO group compared to the HBO group 24 h after ischemia. In conclusion, HBO therapy attenuates ischemic degradation of cerebral microvascular laminin-5 and blocks postischemic plasma MMP-9 upregulation.
Department of Neurology, Ruprecht-Karls-University Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany. roland_veltkamp@med.uni-heidelberg.de
Roland
R
Veltkamp
Katja
K
Bieber
Simone
S
Wagner
Christopher
C
Beynon
Dirk A
DA
Siebing
Claudia
C
Veltkamp
Markus
M
Schwaninger
Hugo H
HH
Marti
D000818:Animals; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D004195:Disease Models, Animal; D007839:Functional Laterality; D006931:Hyperbaric Oxygenation; D007150:Immunohistochemistry / Q000379:methods; D002546:Ischemic Attack, Transient / Q000378:metabolism* / Q000473:pathology / Q000628:therapy*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000097:blood*; D051381:Rats; D017208:Rats, Wistar; D015424:Reperfusion / Q000379:methods; D013997:Time Factors; D000097794:Kalinin
D015815:Cell Adhesion Molecules; D020780:Matrix Metalloproteinase 9; D000097794:Kalinin