Neuroprotective effect of treatment with human albumin in permanent focal cerebral ischemia: histopathology and cortical perfusion studies.

In recent experimental studies, we demonstrated a highly beneficial neuroprotective effect of moderate- to high-dose human albumin treatment of transient focal cerebral ischemia, but we did not define the effect of albumin therapy in permanent focal cerebral ischemia. In this study, anesthetized Sprague-Dawley rats were subjected to permanent middle cerebral artery occlusion by retrograde insertion of an intraluminal nylon suture coated with poly-L-lysine. Albumin was administered i.v. at 2 h after onset of middle cerebral artery occlusion, in doses of either 1.25 (n=8) or 2.5 g/kg (n=6). In a separate group of animals, albumin (2.5 g/kg) was given 1 h after middle cerebral artery occlusion (n=6). Vehicle-treated rats (n=6) received 0.9% saline in equivalent volumes. Neurological status was evaluated during and 24 h after middle cerebral artery occlusion. One day after middle cerebral artery occlusion, infarct volumes and brain edema were determined. In a separate group of animals, cortical perfusion was assessed by Laser-Doppler perfusion imaging. Albumin (1.25 g/kg; n=3) or vehicle (sodium chloride 0.9%; n=3) was administered at 2 h after onset of middle cerebral artery occlusion. Higher-dose albumin therapy (2.5 g/kg) significantly improved the neurological score compared to vehicle rats at 24 h, when administered at either 1 or 2 h after middle cerebral artery occlusion. Total infarct volume was reduced by albumin (2.5 g/kg given at 2 h) by 32% compared with vehicle-treated rats. Both albumin doses (1.25 and 2.5 g/kg) significantly reduced cortical and striatal infarct areas at several coronal levels when administered at 2 h after middle cerebral artery occlusion. Brain swelling was not affected by albumin treatment. Cortical perfusion declined during middle cerebral artery occlusion in both groups. Treatment with albumin led to 48% increases in cortical perfusion (P<0.002), but saline caused no change. These results support a beneficial effect of albumin therapy in permanent focal cerebral ischemia.     

Adenosine kinase inhibition protects brain against transient focal ischemia in rats

Endogenous adenosine released locally during cerebral ischemia is neuroprotective, and agents which decrease adenosine inactivation may potentiate its protective effects. The effects of 5′-deoxy-5-iodotubercidin (5′d-5IT), an inhibitor of the adenosine-catabolizing enzyme, adenosine kinase, were studied in male Wistar rats subjected to 2 h of transient middle cerebral artery occlusion. 5′d-5IT or the vehicle (10% DMSO in saline) was administered i.p. 30 min before, and 2 h and 6 h after the induction of middle cerebral artery occlusion. The infarct volume was determined using 2,3,5-triphenyltetrazolium chloride staining 48 h after middle cerebral artery occlusion. The infarct volume was significantly reduced in rats treated with 1.85 mg/kg×3 (57% reduction, P<0.001) or 1.0 mg/kg×3 (34% reduction, P<0.05), but not 0.3 mg/kg×3 5′d-5IT compared to vehicle-treated rats. The reduction of infarct volume was accompanied by a significant improvement in behavioral measures of neurological deficit. These data further support a role of adenosine in neuroprotection and suggest that adenosine kinase inhibition may be a useful approach to the treatment of focal cerebral ischemia.     

The broad-spectrum cation channel blocker pinokalant (LOE 908 MS) reduces brain infarct volume in rats: a temperature-controlled histological study

Activation of cation channels conducting Ca2+, Na+ and K+ is involved in the pathogenesis of infarction in experimental focal cerebral ischaemia. Pinokalant (LOE 908 MS) is a novel broad-spectrum inhibitor of several subtypes of such channels and has previously been shown to improve the metabolic and electrophysiologic status of the ischemic penumbra and to reduce lesion size on magnetic resonance images in the acute phase following middle cerebral artery occlusion in rats. The purpose of the present study was to investigate whether these beneficial effects of pinokalant are translated into permanent neuroprotection in terms of a reduction in infarct size one week after middle cerebral artery occlusion in rats. Halothane-anaesthetized male Wistar rats subjected to permanent distal middle cerebral artery occlusion were randomly assigned to one of two treatment groups: 1) Control (vehicle intravenous loading dose followed by infusion); 2) Pinokalant (0.5 mg/kg intravenous loading dose followed by infusion of 1.25 mg/kg/hr). Infusions started 30 min. after middle cerebral artery occlusion and were continued for 24 hr. Body temperature and mean arterial blood pressure were monitored by telemetry during this period and the spontaneous temperature after course in control rats established in other experiments was imitated. Seven days later histological brain sections were prepared and the infarct volumes measured. Body temperature did not differ between the groups. Mean arterial blood pressure was slightly higher in the pinokalant group. Pinokalant treatment significantly reduced cortical infarct volume from 33.8+/-15.8 mm3 to 24.5+/-13.1 mm3 (control group versus pinokalant group, P=0.017, t-test). Taking the effective drug plasma concentration established in other experiments into account revealed that in rats with plasma concentrations within the therapeutic interval, infarct volumes were further reduced to 17.9+/-7.5 mm3 (P<0.005).     

白三烯受体拮抗剂ONO—1078对大鼠局灶性脑缺血的神经保护作用

AIM: To determine whether ONO-1078 (pranlukast), a potent leukotriene receptor antagonist, has neuroprotective effect on focal cerebral ischemia in the rat. METHODS: Focal cerebral ischemia was induced by 30 min of middle cerebral artery (MCA) occlusion and followed by 24 h reperfusion. ONO-1078 (0.003-1.0 mg/kg) or vehicle (saline 1 mL/kg) was ip injected 30 min before MCA occlusion and 2 h after reperfusion. The neurological score, infarct volume, neuron density (in cortex, hippocampus, and striatum), brain edema, and albumin exudation around the vessels were determined 24 h after reperfusion. RESULTS: ONO-1078 slightly improved the neurological deficiency, and dramatically decreased infarct volume and neuron loss which showed a bell shaped dose response effect with highest effect at doses of 0.01-0.3 mg/kg. Enlargement of the ischemic hemisphere and albumin exudation were inhibited at doses of 0.01-1.0 mg/kg. CONCLUSION: ONO-1078 has the protective effect on focal cerebral ischemia in rats, which is partially attributed to the inhibition of brain edema. This may represent a novel approach to the treatment of acute cerebral ischemia with cysteinyl leukotriene receptor antagonists.     

In vivo neuroprotective effects of ACEA 1021 confirmed by magnetic resonance imaging in ischemic stroke

The neuroprotective activity of ACEA 1021 (5-nitro-6,7-dichloro-1,4-dihydro-2,3-quinoxalinedione; licostinel), a selective antagonist at the strychnine-insensitive glycine site associated with the NMDA receptor complex, has been investigated in various models of focal cerebral ischemia. In isoflurane-anaesthesised Wistar rats with permanent ipsilateral carotid artery ligation and transient middle cerebral artery occlusion (duration of occlusion, 2 h) followed by reperfusion (24 h), intravenous administration of ACEA 1021 (bolus: 10 mg/kg, 15 min after the onset of middle cerebral artery occlusion; infusion: 7 mg/kg/h for 6 h beginning 30 min after occlusion of the artery) produced a 32% reduction in infarct volume. Similarly, in Sprague-Dawley rats with transient middle cerebral artery occlusion (2 h) followed by 24 h of reperfusion, identical treatment with ACEA 1021 decreased infarct size by 39%. Magnetic resonance imaging (MRI) confirmed these effects in the transient model, in that infarct volume observed using apparent diffusion coefficient (ADC) maps was significantly smaller after 24 h in the ACEA 1021-treated rats compared with Tris-treated controls. Furthermore, the increase in perfusion signal intensity after reperfusion was more pronounced in the ACEA 1021-treated rats than in controls. In Fisher 344 rats with permanent occlusion of the middle cerebral artery, ACEA 1021 induced a dose-related decrease in infarct volume, which was associated with an improvement in neurological outcome as measured by the rope suspension procedure. Administration of the same dose regimen, as above, in Fisher rats with permanent middle cerebral artery occlusion reduced infarct volume by 68%. This dose was as effective when administration was delayed for 2 h. In mice with permanent middle cerebral artery occlusion, ACEA 1021 (5 mg/kg, i.v., 5 min after occlusion; 30 mg/kg, s.c., 1 and 4 h post-middle cerebral artery occlusion) decreased infarct size by 42%. The consistent anti-ischemic effects of ACEA 1021 make it a valuable compound for exploratory stroke research.     

Novel complement C1 inhibitor BSF468248 does not improve brain damage after cortical vein occlusion

BSF468248 is a novel potent complement C1 inhibitor. To determine whether BSF468248 is effective against focal cerebral ischemia, we evaluated the change of cerebral blood flow (CBF) and infarction volume using a photochemically-induced cortical vein occlusion model in rats in blind studies. In 22 Wistar rats, two adjacent cortical veins were occluded by photochemical thrombosis and fiberoptic illumination under controlled anesthesia and ventilation. Just after the occlusion, BSF468248 or physiological saline was administrated. In the low-dose study, a treatment group (n = 7) was administered BSF468248 1 mg/kg bolus and 1 mg/kg continuously for 30 min. The same volume of saline was given to a vehicle group (n = 5). In the high-dose study, a treatment group (n = 5) was administrated BSF468248 1 mg/kg bolus and 12 mg/kg continuously for 180 min. The same volume of saline was given to a vehicle group (n = 5). During the experiment, regional cerebral blood flow (rCBF) was measured in both the low-dose study (120 min) and the high-dose study (180 min). Seven days after the experiment, the animals were killed in order to evaluate the infarct volume. The rCBF at the end of the experiment showed a similar decrease in both the low-dose study (at 120 min: treatment group: 66.5 +/- 10.2%; vehicle group: 69.3 +/- 10.2%) and the high-dose study (at 180 min: treatment group: 62.1 +/- 7.5%; vehicle group: 65.1 +/- 12.3%), with no significant differences (t-test). The infarct volume also showed no significant difference in either group of the low-dose study (treatment group: 3.46 +/- 0.84 mm3; vehicle group: 3.56 +/- 1.40 mm3) or the high-dose study (treatment group: 2.27 +/- 0.43 mm3; vehicle group: 1.76 +/- 0.31 mm3). Our study found that BSF468248 is not effective in improving the rCBF and the infarct volume following focal cerebral ischemia.     

Effect of mergocriptine on postischemic brain damages.

The effects of mergocriptine (2-methyl-a-ergocryptine; CBM36-733; CAS 81968-16-3) on ischemia-induced brain damages were studied using both a global and a focal ischemia model. First, immediately after 5 min of forebrain ischemia induced by ligation of the bilateral carotid arteries of Mongolian gerbils, the animals were intraperitoneally injected with 3 mg/kg or 10 mg/kg CBM36-733. Seven days after ischemia, perfusion-fixed brains were processed by conventional histology. The number of neurons per mm in the CA 1 pyramidal cell layer was calculated and they were labelled neuronal density. In the control group, the neuronal density was 69.7 +/- 7.2 (mean +/- SEM/mm), in the vehicle group and 3 mg/kg of CBM36-733 treated group, they were 12.2 +/- 4.4 and 11.6 +/- 5.1, respectively. The neuronal density in the 10 mg/kg of CBM36-733 treated group was 42.2 +/- 8.4. These data indicate that 10 mg/kg of CBM36-733 protects on the CA 1 neurons against ischemia induced delayed neuronal death. Second, the effect of long-term administration of 3 mg/kg CBM36-733 on focal brain ischemia of the rats was studied by measuring regional cerebral blood flow and glucose metabolism by autoradiograms. After 90 min of middle cerebral artery occlusion, the rats were intraperitoneally injected with 3 mg/kg of CBM36-733 every day for 2 weeks. There were no significant differences in cerebral blood flow and glucose metabolism between the treated group and the vehicle group.(ABSTRACT TRUNCATED AT 250 WORDS)     

DY-9760e, a calmodulin antagonist, reduces brain damage after permanent focal cerebral ischemia in cats

DY-9760e (3-[2-[4-(3-chloro-2-methylphenyl)-1-piperazinyl]ethyl]-5,6-dimethoxy-1-(4-imidazolylmethyl)-1H-indazole dihydrochloride 3.5 hydrate), a calmodulin antagonist, provides protection against Ca(2+) overload-associated cytotoxicity and brain injury after cerebral ischemia in rats. In this study, we assessed the effect of DY-9760e on ischemic infarct volume in cats subjected to permanent focal cerebral ischemia. DY-9760e was infused for 6 h, beginning 5 min after occlusion of the middle cerebral artery. The infarct volume was measured at the end of drug infusion. DY-9760e, at the dose of 0.25 but not 0.1 mg/kg/h, significantly reduced cerebral infarct volume without affecting any physiological parameters, and its protective effect was mainly evident in the cerebral cortex, where the penumbra, a salvageable zone, exists. The present study demonstrates that DY-9760e protects against brain injury after focal ischemia in a gyrencephalic animal as well as in the rodents reported previously and suggests its therapeutic value for the treatment of acute stroke.     

DY-9760e, a novel calmodulin antagonist, reduces infarction after permanent focal cerebral ischemia in rats

DY-9760e (3-[2-[4-(3-chloro-2-methylphenyl)-1-piperazinyl]ethyl]-5,6-dimethoxy-1-(4-imidazolylmethyl)-1H-indazole dihydrochloride 3.5 hydrate), a novel calmodulin antagonist, provides effective protection against Ca(2+) ionophore-induced cytotoxicity and brain injury induced by transient focal ischemia. In this study, we evaluated the effect of DY-9760e on ischemic infarct volume in rats subjected to permanent focal ischemia. DY-9760e (0.5 mg/kg/h for 6 h) significantly reduced the infarct volume when administered immediately after middle cerebral artery occlusion. Furthermore, this neuroprotection was also exerted by treatment with a 3-hour delay, implying that the therapeutic time window for this compound is at least 3 h. In addition, although treatment with 0.1 mg/kg/h for 24 h was ineffective, the combination of a loading dose of 0.3 mg/kg/h for 2 h followed by 0.1 mg/kg/h for 22 h yielded a significant reduction in infarct volume. Thus, prolonged infusion preceded by a loading dose is an efficacious dosing regimen for DY-9760e, especially at a low infusion rate. These data demonstrate the substantial neuroprotective effect of DY-9760e in a permanent focal ischemia model and indicate that this neuroprotectant may be of therapeutic value for the treatment of acute stroke.     

Effect of TTC-909 in a middle cerebral artery thrombosis model in stroke-prone spontaneously hypertensive rats

We investigated the effect of TTC-909, a preparation of the stable prostaglandin I(2) analogue clinprost (isocarbacyclin methylester; methyl 5-[(1S,5S,6R,7R)-7-hydroxy-6-[(E)-(S)-3-hydroxy-1-octenyl] bicyclo[3.3.0]oct-2-en-3-yl] pentanoate) incorporated into lipid microspheres, on infarct volume 24 h after photochemically induced thrombotic occlusion of the middle cerebral artery in stroke-prone spontaneously hypertensive rats (SHR). Under anesthesia, the photosensitizing dye rose bengal (20 mg/kg) was administered intravenously and photoirradiation with green light (wavelength 540 nm) on the middle cerebral artery above the rhinal fissure was achieved using a xenon lamp for 10 min. Infarct volume 24 h after the photochemically induced thrombotic occlusion of the middle cerebral artery was significantly larger in stroke-prone SHR than in Wistar rats. When TTC-909 in doses of 100, 300 and 900 ng/kg/h was intravenously infused for 3 h, starting immediately after the end of the 10-min photoirradiation, the infarct volume was dose-dependently reduced and was statistically significant at a dose of 900 ng/kg/h (p < 0.05). Ozagrel, a thromboxane A(2) synthetase inhibitor, significantly reduced the infarct volume. The model of photochemically induced thrombotic occlusion of the middle cerebral artery in stroke-prone SHR is very useful, because the cerebral infarction is large enough and reproducible. TTC-909 may be effective for the treatment of acute ischemic stroke.     

Effect of melatonin on ischemia reperfusion injury induced by middle cerebral artery occlusion in rats.

Free radicals have been implicated in neuronal injury during ischemia reperfusion in stroke. Therefore, in the present study, melatonin, a potent antioxidant, was studied in male Wistar rats subjected to 2 h of transient middle cerebral artery occlusion. Melatonin (10, 20 and 40 mg/kg i.p.) was administered four times in an animal at the time of middle cerebral artery occlusion, 1 h after middle cerebral artery occlusion, at the time of reperfusion and 1 h after reperfusion. Two hours after reperfusion, rats were euthanized for estimation of oxidative stress markers (malondialdehyde and reduced glutathione). The doses of 20 and 40 mg/kg of melatonin significantly attenuated the raised level of malondialdehyde (287+/-28, 279+/-52 nmol/g wet tissue, respectively) as compared to the levels (420+/-61 nmol/g wet tissue) in vehicle-treated middle cerebral artery-occluded rats. There was an insignificant change in levels of reduced glutathione at these doses (95+/-42, 88.7+/-36 microg/g wet tissue, respectively) as compared to those in the vehicle-treated middle cerebral artery-occluded rats (108.21+/-21 microg/g wet tissue). However, there was an insignificant difference between 20 and 40 mg/kg treated rats. Therefore, the dose of 20 mg/kg i.p. was used to evaluate the neuroprotective effect by using diffusion-weighted imaging (30 min after reperfusion), assessing the neurological deficit (24 h after middle cerebral artery occlusion) and estimating oxidative stress markers (72 h after middle cerebral artery occlusion). In the 20 mg/kg melatonin-treated group, percent ischemic lesion volume on diffusion-weighted imaging was significantly attenuated (9.8+/-3.9) as compared to that in the vehicle-treated group (21.4+/-4.7). The neurological deficit was significantly improved in the melatonin group (1.8+/-0.06) as compared to that in the vehicle-treated (2.9+/-0.38) group. The level of malondialdehyde (321.4+/-31 nmol/g wet tissue) and reduced glutathione (142.6+/-13 microg/g wet tissue) in the melatonin-treated group was also significantly decreased as compared to the level of malondialdehyde (623+/-22 nmol/g wet tissue) and reduced glutathione (226.6+/-19 microg/wet tissue) in the vehicle-treated group. The present study indicates that melatonin has a neuroprotective action in focal ischemia, which may be attributed to its antioxidant property.     

Combination of low dose ethanol and caffeine protects brain from damage produced by focal ischemia in rats

Caffeine and ethanol are two commonly overused psychoactive dietary components. The purpose of this study was to assess the effects of acute, chronic, oral (p.o.) and intravenous (i.v.) caffeine, ethanol and their combination on infarct volume following focal ischemia in rats. Rats received treatment either p.o. 3 h and 1 h before, or by i.v. infusion for 2.5 h beginning 30-180 min after, ischemia. There were six acute treatment groups. (1) oral dH2O (control); (2) oral caffeine (10 mg/kg); (3) oral ethanol (0.65 g/kg total); (4) oral ethanol plus caffeine; (5) intravenous saline; and (6) intravenous ethanol (0.65 g/kg) plus caffeine (10 mg/kg) in saline. A 7th group received oral ethanol plus caffeine for three weeks prior to ischemia. After 3 h of left MCA/CCA occlusion and 24 h reperfusion, infarct volume was determined. Control animal infarct volume was 102.4+/-42.0 mm3. Oral caffeine alone had no effect (122.4+/-30.2 mm3). Oral ethanol alone exacerbated infarct volume (177.2+/-27.8 mm3). Oral caffeine plus ethanol almost entirely eliminated the damage (17.89+/-10.41 mm3). When i.v. treatment with ethanol plus caffeine was initiated at 30, 60, 90 and 120 minutes post-ischemia the infarct volume was reduced by 71.7%, 49.8%, 64.8% and 47.1%, respectively. Chronic daily oral ethanol plus caffeine prior to ischemia eliminated the neuroprotection seen with acute treatment. These studies indicate that ethanol, which by itself aggravates cerebral ischemia, and caffeine, when combined together immediately before or for 2 h after focal stroke, reduces ischemic damage.     

Caffeic acid ameliorates early and delayed brain injuries after focal cerebral ischemia in rats

AIM:To investigate the effects of caffeic acid on early and delayed injuries after focal cerebral ischemia in rats, and the possible relation to 5-lipoxygenase inhibition. METHODS: Transient focal cerebral ischemia was induced by middle cerebral artery occlusion in Sprague-Dawley rats. Caffeic acid (10 and 50 mg/kg) was ip injected for 5 d after ischemia. The brain injuries were observed, and the levels of cysteinyl leukotrienes and leukotriene B4 in the brain tissue were measured. RESULTS: Caffeic acid (50 mg/kg) ameliorated neurological dysfunction and neuron loss, and decreased infarct volume 24 h after ischemia; it attenuated brain atrophy, infarct volume, and particularly astrocyte proliferation 14 d after ischemia. In addition, it reduced the production of leukotrienes (5-lipoxygenase metabolites) in the ischemic hemispheres 3 h and 7 d after ischemia. CONCLUSION: Caffeic acid has protective effect on both early and delayed injuries after focal cerebral ischemia in rats; and this effect may partly relate to 5-lipoxygenase inhibition.     

侧脑室注射血管内皮生长因子抗体加重短暂性脑缺血后脑损伤

AIM: To clarify the role of vascular endothelial growth factor (VEGF) in neuronal damage induced by cerebral ischemia. METHODS: Expression of VEGF in adult rat brain was measured by immunohistochemistry. Transient middle cerebral artery occlusion (MCAO) model was induced by placing a nylon thread in the lumen of the internal carotid artery. The infarct volume was shown with 2,3,5-triphenyltetrazolium chloride (TTC) staining and quantitated by computer image analyzer with and without VEGF antibody treatment. RESULTS: VEGF expression was widely distributed in neuronal cells besides vascular endothelial cells, and the neuronal distribution of VEGF was specific. After intraventricular treatment with VEGF antibody (0.1 g.L-1 daily, for 7 d following the ischemia), infarct volume in the antibody treatment was increased versus vehicle-treated rats [(21.6 +/- 2.7 vs 16 +/- 6) mm3, P < 0.05] respectively. CONCLUSION: Intraventricular injection of VEGF antibody increased the infarct volume after focal cerebral ischemia in rats, suggesting that expression of neuronal VEGF may be one of neuronal protective mechanisms.     

Cilostazol, a phosphodiesterase 3 inhibitor, protects mice against acute and late ischemic brain injuries

Cilostazol, a selective inhibitor of phosphodiesterase 3, exerts neuroprotective effects on acute brain injury after cerebral ischemia in rats. However, it is unknown whether cilostazol affects the subacute or chronic ischemic injury. In the present study, we evaluated the dose- and time-dependent effects of cilostazol on acute ischemic brain injury and the long-lasting effect on the late (subacute/chronic) injury in mice with focal cerebral ischemia induced by transient middle cerebral artery occlusion. We found that pre-treatment of cilostazol (injected i.p. at 30 min before ischemia) significantly ameliorated the acute injury 24 h after ischemia, and the effective doses were 3-10 mg/kg. The post-treatment of cilostazol (10 mg/kg) was effective on the acute injury when it was injected 1 and 2 h after ischemia. In addition, for the late injury, post-treatment of cilostazol (10 mg/kg, i.p., for 7 consecutive days after ischemia) attenuated neurological dysfunctions, brain atrophy and infarct volume. It also inhibited astrocyte proliferation/glial scar formation and accelerated the angiogenesis in the ischemic boundary zone 7 and 28 days after ischemia. Thus, we conclude that cilostazol protects against not only the acute injury, but also the late injury in mice with focal cerebral ischemia; especially it can modify brain remodeling, astrogliosis and angiogenesis.     

Protective effect of Etoricoxib against middle cerebral artery occlusion induced transient focal cerebral ischemia in rats

Stroke is the third leading cause of global death and disability. Cyclooxygenase-2 mRNA has been shown to be up-regulated after stroke and also the time window of its expression extends from 4 to 12 h. The objective of this study was to elucidate the protective effect of Etoricoxib (a selective Cyclooxygenase-2 inhibitor) against transient middle cerebral artery occlusion induced behavioral, biochemical and histological alterations. Transient ischemia reperfusion significantly caused behavioral (neurological deficits, decreased locomotor activity and rotarod performance), biochemical (increased lipid peroxidation and nitrite concentration, while decreased superoxide dismutase and catalase activity) and histological (increased infarct volume) changes. Etoricoxib (3 and 10 mg/kg, i.p.) significantly reversed the alterations caused by cerebral ischemia however, 1 mg/kg dose was not found effective in any of the parameters. Finally, we can conclude that Etoricoxib has beneficial effects against transient middle cerebral artery occlusion model in rats. The present study indicates that Etoricoxib may be considered as a potential candidate in the treatment of stroke, clinically.     

Neuroprotective capabilities of Tanshinone IIA against cerebral ischemia/reperfusion injury via anti-apoptotic pathway in rats

Danshen, derived from the dried root or rhizome of Salviae miltiorrhizae BGE., has Tanshinone IIA (TSA) as one of its active ingredients. Recent reports have shown that TSA can inhibit the apoptosis induced by serum withdrawal or ethanol in cultured PC12 cells. However, whether TSA has any neuroprotective effect remains unknown. In this study, we investigated the effects of TSA on cerebral apoptosis induced by middle cerebral artery occlusion (MCAO) in which cerebral ischemia had been induced 2 h earlier. Twenty-four hours after reperfusion, the rats were assessed for infarct volume etc. Intraperitoneal administration of 25 and 40 mg/kg TSA 10 min after MCAO significantly diminished infarct volume and brain water content and improved neurological deficits in a dose-dependent manner. The 25 mg/kg dosage was more effective. Treatment with 25 mg/kg TSA significantly improved symptoms and reduce infarct volume at different points in time, of which 10 min after MCAO was the most significant. Nissl-staining and HE-staining of the 25 mg/kg TSA group were more appreciable in terms of improvement relative to the vehicle group in the infarct core. TSA of dosage 25 mg/kg significantly decreased the expression of cleaved caspase-3 protein and increased the expression of B-cell lymphoma 2 (bcl-2) protein in the ischemic cortex. Fewer terminal deoxyribonucleotidyl transferase-mediated deoxyuridine triphosphate biotin nick-end labeling (TUNEL)-positive cells were found in the penumbra of the treated group, but they were significantly more common in the vehicle group. We here conclude that the neuroprotective effects of TSA against focal cerebral ischemic/reperfusion injury are likely to be related to the attenuation of apoptosis.     

Activation of metabotropic receptors has a neuroprotective effect in a rodent model of focal ischaemia.

The role of the glutamate 'metabotropic' receptor was investigated in an experimental model of focal ischaemia-induced neurodegeneration. The metabotropic agonist, trans-1-amino cyclopentane-1,3-dicarboxylic acid (t-ACPD, 20 mg/kg i.p.), was administered to mice immediately after middle cerebral artery occlusion (MCAO), which causes cerebral infarct. Seven days after MCAO, the mean infarct volume value of the t-ACPD-treated group (mean +/- S.E. = 4.57 +/- 0.73 mm3) was significantly reduced, by 34.3%, compared to the vehicle-treated group (mean +/- S.E. = 6.95 +/- 0.59 mm3, P less than 0.01). This suggests that metabotropic receptor activation in the adult brain reduces excitotoxicity.     

新型神经保护剂TQ0701-2对大鼠脑缺血再灌注损伤的保护作用

目的：研究新型神经保护剂TQ0701-2对大鼠脑缺血再灌注损伤的保护作用。方法：将120只雄性SD大鼠随机分为假手术组、模型组、依达拉奉组（3.0mg/kg）以及TQ0701-2高剂量组（6.0mg/kg）、中剂量组（3.0mg/kg）、低剂量组（1.5mg/kg）。假手术组仅进行手术而不造成缺血状态,其余各组均采用Longa线栓法制备大鼠MCAO模型,在缺血2h后进行再灌注。TQ0701-2三个剂量组和依达拉奉组分别在缺血前30min以及再灌注0、2h尾静脉注射TQ0701-2和依达拉奉,假手术组和模型组则给予等量的生理盐水。再灌注24h后观察大鼠神经功能损伤症状、脑组织梗死率以及病理组织学的改变。结果：模型组大鼠神经功能损伤严重,脑组织梗死率也明显增高（P〈0.01vs假手术组）。与依达拉奉的保护作用相同,TQ0701-2高中低三个剂量均能显著降低MCAO大鼠的神经功能评分和脑组织梗死率（P〈0.01vs模型组）,并且三个剂量的改善作用是随着浓度增大而增强的,具有剂量相关性。另外,TQ0701-2对大鼠脑缺血再灌注所致的神经元变性、坏死也有一定的保护作用。结论：研究表明,依达拉奉衍生物TQ0701-2对大鼠的脑缺血再灌注损伤有明显的神经保护作用。     

Neuroprotective effects of an AMPA receptor antagonist YM872 in a rat transient middle cerebral artery occlusion model

The neuroprotective effects of YM872 ([2,3-dioxo-7-(1H-imidazol-1-yl)6-nitro-1,2,3,4-tetrahydro-1-quinoxal inyl]acetic acid monohydrate), a novel alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) receptor antagonist with high water solubility, were examined in rats with transient middle cerebral artery (MCA) occlusion. The right MCA of male SD rats was occluded for 3 h using the intraluminal suture occlusion method. YM872 significantly reduced the infarct volume 24 hours after occlusion, at dosages of 20 and 40 mg/kg/h (iv infusion) when given for 4 h immediately after occlusion. Furthermore, delayed administration of YM872 (20 mg/kg/h iv infusion for 4 h, starting 2 or 3 h after the occlusion) also reduced the infarct volume and the neurological deficits measured at 24 h. Additionally, the therapeutic efficacy of YM872 persisted for at least seven days after MCA occlusion in animals treated with YM872 for 4 h starting 2 h after MCA occlusion. These data demonstrate that AMPA receptors contribute to the development of neuronal damage after reperfusion as well as during ischemia in the focal ischemia models and that the acute effect of the blockade of AMPA receptors persists over a long time period. YM872 shows promise as an effective treatment for patients suffering from acute stroke.