Neuroprotective effects of hydroxyethylpuerarin against focal cerebral ischemia-reperfusion in rats

Our present study was performed to investigate whether hydroxyethylpuerarin (HEP) has a neuroprotective effect on brain injury after focal cerebral ischemia/reperfusion by middle cerebral artery occlusion (MCAO) in adult male Wistar rats. Animals were subjected to one hour of middle cerebral artery occlusion and 48 hours of reperfusion with the pretreatment of drugs (HEP 15, 30, 60 mg/ kg or nimodipine 0.4 mg/kg i.v.) or vehicle. The behavioral tests were used to evaluate the damage to central nervous system. The percentage of brain infarct area was assessed in the brain slices stained with 2% solution of 2, 3, 5-triphenyl tetrazolium chloride (TTC). The pathologic histological changes were observed by H&E staining and the occurrence of apoptosis was determined by flow cytometry. The results showed that pretreatment with HEP at doses of 15, 30, 60 mg/kg exhibited significant neuroprotective effects on rats against focal cerebral ischemia-reperfusion injury by markedly decreasing neurological deficit scores and the percentage of infarct area, reducing necrosis and apoptosis of neurons. All these findings suggest that HEP might provide neuroprotection against focal cerebral ischemia/reperfusion injury probably through its antioxidant and anti-inflammatory property.     

Astragaloside IV protects against focal cerebral ischemia/reperfusion injury correlating to suppression of neutrophils adhesion-related molecules

Inflammation injury plays a key role in the process of cerebral injury induced by ischemia/reperfusion (I/R). Thus, we studied the potential of astragaloside IV, one of the major and active components of the astragalus membranaceous, to protect rat against cerebral inflammation injury elicited by focal cerebral ischemia and reperfusion and related protective mechanisms. The rat model was induced by intraluminal occlusion of the right middle cerebral artery with reperfusion. Animals received astragaloside IV (10 or 20 mg/kg) injections when reperfusion was began to. Neurobehavioral evaluation and infarct assessment were studied. Myeloperoxidase (MPO) and tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) were measured by enzyme-linked immunosorbent assay (ELISA). The rates of CD11b/CD18-positive neutrophils were analyzed via flow cytometry. Intercellular adhesion molecule-1 (ICAM-1) and nuclear factor κB (NF-κB) were measured by immunohistochemistry and Western blot. Astragaloside IV improved neurological outcome and reduced infarct volume at 24 h after reperfusion. The protective effect was achieved by preventing neutrophils accumulation in the brain parenchyma demonstrated by significantly reducing the concentration of MPO in brain tissue. Astragaloside IV exerts the protection through remarkably decreasing the percentage of CD11b/CD18-positive neutrophils and down-regulating the expression of intercellular adhesion molecule-1 (ICAM-1), which is partly achieved by strongly attenuating the production of TNF-α and IL-1β and inhibiting level of nuclear factor-κB (NF-κB). We propose an anti-inflammatory mechanism evoked by astragaloside IV by suppression of neutrophils adhesion-related molecules, which exerts neuroprotection against I/R injury.     

Overexpression of HSPA12B protects against cerebral ischemia/reperfusion injury via a PI3K/Akt-dependent mechanism

Background and purpose: HSPA12B is a newly discovered member of the Hsp70 family proteins. This study investigated the effects of HSPA12B on focal cerebral ischemia/reperfusion (I/R) injury in mice. Methods: Transgenic mice overexpressing human HSPA12B (Tg) and wild-type littermates (WT) were subjected to 60 min of middle cerebral artery occlusion to induce ischemia and followed by reperfusion (I/R). Neurological deficits, infarct volumes and neuronal death were examined at 6 and 24 hrs after reperfusion. Blood–brain-barrier (BBB) integrity and activated cellular signaling were examined at 3 hrs after reperfusion. Results: After cerebral I/R, Tg mice exhibited improvement in neurological deficits and decrease in infarct volumes, when compared with WT I/R mice. BBB integrity was significantly preserved in Tg mice following cerebral I/R. Tg mice also showed significant decreases in cell injury and apoptosis in the ischemic hemispheres. We observed that overexpression of HSPA12B activated PI3K/Akt signaling and suppressed JNK and p38 activation following cerebral I/R. Importantly, pharmacological inhibition of PI3K/Akt signaling abrogated the protection against cerebral I/R injury in Tg mice. Conclusions: The results demonstrate that HSPA12B protects the brains from focal cerebral I/R injury. The protective effect of HSPA12B is mediated though a PI3K/Akt-dependent mechanism. Our results suggest that HSPA12B may have a therapeutic potential against ischemic stroke.     

Vitexin protects brain against ischemia/reperfusion injury via modulating mitogen-activated protein kinase and apoptosis signaling in mice

Vitexin is a major bioactive flavonoid compound derived from the dried leaf of hawthorn (Crataegus pinnatifida), a widely used conventional folk medicine in China. Recent studies have shown that vitexin presents neuroprotective effects in vitro. Whether this protective effect applies to the cerebral ischemia/reperfusion (I/R) injury remains elusive. In the present study, we examined the potential neuroprotective effect of vitexin against cerebral I/R injury and underlying mechanisms. A focal cerebral I/R model in male Kunming mice was induced by middle cerebral artery occlusion (MCAO) for 2 h followed by reperfusion for 22 h. The neurological function and infarct volume were assessed by using Long's five-point scale system and triphenyl-tetrazolium chloride (TTC) staining technique, respectively. Neuronal damage was evaluated by histological staining. Extracellular signal-regulated kinases 1/2 (ERK1/2), c-Jun N-terminal kinases (JNK) and p38 phosphorylation, and apoptosis were measured via Western blot at 24 h after reperfusion. As a result, systemic vitexin treatment significantly reduced neurological deficit, cerebral infarct volume and neuronal damage when compared with the I/R group. Western blot analyses revealed that vitexin markedly upregulated p-ERK1/2 and downregulated p-JNK and p-p38. Meanwhile, vitexin increased Bcl-2 expression and suppressed the overexpression of Bax in the I/R injury mice. In conclusion, the results indicate that vitexin protects brain against cerebral I/R injury, and this effect may be regulated by mitogen-activated protein kinase (MAPK) and apoptosis signaling pathways.     

Effects of intracerebroventricular injection of delta-opioid receptor agonist TAN-67 or antagonist naltrindole on acute cerebral ischemia in rat

This work was performed to determine the role of delta-opioid receptor (DOR) in protection against acute ischemia/reperfusion injury. Transient (1 h) focal cerebral ischemia was induced by middle cerebral artery occlusion (MCAO). DOR agonist TAN-67 (30 nmol, 60 nmol, 200 nmol), DOR antagonist naltrindole (20 nmol, 50 nmol, 100 nmol) or artificial cerebral spinal fluid (aCSF) was injected respectively into the lateral cerebroventricle of the rat 30 min before the induction of brain ischemia. Neurological deficits were assessed by the five-grade system (Longa's methods). The brain infarct was measured by cresyl violet (CV) staining and infarct volume was analyzed by an image processing and analysis system. The expression of DOR was detected by Western blot. The results showed that 60 nmol TAN-67 significantly reduced the infarct volume (P<0.05), attenuated neurological deficits (P<0.05) and tended to increase the expression of about 60 kDa DOR protein (P>0.05), while 100 nmol naltrindole aggravated ischemic damage and decreased about 60 kDa DOR protein expression (P<0.05). These results suggest that DOR activation protects the brain against acute ischemia/reperfusion injury in rat.     

蜂胶黄酮对大鼠脑缺血再灌注损伤后IL-1β、IL-6和TNF-α含量的影响

目的探讨蜂胶黄酮对脑缺血再灌注损伤的保护作用。方法采用大鼠大脑中动脉栓塞模型（MCAO）,研究蜂胶黄酮对脑缺血再灌注脑梗死体积和行为学评分的影响,对脑组织内IL-1β、IL-6和TNF-α含量的影响。结果蜂胶黄酮能够减少MCAO脑梗死体积和行为学评分,降低脑组织中IL-1β、IL-6和TNF-α的含量（P〈0．05）。结论蜂胶黄酮对大鼠脑缺血再灌注损伤有一定保护作用,其作用机制与降低脑组织中IL-1β、IL-6和TNF-α含量有关。     

Neuroprotective effect of curcumin in middle cerebral artery occlusion induced focal cerebral ischemia in rats

Free radical induced neuronal damage is implicated in cerebral ischemia reperfusion (IR) injury and antioxidants are reported to have neuroprotective activity. Several in vitro and in vivo studies have proved the antioxidant potential of curcumin and its metabolites. Hence, in the present study the neuroprotective potential of curcumin was investigated in middle cerebral artery occlusion (MCAO) induced focal cerebral IR injury. 2 h of MCAO and 22 h of reperfusion resulted in the infarct volume of 210.39 +/- 31.25 mm3. Administration of curcumin 100 and 300 mg/kg, i.p. 30 min. after MCAO produced 37.23 +/- 5.10% and 46.39 +/- 10.23% (p < 0.05) reduction in infarct volume, respectively. Ischemia induced cerebral edema was reduced in a dose dependent manner. Curcumin at 300 mg/kg, i.p. produced 50.96 +/- 6.04% reduction in edema (p < 0.05) volume. Increase in lipid peroxidation after MCAO in ipsilateral and contralateral hemisphere of brain was observed, which was reduced by curcumin (300 mg/kg, i.p.)-treatment. Decrease in superoxide dismutase and glutathione peroxidase activity was observed in ipsilateral hemisphere of MCAO animal. Curcumin-treatment (300 mg/kg, i.p.) prevented IR injury mediated fall in glutathione peroxide activity. Peroxynitrite measured using rhodamine123 fluorescence and anti-nitrotyrosine immunofluorescence indicated increased peroxynitrite formation after IR insult. Curcumin-treatment reduced peroxynitrite formation and hence the extent of tyrosine nitration in the cytosolic proteins. These results suggest the neuroprotective potential of curcumin in cerebral ischemia and is mediated through its antioxidant activity.     

Nicotine-Induced Neuroprotection Against Ischemic Injury Involves Activation of Endocannabinoid System in Rats

Nicotine has been reported to exert certain protective effect in the Parkinson’s and Alzheimer’s diseases. Whether it has a similar action in focal cerebral ischemia was unclear. In the present study, rats received either an injection of (?)-nicotine hydrogen tartrate salt (1.2 mg/kg, i.p.) or the vehicle 2 h before the 120 min middle cerebral artery occlusion. Neurological deficits and histological injury were assessed at 24 h after reperfusion. The content of endocannabinoids and the expression of cannabinoid receptor CB1 in brain tissues were determined at different time points after nicotine administration. Results showed that nicotine administration ameliorated neurological deficits and reduced infarct volume induced by cerebral ischemia in the rats. The neuroprotective effect was partially reversed by CB1 blockage. The content of the endocannabinoids N-arachidonylethanolamine and 2-arachidonoylglycerol, as well as the expression of cannabinoid receptor CB1 were up-regulated in brain tissues after nicotine delivery. These results suggest that endogenous cannabinoid system is involved in the nicotine-induced neuroprotection against transient focal cerebral ischemia.     

PI3K/Akt 通路在电针预处理诱导脑缺血耐受中的机制研究

目的:通过观察电针预处理对磷脂酰肌醇3激酶/蛋白质丝氨酸苏氨酸激酶(PI3K/Akt)通路的变化以及该通路抑制剂对电针预处理的脑保护的影响,探讨电针预处理诱导脑缺血耐受的可能机制。方法:线栓法单侧阻断大脑中动脉120min,再灌注24h制备大鼠大脑局灶性缺血再灌注(I/R)模型;Western Blot检测Akt磷酸化水平的变化;侧脑室注射PI3K/Akt通路抑制剂LY294002;神经行为学评分(Garcia标准)及TTC染色检测脑梗死体积比评价脑损伤程度。结果:电针预处理使大鼠神经行为学评分增高,脑梗死体积比降低(P<0.05);可上调Akt磷酸化水平,I/R2h达高峰(P<0.05)。侧脑室注射PI3K/Akt抑制剂LY294002,拮抗电针预处理的脑保护作用(P<0.05)。结论:电针预处理增加Ak(tSer473)磷酸化水平,在缺血再灌注早期上调PI3K/Akt通路可能是诱导大鼠脑缺血耐受的产生的主要机制。     

Atorvastatin protects against cerebral infarction via inhibition of NADPH oxidase-derived superoxide in ischemic stroke

Statins have recently been shown to exert neuronal protection in ischemic stroke. Reactive oxygen species, specifically superoxide formed during the early phase of reperfusion, augment neuronal injury. NADPH oxidase is a key enzyme for superoxide production. The present study tested the hypothesis that atorvastatin protects against cerebral infarction via inhibition of NADPH oxidase-derived superoxide in transient focal ischemia. Transient focal ischemia was created in halothane-anesthetized adult male Sprague-Dawley rats (250-300 g) by middle cerebral artery occlusion (MCAO). Atorvastatin (Lipitor, 10 mg/kg sc) was administered three times before MCAO. Infarct volume was measured by triphenyltetrazolium chloride staining. NADPH oxidase enzymatic activity and superoxide levels were quantified in the ischemic core and penumbral regions by lucigenin (5 microM)-enhanced chemiluminescence. Expression of NADPH oxidase membrane subunit gp91(phox) and membrane-translocated subunit p47(phox) and small GTPase Rac-1 was analyzed by Western blot. NADPH oxidase activity and superoxide levels increased after reperfusion and peaked within 2 h of reperfusion in the penumbra, but not in the ischemic core, in MCAO rats. Atorvastatin pretreatment prevented these increases, blunted expression of membrane subunit gp91(phox), and prevented translocation of cytoplasmic subunit p47(phox) to the membrane in the penumbra 2 h after reperfusion. Consequently, cerebral infarct volume was significantly reduced in atorvastatin-treated compared with nontreated MCAO rats 24 h after reperfusion. These results indicate that atorvastatin protects against cerebral infarction via inhibition of NADPH oxidase-derived superoxide in transient focal ischemia.     

NXY-059, a nitrone with free radical trapping properties inhibits release of cytochrome c after focal cerebral ischemia.

Recent studies have demonstrated that disodium 2,4-disulfophenyl-N-tert-butylnitrone (NXY-059), a novel nitrone with free radical trapping properties, has a considerable neuroprotective effect against cerebral ischemic injury. The mechanisms of its action have not been fully defined. In order to evaluate whether NXY-059 exerts its protective effects by inhibiting the release of cytochrome c, a key initiator of programmed cell death pathway, we have studied the effects of NXY-059 on reducing infarct volume and on inhibiting cytochrome c release from the mitochondria after transient focal cerebral ischemia. Wistar rats were subjected to 2 hr of middle cerebral artery occlusion and perfusion-fixed after 4, 6, 12, and 24 hr of reperfusion. NXY-059 (30 mg/kg) was i.v. injected 1 hr after reperfusion and followed immediately by 30 mg/kg/hr continuous i.v. infusion for the entire reperfusion period. The results showed that NXY-059 reduced infarct volume from 37.2% to 12.5% (p<0.0001). Immunocytochemistry demonstrated that the release of cytochrome c increased at 6 hr, peaked at 12 and 24 hr of reperfusion. NXY-059 treatment prevented ischemia-induced cytochrome c release. NXY-059 may reduce ischemic brain damage through suppressing the cell death pathway that is initiated by cytochrome c release.     

Involvement of free radicals in cerebral vascular reperfusion injury evaluated in a transient focal cerebral ischemia model of rat

Free radicals have been suggested to be largely involved in the genesis of ischemic brain damage, as shown in the protective effects of alpha-phenyl-N-tert-butyl nitrone (PBN), a spin trapping agent, against ischemic cerebral injury. In the present study, the effects of PBN as well as MCI-186, a newly-developed free radical scavenger, and oxypurinol, an inhibitor of xanthine oxidase, were evaluated in a rat transient middle cerebral aretery (MCA) occlusion model to clarify the possible role of free radicals in the reperfusion injury of brain. The volume of cerebral infarction, induced by 2-h occlusion and subsequent 2-h reperfusion of MCA in Fisher-344 rats, was evaluated. The administration of PBN (100 mg/kg) and MCI-186 (100 mg/kg) just before reperfusion of MCA significantly reduced the infarction volume. In contrast, oxypurinol (100 mg/kg) failed to show any preventive effect on the infarction. These results suggest that free radical formation is involved in the cerebral damage induced by ischemia-reperfusion of MCA, and that hydroxyl radical is responsible for the reperfusion injury after transient focal brain ischemia. It is also suggested that xanthine oxidase is not a major source of free radicals.     

Biochemical and Molecular Characteristics of the Brain with Developing Cerebral Infarction

1. We review the biochemical and molecular changes in brain with developing cerebral infarction, based on recent findings in experimental focal cerebral ischemia.2. Occlusion of a cerebral artery produces focal ischemia with a gradual decline of blood flow, differentiating a severely ischemic core where infarct develops rapidly and an area peripheral to the core where the blood flow reduction is moderate (called penumbra). Neuronal injury in the penumbra is essentially reversible but only for several hours. The penumbra area tolerates a longer duration of ischemia than the core and may be salvageable by pharmacological agents such as glutamate antagonists or prompt reperfusion.3. Upon reperfusion, brain cells alter their genomic properties so that protein synthesis becomes restricted to a small number of proteins such as stress proteins. Induction of the stress response is considered to be a rescue program to help to mitigate neuronal injury and to endow the cells with resistance to subsequent ischemic stress. The challenge now is to determine how the neuroprotection conferred by prior sublethal ischemia is achieved so that rational strategies can be developed to detect and manipulate gene expression in brain cells vulnerable to ischemia.4. Expansion of infarction may be caused by an apoptotic mechanism. Investigation of apoptosis may also help in designing novel molecular strategies to prevent ischemic cell death.5. Ischemia/reperfusion injury is accompanied by inflammatory reactions induced by neutrophils and monocytes/macrophages infiltrated and accumulated in ischemic areas. When the role of the inflammatory/immune systems in ischemic brain injury is revealed, new therapeutic targets and agents will emerge to complement and synergize with pharmacological intervention directed against glutamate and Ca²⁺ neurotoxicity.     

Delayed activin A administration attenuates tissue death after transient focal cerebral ischemia and is associated with decreased stress-responsive kinase activation

Focal cerebral ischemia and reperfusion initiates complex cellular and molecular interactions that lead to either cell repair or destruction. In earlier work, we found that activin A is an early gene response to cerebral ischemia and supports cortical neuron survival in vitro. In this study, the ability of exogenous activin A to attenuate injury from transient middle cerebral artery occlusion was tested in adult mice. Intracerebroventricular administration of activin A prior to middle cerebral artery occlusion reduced infarct volume apparent 1 day after experimental stroke. A single activin A administration at 6 h following ischemia/reperfusion reduced lesion volumes at 1 and 3 days and led to improved neurobehavior. Moreover, activin A treatment spared neurons within the ischemic hemisphere and led to a concomitant reduction in microglial activation. Activation of the stress-responsive kinases p38 and c- jun N-terminal kinase implicated in neuronal apoptosis after stroke was reduced following activin A treatment. Together these findings suggest that activin A promotes tissue survival after focal cerebral ischemia/reperfusion with an extended therapeutic window.     

厄贝沙坦对局灶脑缺血作用的实验研究

目的：研究1型血管紧张素Ⅱ受体阻滞剂厄贝沙坦对局灶性脑缺血的神经保护作用及其可能的细胞机制。方法：在激光多谱勒脑血流监测仪对局部脑血流的监测下,应用线栓法建立大鼠大脑中动脉阻塞模型。药物经侧脑室内微泵持续灌注雄性正常血压大鼠,术后行神经功能评分,测定梗死体积,并运用免疫组化染色观察活性Caspase-3及其下游多聚ADP-核糖聚合酶（PARP）p85裂解片断的改变,结合TUNEL,比较各组细胞凋亡情况。结果：厄贝沙坦明显改善大鼠的神经功能评分,第7d的梗死体积较对照组减少了42％,用药后缺血区的TUNEL阳性细胞数．荧光标记的活性Caspase-3以及PARP p85裂解片断表达均明显减少。结论：厄贝沙坦可改善局灶脑缺血的神经功能,抑制细胞凋亡可能是其神经保护机制之一。     

mGluR1 antagonist decreases tyrosine phosphorylation of NMDA receptor and attenuates infarct size after transient focal cerebral ischemia

The contribution of metabotropic glutamate receptors to brain injury after in vivo cerebral ischemia remains to be determined. We investigated the effects of the metabotropic glutamate receptor 1 (mGluR1) antagonist LY367385 on brain injury after transient (90 min) middle cerebral artery occlusion in the rat and sought to explore their mechanisms. The intravenous administration of LY367385 (10 mg/kg) reduced the infarct volume at 24 h after the start of reperfusion. As the Gq-coupled mGluR1 receptor is known to activate the PKC/Src family kinase cascade, we focused on changes in the activation and amount of these kinases. Transient focal ischemia increased the amount of activated tyrosine kinase Src and PKC in the post-synaptic density (PSD) at 4 h of reperfusion. The administration of LY367385 attenuated the increases in the amounts of PSD-associated PKCγ and Src after transient focal ischemia. We further investigated phosphorylation of the NMDA receptor, which is a major target of Src family kinases to modulate the function of the receptor. Transient focal ischemia increased the tyrosine phosphorylation of NMDA receptor subunits NR2A and NR2B. Tyrosine phosphorylation of NR2A, but not that of NR2B, in the PSD at 4 h of reperfusion was inhibited by LY367385. These results suggest that the mGluR1 after transient focal ischemia is involved in the activation of Src, which may be linked to the modification of properties of the NMDA receptor and the development of cerebral infarction.     

Calcitonin gene-related peptide prevents blood-brain barrier injury and brain edema induced by focal cerebral ischemia reperfusion

Cerebral ischemia is one of the diseases that most compromise the human species. Therapeutic recovery of blood-brain barrier (BBB) disruption represents a novel promising approach to reduce brain injury after stroke. To determine the effects of calcitonin gene-related peptide (CGRP) on the BBB participate in stroke progression, rat cerebral ischemia reperfusion injury was induced by a 2-hour left transient middle cerebral artery occlusion (MCAO) using an intraluminal filament, followed by 46h of reperfusion. CGRP (1μg/ml) at the dose of 3μg/kg (i.p.) was administered at the beginning of reperfusion. Subsequently, 48h after MCAO, arterial blood pressure, infarct volume, water content, BBB permeability, BBB ultrastructure, levels of aquaporin-4 (AQP4) and its mRNA were evaluated. CGRP could reduce arterial blood pressure (P<0.001), infarct volume (P<0.05), cerebral edema (P<0.01), BBB permeability (P<0.05), AQP4 mRNA expression (P<0.05) and AQP4 protein expression (P<0.01). Furthermore, CGRP treatment improved ultrastructural damage of capillary endothelium cells and decreased the loss of the tight junction observed by transmission electronic microscopy (TEM) after 46h of reperfusion. Our findings show that CGRP significantly reduced postischemic increase of brain edema with a 2-hour therapeutic window in the transient model of focal cerebral ischemia. Moreover, it seems that at least part of the anti-edematous effects of CGRP is due to decrease of BBB disruption by improving ultrastructural damage of capillary endothelium cells, enhancing basal membrane, and inhibiting AQP4 and its mRNA over-expression. The data of the present study provide a new possible approach for acute stroke therapy by administration of CGRP.     

亚低温联合镁剂对脑缺血再灌注大鼠保护作用的研究

目的:rt-PA溶栓为缺血性卒中最有效的治疗方法,脑血流再通后挽救濒临死亡的神经细胞同时,也可能发生更为严重而持久的脑缺血再灌注损伤。本研究探讨联合应用局部亚低温(32-35℃)及硫酸镁对局灶性脑缺血再灌注大鼠的保护作用及其可能机制。方法:通过线栓法建立大鼠大脑中动脉阻塞(MCAO)及再通模型,将50只雄性Wistar大鼠随机分为假手术组、常温组、亚低温组、硫酸镁组、亚低温+硫酸镁组,每组10例,采用Longa神经功能评分、TTC染色、干湿重法、TUNEL技术,检测和比较各组脑缺血再灌注后大鼠的神经功能、脑梗死体积、脑组织含水量及凋亡细胞数。结果:与常温组相比,亚低温组与亚低温+硫酸镁组的梗死体积、神经功能评分、脑组织含水量、凋亡细胞数均明显降低,差异有显著意义(P0.05);而与亚低温组相比,亚低温+硫酸镁组局灶脑缺血大鼠的脑梗死体积、神经功能评分、脑组织含水量、凋亡细胞数均显著减少,差异有显著意义(P0.05)。结论:与单独应用亚低温相比,局部亚低温与硫酸镁联合应用,对局灶性脑缺血再灌注大鼠可发挥更有效的脑保护作用。其机制可能与抑制脑缺血再灌注后凋亡及减轻脑水肿有关。二者联用可能为缺血性卒中患者提供一种减轻溶栓后再灌注损伤的有效脑保护方法。     

Carvacrol, a food-additive, provides neuroprotection on focal cerebral ischemia/reperfusion injury in mice

Carvacrol (CAR), a naturally occurring monoterpenic phenol and food additive, has been shown to have antimicrobials, antitumor, and antidepressant-like activities. A previous study demonstrated that CAR has the ability to protect liver against ischemia/reperfusion injury in rats. In this study, we investigated the protective effects of CAR on cerebral ischemia/reperfusion injury in a middle cerebral artery occlusion mouse model. We found that CAR (50 mg/kg) significantly reduced infarct volume and improved neurological deficits after 75 min of ischemia and 24 h of reperfusion. This neuroprotection was in a dose-dependent manner. Post-treatment with CAR still provided protection on infarct volume when it was administered intraperitoneally at 2 h after reperfusion; however, intracerebroventricular post-treatment reduced infarct volume even when the mice were treated with CAR at 6 h after reperfusion. These findings indicated that CAR has an extended therapeutic window, but delivery strategies may affect the protective effects of CAR. Further, we found that CAR significantly decreased the level of cleaved caspase-3, a marker of apoptosis, suggesting the anti-apoptotic activity of CAR. Finally, our data indicated that CAR treatment increased the level of phosphorylated Akt and the neuroprotection of CAR was reversed by a PI3K inhibitor LY-294002, demonstrating the involvement of the PI3K/Akt pathway in the anti-apoptotic mechanisms of CAR. Due to its safety and wide use in the food industry, CAR is a promising agent to be translated into clinical trials.