The effects of D-allose on transient ischemic neuronal death and analysis of its mechanism.

The present study investigates the neuroprotective effects of d-allose, a rare sugar, against ischemia/reperfusion injury in a gerbil model. Transient forebrain ischemia was induced by occlusion of the bilateral common carotid arteries for 5 min. D-Allose was intravenously injected before and after ischemia (200 mg/kg). Extracellular glutamate and lactate release from the gerbil brain, and PO2 profiles were monitored during ischemia and reperfusion. We also examined neuronal death and oxidative damage in the hippocampus one week after ischemia reperfusion, and investigated functional outcome. D-Allose administration suppressed glutamate and lactate release compared to vehicle controls. Brain damage, 8-OHdG levels (a marker of oxidative stress) and locomotor activities were significantly decreased by D-allose treatment. The present results suggest that d-allose reduces delayed neuronal death and behavioral deficits after transient ischemia by changing cerebral metabolism and inhibiting oxidative stress.

Neuroprotection of granulocyte colony-stimulating factor during the acute phase of transient forebrain ischemia in gerbils.

The present study investigates the potential protective effects of granulocyte colony-stimulating factor (G-CSF) and underlying mechanisms in a gerbil model of global cerebral ischemia. We examined neuronal death, inflammatory reaction and neurogenesis in hippocampus 72 h after transient forebrain ischemia and investigated functional deficits. G-CSF was administered intraperitoneally 24 h before ischemia and then daily. Treatment with G-CSF at 25-50 µg/kg significantly reduced neuronal loss in the hippocampus CA1 area but not at 10 ug/kg. G-CSF at 50 µg/kg significantly decreased the level of TNF-α, the number of Iba1 (microglia marker) positive cells and reduced locomotor activity 72 h after transient forebrain ischemia. Furthermore, the number of DCX-positive cells in the hippocampal dentate gyrus increased in with G-CSF treatment. Our findings indicate that G-CSF reduces hippocampal neuronal cell death dose-dependently and attenuates sensorimotor deficits after transient forebrain ischemia. These neuroprotective effects of G-CSF may be linked to inhibition of inflammation and possibly increased neurogenesis in the hippocampus.

Ameliorative effects of yokukansan on behavioral deficits in a gerbil model of global cerebral ischemia.

The aim of this study was to investigate the neuroprotective effects of yokukansan, a traditional Kampo medicine, on the behavioral dysfunction induced by cerebral ischemia/reperfusion injury in gerbils. Gerbils were treated with yokukasan by oral gavage for 30 days, once per day, until the day before induction of ischemia, which was induced by occluding the bilateral common carotid artery for 5 min. The effects of yokukansan (50, 100 and 300 mg/kg) were examined by measuring neuronal damage and behavioral deficits (locomotor activity, 8-arm radial maze task). The anti-inflammatory and anti-oxidant properties of yokukansan were also examined. Administration of yokukansan at 300 mg/kg significantly reduced hippocampal neuronal death after brain ischemia, inhibited the ischemia-induced inflammatory response and DNA oxidative damage. Yokukansan also reduced ischemia-induced locomotor hyperactivity and improved memory impairment. These findings suggest that yokukansan can inhibit the inflammatory response, oxidative damage and subsequent neuronal death induced by cerebral ischemia/reperfusion injury, and also can contribute to improvement in neurological deficits following such injury.

Edaravone, a free radical scavenger, attenuates behavioral deficits following transient forebrain ischemia by inhibiting oxidative damage in gerbils.

The present study investigates the neurological protective effects of edaravone against global brain ischemia. Gerbils were treated with edaravone (3mg/kg; i.p.) 30min before transient forebrain ischemia, which was induced by occluding the bilateral common carotid artery for 5min. The effects of edaravone were examined by measuring neuronal damage and behavioral deficits. Hexanoyl-lysine adduct (HEL) and 8-hydroxy-2'-deoxyguanosine (8-OHdG), oxidative stress markers, were also examined to assess the anti-oxidative effects of edaravone. Edaravone treatment significantly inhibited both lipid and DNA oxidative damage 72h after ischemia, and decreased neuronal damage. Edaravone also significantly reduced the locomotor activity deficit 72h after ischemia and improved memory impairment. These findings suggest that edaravone inhibits oxidative stress and attenuates neuronal damage induced by transient forebrain ischemia in gerbils and which may contribute to improvements in behavioral deficits.

Anti-oxidative effects of d-allose, a rare sugar, on ischemia-reperfusion damage following focal cerebral ischemia in rat.

The present study investigates the anti-oxidative effects of D-allose on ischemic damage. Rats were subjected to transient middle cerebral artery occlusion (MCAO) for 1 h under pentobarbital anesthesia. D-allose was intravenously infused during occlusion and a further 1 h after reperfusion (400 mg/kg). The effects of D-allose on focal cerebral ischemia were examined by measuring brain damage (infarction and atrophy volume) and behavioral deficits 7 days after MCAO. In another set of rats, apurnic/apyrimidic abasic sites (AP-sites) and 8-hydroxy-2'-deoxyguanosine (8-OHdG), oxidative stress markers, were investigated 24 h after MCAO to examine the anti-oxidative effects of D-allose. Brain damage and behavioral deficits were significantly decreased by D-allose administration compared to vehicle. The number of AP-sites and 8-OHdG levels were also reduced by D-allose. Thus, the present study suggests that D-allose has anti-oxidative effects and induces neuroprotection in focal cerebral ischemia.

Eicosapentaenoic acid prevents memory impairment after ischemia by inhibiting inflammatory response and oxidative damage.

Previous studies have demonstrated that the generation of reactive oxygen species and an excessive inflammatory reaction are involved in the progression of neural damage following brain ischemia. In this study, we focused on the anti-inflammatory and antioxidant properties of eicosapentaenoic acid (EPA). Gerbils were treated intraperitoneally with 500 mg/kg of EPA ethyl for 4 weeks until the day of forebrain ischemia, which was induced by occluding the bilateral common carotid artery for 5 minutes. In the first part of the 2-part experiment, the effect of EPA treatment was evaluated using hematoxylin and eosin staining and deoxynucleotidyl transferase-mediated dUTP nick-end labeling as a marker of cell death (n=3 per group). The inflammatory reaction was evaluated using anti-Iba1 immunohistochemistry, a marker of microglial activation (n=3 per group), and detection of 8-hydroxyl-2'-deoxyguanosine, a marker of oxidative DNA damage (n=4 per group). In the second part of the experiment, the effect of EPA treatment on memory function was examined using an 8-arm radial maze (n=6 per group). EPA treatment significantly inhibited DNA oxidative damage (P < .05) and accumulation of Iba1-positive cells in the CA1 area at 12 and 72 hours after the induction of ischemia, and also decreased apoptotic neurons and neuronal death (P < .001) at 72 hours after ischemia. EPA treatment also significantly improved memory function (P < .05). These findings suggest that EPA inhibits the inflammatory reaction and oxidative damage occurring after ischemic brain injury, and also may contribute to the prevention of neural damage and memory impairment following such injury.

3CB2, a marker of radial glia, expression after experimental intracerebral hemorrhage: role of thrombin.

The current study examined 3CB2, a marker of radial glia, expression after intracerebral hemorrhage (ICH) and intracerebral thrombin injection. Adult male Sprague-Dawley rats received an intracaudate injection of 100 microl autologous whole blood or 5 U thrombin (50 microl). Animals were sacrificed for Western blotting to quantify 3CB2 expression, and for single and double labeling immunohistochemistry to identify which cells express 3CB2. Behavioral examinations (forelimb placing test and corner turn test) were performed as an evaluation of function. By Western blot analysis, 3CB2 was strongly expressed at day 3 and the expression persisted for at least 1 month. Intracerebral injection of thrombin also upregulated 3CB2. Hirudin, a thrombin inhibitor, reduced ICH-induced 3CB2 expression. By immunohistochemistry, 3CB2 immunoreactivity was present in large numbers of glial cells surrounding the hematoma at 1 day after ICH. One month later, 3CB2 immunoreactivity was co-localized with a neuronal precursor marker, TUC-4. ICH-induced behavioral deficits were severe at 1, 3 and 7 days, with recovery at 1 month. The forelimb placing test score paralleled changes in 3CB2 expression. ICH-induced 3CB2 expression in glial cells may reflect an early response of these cells to injury, while the delayed expression in neurons might be a part of the adaptative response to injury perhaps participating in recovery of function. Thrombin has a role in 3CB2 expression in ICH.

Differential gene expression of 36-kDa microfibril-associated glycoprotein (MAGP-36/MFAP4) in rat organs.

By using quantitative Western blot analysis and the real time polymerase chain reaction technique, we investigated the differential gene expression of microfibril-associated glycoprotein (MAGP-36) in rat organs. The gene was expressed highly in sites rich in elastic fibers, such as aorta, skin, and esophagus. However, MAGP-36 was also expressed highly in some other sites containing no elastic fibers. In lung and trachea, the expression levels of MAGP-36 mRNA were about seven times higher than those in other elastic tissues, although the protein abundances were almost at the same levels as other elastic tissues. MAGP-36 seemed to be secreted outside these organs. In brain, kidney, and spleen, although the expression levels of MAGP-36 mRNA were low, substantial amounts of MAGP-36 protein were detected. An immunohistochemical study revealed that MAGP-36 was present at the brush border of the S3 segment of proximal tubules in kidney. Since MAGP-36 is known to bind to mannan, MAGP-36 might be involved in mannose transport in the S3 segment. Thus, MAGP-36 might be multifunctional and present in a wide variety of sites in various organs.

36-kDa microfibril-associated glycoprotein (MAGP-36) is an elastin-binding protein increased in chick aortae during development and growth.

MAGP-36 was discovered in porcine aorta in 1989 and is thought to be one of the microfibril-associated proteins. MAGP-36 has been localized on the surface of elastic fibers or laminae in immunohistochemical studies. However, its functional role in the aorta is obscure. Herein, we report on the binding activity of MAGP-36 to components of the aortic wall and its accumulation pattern in the aorta during development and growth. In vitro, MAGP-36 bound to elastin and collagen in a Ca(2+)-dependent manner, and mediated the adhesion of human aortic smooth muscle cells. This cell adhesion mostly depended on the RGD-containing domain of MAGP-36. We examined the accumulation of MAGP-36 with quantitative Western blot analysis and immunoelectron microscopy in chick aortae during development and growth. The amount of MAGP-36 increased on the surface of elastic fibers or laminae between days 14 and 34 after the start of incubation, and reached a plateau at about 53 days. This accumulation of MAGP-36 roughly correlated with an increase in blood pressure for this period. Thus, MAGP-36 might be a bridging protein that connects elastin to other components of the aortic wall and might play a role in maintaining the integrity of the aortic structure under arterial pressure.