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Diabetes mellitus substantially increases the risk of stroke and enhances brain's vulnerability to ischemia insult. Electroacupuncture (EA) pretreatment was proved to induce cerebral ischemic tolerance in normal stroke models. Whether EA could attenuate cerebral ischemia injury in diabetic mice and the possible underlying mechanism are still unrevealed. Male C57BL/6 mice were subjected to streptozotocin (STZ) for diabetic models. After inducing focal cerebral ischemia model, the levels of plasma and cerebral adiponectin (APN) were measured as well as the expression of cerebral adiponectin receptor 1 (AdipoR1) and 2 (AdipoR2). The neurobehavioral score, infarction volume, and cellular apoptosis were evaluated with or without AdipoR1 short interfering RNA (siRNA). The role of phosphorylation of glycogen synthesis kinase 3 beta (GSK-3β) at Ser-9 in the EA pretreatment was also assessed. EA pretreatment increased both plasma and cerebral APN levels and enhanced neuronal AdipoR1 in diabetic mice. In addition, EA reduced infarct size, improved neurological outcomes, and inhibited cell apoptosis after reperfusion. These beneficial effects were reversed by AdipoR1 knockdown. Furthermore, EA increased GSK-3β phosphorylation (p-GSK-3β) in the ipsilateral penumbra. Augmented p-GSK-3β induced neuroprotective effects similar to those of EA pretreatment. In contrast, dampened p-GSK-3β could reverse the neuroprotective effects of EA. In addition, the increase in p-GSK-3β by EA was abolished by AdipoR1 knockdown. We conclude that EA pretreatment increases the production of APN, which induce protective effects against cerebral ischemia-reperfusion injury through neuronal AdipoR1-mediated phosphorylation of GSK-3β in diabetic mice.

Background It is well known that ischemic postconditioning reduces ischemic–reperfusion injury, but the underlying mechanism is not fully understood. The current study investigated the role of reactive oxygen species–mediated upregulation of endogenous antioxidant enzymes in the generation of a protective effect induced by ischemic postconditioning against spinal cord reperfusion injury in the rabbit. Methods New Zealand White rabbits were randomly allocated to sham, ischemia–reperfusion, and postconditioning groups (3 cycles of 30 seconds of reperfusion and 30 seconds of occlusion during the onset of reperfusion). Spinal cord ischemia was induced by clamping the infrarenal abdominal aorta for 20 minutes in the ischemia–reperfusion and postconditioning groups. Forty-eight hours after reperfusion, the neurologic status of the lower limbs was assessed. Blood samples were collected for analysis of serum neuron-specific enolase levels, and the lumbar spinal cord segments (L5-7) were harvested for histopathologic and antioxidant enzyme activities and mRNA analysis with or without administration of N-2-mercaptopropionylglycine (an effective oxygen free radical scavenger) given at different reperfusion times. Results Continuous administration of N-2-mercaptopropionylglycine for 13 minutes, starting at 10 minutes before (but not 10 minutes after) the beginning of reperfusion, attenuated the neuroprotective effect of postconditioning against spinal cord ischemia and reversed the increase in activity of the antioxidant enzymes superoxide dismutase and catalase in spinal cord tissue subjected to ischemic postconditioning. Conclusions The results indicate that reactive oxygen species–triggered upregulation of endogenous antioxidant enzyme activities may be involved in the mechanism of neuroprotection of ischemic postconditioning.

The aim of this study is to examine the role of one of the two-pore (2P) domain K(+) channels, TREK (TWIK-related K(+) channels, TREK)-1, mediated neuroprotection on spinal cord afforded by isoflurane preconditioning. In Experiment 1, male Sprague-Dawley rats were randomly assigned to control (Con) group, an isoflurane preconditioning (Iso) group, and sham group. Twenty-four hours after the last pretreatment, spinal cord ischemia was induced in Con and Iso groups. Neurobehavioral testing and histopathologic examination were performed after reperfusion. In Experiment 2, the expression of the TREK1 in the spinal cord was assessed by immunohistochemistry, Western blot and real-time polymerase chain reaction. In Experiment 3, Amiloride, a blocker of stretch-sensitive channels, was administered intraperitoneally immediately prior to each isoflurane preconditioning. Iso group showed a significant reductions in motor deficit index as well as increases in the number of normal neurons compared with the Con group. The expression of TREK1 protein and the level of mRNA after ischemia were higher in the rats of the Iso group than those in the Con group. Amiloride pretreatment abolished the protective effects of Iso preconditioning. These finding indicate that isoflurane preconditioning had a neuroprotective effect against spinal cord ischemia reperfusion injury. These effects may be mediated through the TREK1 pathway.

Ischemic postconditioning (IPost) has been shown to attenuate cerebral ischemia–reperfusion injury. However, the mechanism remains elusive. Because opening of the mitochondrial permeability transition pore (MPTP) is a crucial determinant of cell death after ischemia–reperfusion, we hypothesized that the neuroprotective effect of IPost may be associated with inhibition of MPTP opening. In part 1 of this study, pentobarbital-anesthetized rats subjected to middle cerebral artery occlusion for 90 min, followed by reperfusion for 72 h, were assigned to receive one of the following treatments: three cycles of IPost (15 s each), intracerebroventricular injection of saline (control), administration of the MPTP inhibitor cyclosporin A (CsA) (2 μmol/L, 15 μL) or its vehicle alcohol, administration of the MPTP opener atractyloside (Atr) (2 mmol/L, 15 μL), or IPost plus CsA/Atr treatment. Neurological deficit scores (NDS) and infarct volumes were assessed. Mitochondrial ultrastructure and swelling were also examined after reperfusion. In part 2, control and IPost groups underwent ischemia (90 min) and reperfusion (15 min). CsA and Atr groups were treated as described in part 1. Brain mitochondria were isolated after reperfusion and MPTP activity was evaluated. IPost or CsA treatment significantly improved NDS and reduced infarction volume, while Atr reversed the neuroprotective effects of IPost, and attenuated the decrease in mitochondrial swelling induced by IPost or CsA. Thus, inhibiting MPTP opening may play a crucial role in the neuroprotective effects of IPost, which may have potential clinical value against cerebral ischemia–reperfusion injury.

Antiangiogenic therapies have shown varying results partly because each tumor type secretes a distinct panel of angiogenic factors to sustain its own microvascular network. In addition, recent evidence demonstrated that tumors develop resistance to antiangiogenic therapy by turning on alternate angiogenic pathways when one pathway is therapeutically inhibited. Here, we test the hypothesis that expression of a caspase-based artificial death switch in tumor-associated endothelial cells will disrupt tumor blood vessels and slow down tumor progression irrespective of tumor type. Adenoviral vectors expressing inducible Caspase-9 (iCaspase-9) under transcriptional regulation with the endothelial cell-specific vascular endothelial growth factor receptor-2 (VEGFR2) promoter (Ad-hVEGFR2-iCaspase-9) induced apoptosis of proliferating human dermal microvascular endothelial cells (HDMECs), but not human tumor cells (UM-SCC-17B, head and neck squamous cell carcinoma; HepG2, hepatocellular carcinoma; PC-3, prostate adenocarcinoma; SLK, Kaposi's sarcoma; MCF-7, breast adenocarcinoma). Notably, apoptosis was dependent upon activation of iCaspase-9 with the dimerizer drug AP20187. Local delivery of Ad-hVEGFR2-iCaspase-9 followed by intraperitoneal injection of AP20187 ablated tumor microvessels and inhibited xenografted tumor growth in all tumor models evaluated here. We conclude that a cancer gene therapy strategy based on a transcriptionally targeted viral vector expressing an inducible caspase allows for selective and controlled ablation of microvessels of histopathologically diverse tumor types.

Recent studies have demonstrated that adiponectin (APN) attenuates cerebral ischemic/reperfusion via globular adiponectin (gAD). However, the therapeutic role of gAD in cerebral ischemic injury in type 1 diabetes mellitus (T1DM) remains unclear. Our results showed that gAD improved neurological scores and reduced the infarct volumes in the 8-week T1DM (T1DM-8W) mice, but not in the 2-week T1DM (T1DM-2W) mice. Moreover, the ischemic penumbra APN levels increased and peaked in T1DM-2W mice and reduced to normal in T1DM-8W mice, while the APN receptor 1 (AdipoR1) expression change was the opposite. Administration of rosiglitazone in T1DM-2W mice up-regulated the expression of AdipoR1 and restored the neuroprotection of gAD, while intracerebroventricular injection of AdipoR1 small interfering RNA (siRNA) in T1DM-8W mice reversed it. Furthermore, the expression of p-PERK, p-IRE1 and GRP78 were increased whereas the expressions of CHOP and cleaved caspase-12 as well as the number of apoptotic neurons were decreased after gAD treatment in T1DM-8W mice. These beneficial effects of gAD were reversed by pretreatment with AdipoR1 siRNA. These results demonstrated a dynamic dysfunction of APN/AdipoR1 accompanying T1DM progression. Interventions bolstering AdipoR1 expression during early stages and gAD supplementation during advanced stages may potentially reduce the cerebral ischemic injury in diabetic patients.

Recent studies indicate that adiponectin can attenuate cerebral ischemic lesions via its functional area located in the C-terminal globular domain, which is called globular adiponectin (gAD). However, the mechanisms underlying this action remain unclear. In this study, we investigated the antioxidant properties of gAD during cerebral ischemia. Adult male C57BL/6 mice received an intracerebral injection of gAD with or without tetrabromocinnamic acid (TBCA, a NADPH oxidase activator). Mice were subjected to middle cerebral artery occlusion (MCAO) after gAD injection. Infarct volume, neurological function, the activity of antioxidant enzymes (superoxide dismutase [SOD], catalase), the content of malondialdehyde (MDA), and the expression of Bax, Bcl-2, cleaved caspase-3 and NADPH oxidase 2 (NOX2) were examined at 24h after MCAO. Infarct volume was attenuated in gAD-transduced mice when compared with mice in the MCAO group, with significant improvement in neurological function. In addition, neuronal apoptosis was attenuated, along with the expression of Bax/Bcl-2 and cleaved caspase 3. Furthermore, the activities of SOD and catalase increased, and the content of MDA reduced. However, TBCA blocked the effect of gAD on cerebral protection and its antioxidant abilities. Taken together, these results demonstrate that the neuroprotective action of gAD may result from the promotion of antioxidant capacity by inhibiting the NOX2 signaling system.

SUMMARY Aims: In acute stroke, neurological damage is due to oxidative stress and neuronal apoptotic death. This study investigated whether Nogo-A 290-562 residues region (M9), fused to the transduction domain of the HIV trans-activator (TAT) protein, is neuroprotective against cerebral ischemia and the mechanisms. Methods: Transient focal cerebral ischemia was induced by middle cerebral artery occlusion in male C57BL/6J mice. TAT-M9, its mutation or vehicle was applied via intraperitoneal injection at the onset of reperfusion. The neurobehavioral scores, infarction volumes, neuronal apoptosis, and the ratio of Bax/Bcl-2 were evaluated. Malondialdehyde (MDA), reactive oxygen species (ROS) levels, and NADPH oxidase activation were measured in the presence or absence of the NADPH oxidase inhibitor apocynin or activator tetrabromocinnamic acid (TBCA). Results: Immunofluorescence results confirmed that TAT-M9 was transduced into brain parenchyma, and it significantly improved neurological behavior, reduced infarct volumes, protected neuronal cells from apoptosis, inhibited activation of NADPH oxidase, and decreased MDA and ROS contents. Furthermore, apocynin imitated the beneficial effects of TAT-M9, while TBCA abolished them. Conclusions: Our results demonstrate that TAT-M9 administration attenuates cerebral ischemia by inhibiting NADPH oxidase-mediated oxidative damage and neuronal apoptosis in mice. TAT-M9 may be a potential treatment for cerebrovascular disease.