Background and Purpose-Cell death, especially apoptosis, occurred in brain tissues after subarachnoid hemorrhage (SAH). We examined the relationships between apoptosis and the disruption of blood-brain barrier (BBB), brain edema, and mortality in an established endovascular perforation model in male Sprague-Dawley rats. Methods-A pan-caspase inhibitor (z-VAD-FMK) was administered intraperitoneally at 1 hour before and 6 hours after SAH. Expression of caspase-3 and positive TUNEL was examined as markers for apoptosis. Results-Apoptosis occurred mostly in cerebral endothelial cells, partially in neurons in the hippocampus, and to a lesser degree in the cerebral cortex. Accordingly, increased BBB permeability and brain water content were observed, accompanied by neurological deficit and a high mortality at 24 hours after SAH. z-VAD-FMK suppressed TUNEL and caspase-3 staining in endothelial cells, decreased caspase-3 activation, reduced BBB permeability, relieved vasospasm, abolished brain edema, and improved neurological outcome. Conclusions-The major effect of z-VAD-FMK on early brain injury after SAH was probably neurovascular protection of cerebral endothelial cells, which results in less damage on BBB.

Apoptosis in the endothelium of major cerebral arteries may play a role in the initiation and maintenance of cerebral vasospasm after subarachnoid hemorrhage (SAH). We tested the therapeutic effect of caspase inhibitors on endothelial apoptosis and on cerebral vasospasm in an established dog double-hemorrhage model. Thirty-one mongrel dogs were divided into five groups: control; SAH; SAH treated with vehicle [DMSO]; SAH treated with Ac-DEVD-CHO [a specific caspase-3 inhibitor]; and SAH treated with Z-VAD-FMK [a broad caspase inhibitor]. The inhibitors (100 microM) were injected into the cisterna magna daily from Day 0 through Day 3. Angiography was performed on Day 0 and Day 7. Histology, TUNEL staining, and immunohistochemistry were conducted on basilar arteries collected on Day 7 after SAH. Positive staining of TUNEL, poly(ADP)-ribose polymerase (PARP), caspase-3, and caspase-8 was observed in the endothelial cells of the spastic arteries. Double fluorescence labeling demonstrated co-localization of TUNEL with caspase-3 and TNFalpha receptor-1 (TNFR1). Ac-DEVD-CHO and Z-VAD-FMK prevented endothelial apoptosis and reduced angiographic vasospasm. The mechanism of apoptosis in endothelial cells involves TNFR1 and the caspase-8 and caspase-3 pathways. Caspase inhibitors may have potential in the treatment of cerebral vasospasm.

Summary:Matrix metalloproteinase-9 (MMP-9) participates in the disregulation of blood-brain barrier during hemorrhagic transformation, and exacerbates brain injury after cerebral ischemia. However, the consequences of long-term inhibition or deficiency of MMP-9 activity (which might affect normal collagen or matrix homeostasis) remains to be determined. The authors investigated how MMP-9 gene deficiency enhances hemorrhage and increases mortality and neurologic deficits in a collagenase-induced intracerebral hemorrhage (ICH) model in MMP-9-knockout mice. MMP-9-knockout and corresponding wild-type mice at 20 to 35 weeks were used to model an aged population (because advanced age is a significant risk factor in human ICH). Collagenase VII-S (0.5 L, 0.075 U) was injected into the right basal ganglia in mice and mortality, neurologic deficits, brain edema, and hemorrhage size measured. In addition, MMP-9 activity, brain collagen content, blood coagulation, cerebral arterial structure, and expressions of several MMPs were examined. Increased hemorrhage and brain edema that correlated with higher mortality and neurologic deficits were found in MMP-9-knockout mice. No apparent structural changes were observed in cerebral arteries, even though brain collagen content was reduced in MMP-9-knockout mice. MMP-9-knockout mice did exhibit an enhanced expression of MMP-2 and MMP-3 in response to ICH. The results indicate that a deficiency of MMP-9 gene in mutant mice increases collagenase-induced hemorrhage and the resulting brain injury. The intriguing relationship between MMP-9 deficiency and collagenase-induced ICH may reflect the reduction in collagen content and an enhanced expression of MMP-2 and MMP-3. Key Words: MMP-9-Intracerebral hemorrhage-Collagenase-Edema-Blood-brain barrier-Coagulation.Spontaneous intracerebral hemorrhage (ICH) is one of the most serious stroke events, and results in high mortality and morbidity in patients (Bernardini and DeShaies, 2001;Panagos et al., 2002;Woo and Broderick, 2002). Mortality in ICH is often as high as 50% within the first month after ICH, with 50% of these deaths occurring within 48 hours (Broderick, 1993). The mechanisms of ICH-induced early brain injury (e.g. brain edema) have been investigated (Altumbabic et al., 1998;Del Bigio et al., 1999;Xi et al., 2002); however, the complete etiology of early brain injury in ICH is incompletely understood.Matrix metalloproteinases (MMPs) are involved in the pathogenesis of cerebral vascular disorders, particularly the formation and rupture of aneurysms. For example, pro-MMP-2 has been implicated as a significant component within arterial walls of intracerebral aneurysms that leads to subarachnoid hemorrhage (Todor et al., 1998). Other studies also support elevated MMP (elastase and collagenase) activity in ruptured vessels in subarachnoid hemorrhage but not in unruptured aneurysms (Gaetani et al., 1999). MMPs are also involved in the hemorrhagic transformation after cerebral ischemia, especially after thrombolysis (Hosomi et al., 2001;M...

Summary: The hypothesis was tested that hyperbaric oxygen therapy (HBO) reduced brain infarction by preventing apoptotic death in ischemic cortex in a rat model of focal cerebral ischemia. Male Sprague-Dawley rats were subjected to middle cerebral artery occlusion/reperfusion (MCAO/R) and subsequently were exposed to HBO (2.5 atmospheres absolute) for 2 h, at 6 h after reperfusion. Rats were killed and brain samples were collected at 24, 48, 72 h, and 7 days after reperfusion. Neurologic deficits, infarction area, and apoptotic changes were evaluated by clinical scores, 2,3,7-triphenyltetrazolium chloride staining, caspase-3 expression, DNA fragmentation assay, and terminal deoxynucleotidyl transferase-mediated 2Ј-deoxyuridine 5Ј-triphosphate-biotin nick end labeling (TUNEL)-hematoxylin and eosin (H&E) costaining. In MCAO/R without HBO treatment animals, DNA fragmentation was observed in injured cortex at 24, 48, and 72 h but not in samples at 7 days after reperfusion. Double labeling of brain slides with NeuN and caspase-3 demonstrated neurons in the injured cortex labeled with caspase-3. TUNEL+H&E costaining revealed morphologic apoptotic changes at 24, 48, and 72 h after reperfusion. Hyperbaric oxygen therapy abolished DNA fragmentation and reduced the number of TUNEL-positive cells. Hyperbaric oxygen therapy reduced infarct area and improved neurologic scores at 7 days after reperfusion. One of the molecular mechanisms of HBO-induced brain protection is to prevent apoptosis, and this effect of HBO might preserve more brain tissues and promote neurologic functional recovery. Key Words: Cerebral ischemia-HBO-Apoptosis-Infarction.Cell death, either necrosis or apoptosis, occurred in the brain tissues during the first few days after cerebral ischemia (Johnson et al., 1995;Rink et al., 1995). Necrotic cell death is characterized by cellular swelling, nuclear pyknosis with karyorrhexis, and cytoplasmic eosinophilia (Searle et al., 1982;Dure et al., 1995). Apoptosis is characterized by morphologic and biochemical features, including cell shrinkage, formation of apoptotic bodies, and extensive internucleosomal fragmentation (Johnson Jr et al., 1995, 1996. Cerebral hypoxia/ischemia produces a cascade of interconnected pathologic processes, including changes in intracellular Ca 2+ , excitatory amino acid, oxidative stress, and inflammatory response, and leads to apoptosis in the ischemic penumbra (Okamoto et al., 1993;Johnson Jr et al., 1995;Rink et al., 1995;Leker et al., 1999). Prevention of apoptosis becomes a therapeutic strategy to preserve brain tissues and promote functional recovery (Graham and Chen, 2001).Hyperbaric oxygen therapy (HBO) is a potent mean to increase the amount of oxygen dissolved in blood plasma and thereby delivered to the ischemic brain. However, HBO is not currently used in acute stroke management, partially due to the insufficient information of its molecular mechanisms (Kawamura et al., 1990;Anderson et al., 1991;Mink and Dutka, 1995;Nighoghossian and Trouillas, 1997;Chuba et al., 1997;Ro...

The major risk factors for intracerebral hemorrhage (ICH) are hypertension and aging. A fundamental mechanism for hypertension-and aging-induced vascular injury is oxidative stress. We hypothesize that oxidative stress has a crucial role in ICH. To test our hypothesis, we used bacterial collagenase to produce ICH in wild-type C57BL/6 and gp91 phox knockout (gp91 phox KO) mice (deficient in gp91 phox subunit of the superoxide-producing enzyme NADPH oxidase). All animals were studied at 20-35 weeks of age, resembling an older patient population. We found that collagenase produced less bleeding in gp91 phox KO mice than wild-type mice. Total oxidative product was lower in gp91 phox KO mice than in wildtype mice, both under basal conditions and after ICH. Consistent with the ICH volume, brain edema formation, neurological deficit and a high mortality rate was noted in wild-type but not in gp91 phox KO mice. This ICH-induced brain injury in wild-type mice is associated with enhanced expression of the gp91 phox subunit of NADPH oxidase. In conclusion, the oxidative stress resulting from activation of NADPH oxidase contributes to ICH induced by collagenase and promotes brain injury.