Hemoglobin-Induced Oxidative Stress Contributes to Matrix Metalloproteinase Activation and Blood–Brain Barrier Dysfunction in vivo

M Katsu, K Niizuma, H Yoshioka… - Journal of Cerebral …, 2010 - journals.sagepub.com
M Katsu, K Niizuma, H Yoshioka, N Okami, H Sakata, PH Chan
Journal of Cerebral Blood Flow & Metabolism, 2010journals.sagepub.com
Hemoglobin (Hb) released from extravasated erythrocytes is implicated in brain edema after
intracerebral hemorrhage (ICH). Hemoglobin is a major component of blood and a potent
mediator of oxidative stress after ICH. Oxidative stress and matrix metalloproteinases
(MMPs) are associated with blood–brain barrier (BBB) dysfunction. This study was designed
to elucidate whether Hb-induced oxidative stress contributes to MMP-9 activation and BBB
dysfunction in vivo. An intracerebral injection of Hb into rat striata induced increased …
Hemoglobin (Hb) released from extravasated erythrocytes is implicated in brain edema after intracerebral hemorrhage (ICH). Hemoglobin is a major component of blood and a potent mediator of oxidative stress after ICH. Oxidative stress and matrix metalloproteinases (MMPs) are associated with blood–brain barrier (BBB) dysfunction. This study was designed to elucidate whether Hb-induced oxidative stress contributes to MMP-9 activation and BBB dysfunction in vivo. An intracerebral injection of Hb into rat striata induced increased hydroethidine (HEt) signals in parallel with MMP-9 levels. In situ gelatinolytic activity colocalized with oxidized HEt signals in vessel walls, accompanied by immunoglobulin G leakage and a decrease in immunoactivity of endothelial barrier antigen, a marker of endothelial integrity. Administration of a nonselective MMP inhibitor prevented MMP-9 levels and albumin leakage in injured striata. Moreover, reduction in oxidative stress by copper/zinc-superoxide dismutase (SOD1) overexpression reduced oxidative stress, MMP-9 levels, albumin leakage, and subsequent apoptosis compared with wild-type littermates. We speculate that Hb-induced oxidative stress may contribute to early BBB dysfunction and subsequent apoptosis, partly through MMP activation, and that SOD1 overexpression may reduce Hb-induced oxidative stress, BBB dysfunction, and apoptotic cell death.
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