Permeability of novel 4′-<Emphasis Type="Italic">N</Emphasis>-substituted (aminomethyl) benzoate-7-substituted nicotinic acid ester derivatives of scutellarein in Caco-2 cells and in an in vitro model of the blood-brain barrier

A series of 4′-N-substituted (aminomethyl) benzoate-7-substituted nicotinic acid ester derivatives of scutellarein was designed and synthesized. Evaluation of physiochemical properties showed that the newly designed compounds had greater chemical stability and aqueous solubility than scutellarin or scutellarein. The permeabilities (P _{app AP to BL}) of compounds 7b and 7e in Caco-2 cells were 5.9-fold and 3.7-fold higher than that of scutellarin, and 3.7-fold and 2.4-fold higher than that of scutellarein. The permeabilities (P _{app AP to BL}) of compounds 7b and 7e in an in vitro model of the blood–brain barrier were 9.7-fold and 5.9-fold higher than that of scutellarin, and 9.2-fold and 5.6-fold higher than that of scutellarein.     

Neuroprotective effects of scutellarin on rat neuronal damage induced by cerebral ischemia/reperfusion

AIM: To investigate the neuroprotective effect and mechanisms of scutellarin, a flavonoid extracted from Erigeron breviscapus Hand Mazz, against neuronal damage following cerebral ischemia/reperfusion. METHODS: Rats were pretreated ig with scutellarin for 7 d and then subjected to cerebral ischemia/reperfusion (I/R) injury induced by a middle cerebral artery occlusion (MCAO). The infarct volume and neurological deficit were determined by TTC staining and Longa's score. The permeability of the blood-brain barrier was evaluated by measurement of the Evans blue (EB) content in the brain with a spectrophotometer. The total NOx content was determined. Nitric oxide synthase (NOS) isoforms (iNOS, eNOS, nNOS) and the key angiogenic molecules, vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF), were detected by Western blotting. RESULTS: Scutellarin significantly reduced infarct volume (P<0.05 or P<0.01), ameliorated the neurological deficit and reduced the permeability of the blood-brain barrier (BBB) (P<0.05). When rats were pretreated with scutellarin (50 or 75 mg/kg), upregulation of eNOS expression and downregulation of VEGF, bFGF, and iNOS expression was observed, whereas scutellarin had no effect on nNOS expression. CONCLUSION: Scutellarin has protective effects for cerebral injury through regulating the expression of NOS isoforms and angiogenic molecules.     

Deficiency of anti-inflammatory cytokine IL-4 leads to neural hyperexcitability and aggravates cerebral ischemia–reperfusion injury

Systematic administration of anti-inflammatory cytokine interleukin 4 (IL-4) has been shown to improve recovery after cerebral ischemic stroke. However, whether IL-4 affects neuronal excitability and how IL-4 improves ischemic injury remain largely unknown. Here we report the neuroprotective role of endogenous IL-4 in focal cerebral ischemia–reperfusion (I/R) injury. In multi-electrode array (MEA) recordings, IL-4 reduces spontaneous firings and network activities of mouse primary cortical neurons. IL-4 mRNA and protein expressions are upregulated after I/R injury. Genetic deletion of Il-4 gene aggravates I/R injury in vivo and exacerbates oxygen-glucose deprivation (OGD) injury in cortical neurons. Conversely, supplemental IL-4 protects Il-4^−/− cortical neurons against OGD injury. Mechanistically, cortical pyramidal and stellate neurons common for ischemic penumbra after I/R injury exhibit intrinsic hyperexcitability and enhanced excitatory synaptic transmissions in Il-4^−/− mice. Furthermore, upregulation of Nav1.1 channel, and downregulations of KCa3.1 channel and α6 subunit of GABA_A receptors are detected in the cortical tissues and primary cortical neurons from Il-4^−/− mice. Taken together, our findings demonstrate that IL-4 deficiency results in neural hyperexcitability and aggravates I/R injury, thus activation of IL-4 signaling may protect the brain against the development of permanent damage and help recover from ischemic injury after stroke.     

Inhibition of intracellular proton-sensitive Ca2+-permeable TRPV3 channels protects against ischemic brain injury

Ischemic brain stroke is pathologically characterized by tissue acidosis, sustained calcium entry and progressive cell death. Previous studies focusing on antagonizing N-methyl-d-aspartate (NMDA) receptors have failed to translate any clinical benefits, suggesting a non-NMDA mechanism involved in the sustained injury after stroke. Here, we report that inhibition of intracellular proton-sensitive Ca²⁺-permeable transient receptor potential vanilloid 3 (TRPV3) channel protects against cerebral ischemia/reperfusion (I/R) injury. TRPV3 expression is upregulated in mice subjected to cerebral I/R injury. Silencing of TRPV3 reduces intrinsic neuronal excitability, excitatory synaptic transmissions, and also attenuates cerebral I/R injury in mouse model of transient middle cerebral artery occlusion (tMCAO). Conversely, overexpressing or re-expressing TRPV3 increases neuronal excitability, excitatory synaptic transmissions and aggravates cerebral I/R injury. Furthermore, specific inhibition of TRPV3 by natural forsythoside B decreases neural excitability and attenuates cerebral I/R injury. Taken together, our findings for the first time reveal a causative role of neuronal TRPV3 channel in progressive cell death after stroke, and blocking overactive TRPV3 channel may provide therapeutic potential for ischemic brain injury.     

Myrtenol improves brain damage and promotes angiogenesis in rats with cerebral infarction by activating the ERK1/2 signalling pathway

ContextCerebral ischaemia/reperfusion (I/R) injury has a high disability and fatality worldwide. Myrtenol has protective effects on myocardial I/R injury through antioxidant and anti-apoptotic effects.ObjectiveThis study investigated the effect of myrtenol on cerebral ischaemia/reperfusion (I/R) injury and the underlying mechanism.Materials and methodsCerebral I/R injury was induced in adult Sprague-Dawley rats by middle cerebral artery occlusion (MCAO) for 90 min. MCAO rats were treated with or without myrtenol (10, 30, or 50 mg/kg/day) or/and U0126 (10 μL) intraperitoneally for 7 days.ResultsIn the present study, myrtenol had no toxicity at concentrations up to 1.3 g/kg. Myrtenol treatment improved neurological function of MCAO rats, with significantly (p < 0.05) improved neurological deficits (4.31 ± 1.29 vs. 0.00) and reduced brain edoema (78.95 ± 2.27% vs. 85.48 ± 1.24%). Myrtenol extenuated brain tissue injury and neuronal apoptosis, with increased Bcl-2 expression (0.48-fold) and decreased Bax expression (2.02-fold) and caspase-3 activity (1.36-fold). Myrtenol promoted angiogenesis in the brain tissues of MCAO rats, which was reflected by increased VEGF (0.86-fold) and FGF2 (0.51-fold). Myrtenol promoted the phosphorylation of MEK1/2 (0.80-fold) and ERK1/2 (0.97-fold) in MCAO rats. U0126, the inhibitor of ERK1/2 pathway, reversed the protective effects of myrtenol on brain tissue damage and angiogenesis in MCAO rats.Discussion and conclusionsMyrtenol reduced brain damage and angiogenesis through activating the ERK1/2 signalling pathway, which may provide a novel alternative strategy for preventing cerebral I/R injury. Further in vitro work detailing its mechanism-of-action for improving ischaemic cerebral infarction is needed.     

灯盏乙素对缺氧缺血性新生大鼠脑缺氧诱导因子-1α和水通道蛋白9表达水平的影响

目的：研究灯盏乙素对缺氧缺血性脑损伤（HIBD）新生大鼠脑缺氧诱导因子-1α（HIF-1α）和水通道蛋白9（APQ9）表达水平的影响。方法：建立HIBD新生大鼠模型，将新生7日龄SD大鼠随机分为假手术组（sham组）、缺氧缺血组（HIBD组）、灯盏乙素高、中和低剂量组、地塞米松阳性对照组。于缺氧缺血7 d后，观察大鼠体质量增长率，脑组织HE染色观察脑组织病理改变，测定脑含水量，免疫荧光法检测脑HIF-1α蛋白表达，逆转录-多聚酶链反应（RT-PCR）法检测脑HIF-1α、APQ9mRNA表达，ELISA法检测脑caspase-3活性。结果：灯盏乙素能显著升高HIBD大鼠体质量增长率，降低脑组织含水量，抑制脑组织HIF-1α和AQP9mRNA表达，降低脑caspase-3活性。结论：灯盏乙素可减轻HIBD大鼠脑组织水肿，降低HIF-1α和AQP9表达，抑制神经细胞凋亡，发挥脑保护作用。     

Neuroprotective effect of gadolinium: a stretch-activated calcium channel blocker in mouse model of ischemia–reperfusion injury

The present study was designed to investigate the potential of gadolinium, a stretch-activated calcium channel blocker in ischemic reperfusion (I/R)-induced brain injury in mice. Bilateral carotid artery occlusion of 12 min followed by reperfusion for 24 h was given to induce cerebral injury in male Swiss mice. Cerebral infarct size was measured using triphenyltetrazolium chloride staining. Memory was assessed using Morris water maze test and motor incoordination was evaluated using rota-rod, lateral push, and inclined beam walking tests. In addition, total calcium, thiobarbituric acid reactive substance (TBARS), reduced glutathione (GSH), and acetylcholinesterase (AChE) activity were also estimated in brain tissue. I/R injury produced a significant increase in cerebral infarct size. A significant loss of memory along with impairment of motor performance was also noted. Furthermore, I/R injury also produced a significant increase in levels of TBARS, total calcium, AChE activity, and a decrease in GSH levels. Pretreatment of gadolinium significantly attenuated I/R-induced infarct size, behavioral and biochemical changes. On the basis of the present findings, we can suggest that opening of stretch-activated calcium channel may play a critical role in ischemic reperfusion-induced brain injury and that gadolinium has neuroprotective potential in I/R-induced injury.     

Ribonuclease attenuates retinal ischemia reperfusion injury through inhibition of inflammatory response and apoptosis in mice

The present study was aimed to reveal the function of extracellular RNAs (exRNAs) in retinal ischemia reperfusion (I/R) injury, and evaluate whether RNase administration can effectively reduce I/R injury. A retinal I/R injury C57BL/6J wild-type mice model was established by elevating intraocular pressure for 1 h. All mice received 3 doses of RNase or the same dose of normal saline at different time points. After 7 days of reperfusion, retinal damage was quantified by counting retinal ganglion cells and measuring retinal layer thickness. The apoptotic retinal cells were detected by the TUNEL experiment, and the expressions of caspase-3, proinflammatory cytokines in retinal tissues, and glial fibrillary acidic protein (GFAP) protein and mRNA were detected to determine the underlying mechanism. It was found that RNase administration (1) reduced the significant loss of retinal morphology caused by I/R injury; (2) down-regulated the expression of NF-κBp65, IL-6 and GFAP relative to the I/R mice; (3) decreased the apoptosis of retinal cells and the levels of caspase-3; (4) attenuated exRNAs levels in retinal tissues on day 7 after retinal I/R. In short, increased exRNAs may contribute to retinal I/R damages in mice, and RNase therapy can effectively attenuate retinal damage by reducing inflammatory response and apoptosis.     

刺芒柄花素对脑缺血再灌注损伤大鼠的保护作用及其机制研究

目的 研究刺芒柄花素（formoononetin,FOR）对脑缺血再灌注损伤（cerebral ischemia-reperfusion injury,I/R）大鼠的保护作用,并探讨其可能的机制。方法 SD大鼠50只,♂,分为假手术组、I/R组、FOR高、中、低剂量组（100,50,20 mg·kg^-1）。连续灌胃给药7 d后,除假手术组外均采用MCAO法造成大鼠脑缺血模型,2 h后拔出线栓,再灌注24 h后进行神经功能评分;跳台法检测大鼠学习记忆能力;HE染色法观测脑组织病理形态;ELISA法检测血清中NO表达及NOS活性水平;Western blot法检测脑组织中caspase-3、Bcl-2和Bax蛋白的表达。结果 与I/R组相比,FOR高、中、低剂量组能显著降低大鼠神经功能评分（P<0.01）、提高大鼠学习记忆能力（P<0.05或P<0.01）、改善脑组织形态、降低血清中NO表达水平及NOS活性（P<0.01）、降低caspase-3蛋白和Bax蛋白的表达水平并提高Bcl-2的表达水平（P<0.01）。结论 刺芒柄花素对I/R大鼠具有一定的保护作用,其机制可能与抗氧化应激和抗凋亡有关。     

Neuroprotective effect of liquiritin against focal cerebral ischemia/reperfusion in mice via its antioxidant and antiapoptosis properties

Our present study was conducted to investigate whether liquiritin (7-hydroxy-2-[4-[3,4,5-trihydroxy-6-(hydroxymethyl) oxan-2-yl] oxyphenyl]-chroman-4-one, 1), an active component of Glycyrrhiza uralensis Fisch., exerts a neuroprotective effect against focal cerebral ischemia/reperfusion (I/R) in male Institute of Cancer Research (ICR) mice. On the establishment of mice with middle cerebral artery occlusion (MCAO) for 2 h and reperfusion for 22 h, liquiritin at the doses of 40, 20, and 10 mg/kg was administered before MCAO once a day intragastrically for a subsequent 3 days. Neurological deficits and infarct volume were measured, respectively. The levels of malondialdehyde (MDA) and carbonyl, activities of superoxide anion (SOD), catalase (CAT) and glutathion peroxidase (GSH-Px) and reduced glutathione/oxidized disulfide (GSH/GSSG) ratio in brain were estimated spectrophotometrically. 8-Hydroxy-2′-deoxyguanosine (8-OHdG) and terminal deoxynucleotidyl transferase-mediated DuTP-biotin nick end labeling (TUNEL)-positive cells were detected by immunohistochemical analysis. Our results showed that the neurological deficits, infarct volume, and the levels of MDA and carbonyl decreased, the ratio of GSH/GSSG and the activities of SOD, CAT, and GSH-Px were compensatorily up-regulated, and 8-OHdG and TUNEL-positive cells decreased after 22 h of reperfusion in liquiritin-treated groups. These findings suggest that liquiritin might be a potential agent against cerebral I/R injury in mice by its antioxidant and antiapoptosis properties.     

大鼠高血糖－局灶性脑缺血再灌注损伤模型建立的初步研究

目的:建立快速、稳定的大鼠高血糖-局灶性脑缺血再灌注损伤(I/R)模型,探讨将其用于脑缺血再灌注损伤相关研究的可行性.方法:24只大鼠随机等分为4组,分别为正常血糖和高血糖下假手术组(NG-sham,HG-sham),正常血糖和高血糖下脑缺血再灌注损伤组(NG-FCIR, HG-FCIR).术前1 h腹腔注射10%右旋葡萄糖制备高血糖大鼠;采用线栓法阻断大脑中动脉(MCAO)建立I/R模型,脑缺血1 h再灌注3 h.测定各组注射葡萄糖前、缺血开始和再灌注3 h后的血糖;TTC染色比较各组脑组织水肿程度和脑梗死面积;比较各组脑组织乳酸脱氢酶活性、总NOS和iNOS、SOD酶活性,以及NO、MDA含量.结果:与对照组相比,缺血前注射葡萄糖的各组血糖明显升高(P<0.01),并且持续至再灌注3h(P<0.01).与NG-FCIR组相比,HG-FCIR组的脑组织水肿程度增加、脑梗死面积明显增大(P<0.05),脑组织乳酸脱氢酶、总NOS、iNOS活性增加(P<0.05),SOD酶活性明显降低(P<0.05),NO、MDA含量明显增多(P<0.05).结论:术前1 h腹腔注射右旋葡萄糖(2g·kg-1)可诱导大鼠高血糖状态,加速、加重MCAO引起的局灶性脑缺血再灌注损伤.采用高血糖模型,缺血1 h、再灌注3 h时即可用于ROS、NO等相关的药物疗效或机制研究,可显著缩短观察时间.     

Lettuce glycoside B ameliorates cerebral ischemia reperfusion injury by increasing nerve growth factor and neurotrophin-3 expression of cerebral cortex in rats

Aims:

The aim of the study was to investigate the effects of LGB on cerebral ischemia-reperfusion (I/R) injury in rats and the mechanisms of action of LGB.

Materials and Methods:

The study involved extracting LGB from P. laciniata, exploring affects of LGB on brain ischemia and action mechanism at the molecular level. The cerebral ischemia reperfusion injury of middle cerebral artery occlusion was established. We measured brain histopathology and brain infarct rate to evaluate the effects of LGB on brain ischemia injury. The expressions of nerve growth factor (NGF) and neurotrophin-3 (NT-3) were also measured to investigate the mechanisms of action by the real-time polymerase chain reaction and immunohistochemistry.

Statistical analysis:

All results were mentioned as mean ± standard deviation. One-way analysis of variance was used to determine statistically significant differences among the groups. Values of P < 0.05 were considered to be statistically significant.

Results:

Intraperitoneal injection of LGB at the dose of 12, 24, and 48 mg/kg after brain ischemia injury remarkably ameliorated the morphology of neurons and brain infarct rate (P < 0.05, P < 0.01). LGB significantly increased NGF and NT-3 mRNA (messenger RNA) and both protein expression in cerebral cortex at the 24 and 72 h after drug administration (P < 0.05, P < 0.01).

Conclusions:

LGB has a neuroprotective effect in cerebral I/R injury and this effect might be attributed to its upregulation of NGF and NT-3 expression ability in the brain cortex during the latter phase of brain ischemia.KEY WORDS: Cerebral I/R injury, gene, lettuce glycoside B, LGB, neuroprotective effect, P. laciniata, protein     

补阳还五汤联合依达拉奉对脑缺血再灌注后神经细胞凋亡及Bcl-2和Bax表达的影响

目的 研究补阳还五汤联合依达拉奉对小鼠脑缺血再灌注损伤后神经细胞凋亡及凋亡相关蛋白表达的影响。方法 60 只小鼠随机分假手术组（sham）,模型组（I/R）,补阳还五汤组（BYHWD）,依达拉奉组（ED）,补阳还五汤+依达拉奉组（BYHWD+ED）,每组再分2个亚组：1 d组和7 d 组。采用改良线栓法制作小鼠大脑中动脉缺血再灌注模型,分别给药。TUNEL法观察神经细胞凋亡率;进一步Western bolt检测大脑皮质缺血区bcl-2 和 bax的蛋白的定量表达。结果 补阳还五汤+依达拉奉组较其他组能更明显地降低神经细胞凋亡指数(P<0.01),且较其他组可更明显地升高凋亡相关蛋白bcl-2的表达和下调bax的表达 (P<0．05)。结论 补阳还五汤与依达拉奉联用能降低脑缺血再灌注损伤后小鼠脑组织细胞中促凋亡蛋白bax的表达,增加具有神经元保护作用的抑凋亡蛋白bcl-2的表达,从而抑制神经细胞凋亡,加速神经功能的恢复,协同发挥脑保护作用。     

Pharmacological preconditioning by milrinone: Memory preserving and neuroprotective effect in ischemia-reperfusion injury in mice

We tested the neuroprotective effect of milrinone, a phosphodiesterase III inhibitor, in pharmacological preconditioning. Bilateral carotid artery occlusion for 12 min followed by reperfusion for 24 h produced ischemia-reperfusion (I/R) cerebral injury in male Swiss albino mice. Cerebral infarct size was measured using triphenyltetrazolium chloride staining. Memory was assessed using the Morris water maze test, and motor coordination was evaluated using the inclined beam walking test, rota-rod test, and lateral push test. Milrinone (50 μg/kg & 100 μg/kg i.v.) was administered 24 h before surgery in a separate group of animals to induce pharmacological preconditioning. I/R increased cerebral infarct size and impaired memory and motor coordination. Milrinone treatment significantly decreased cerebral infarct size and reversed I/R-induced impairments in memory and motor coordination. This neuroprotective effect was blocked by ruthenium red (3 mg/kg, s.c.), an intracellular ryanodine receptor blocker. These findings indicate that milrinone preconditioning exerts a marked neuroprotective effect on the ischemic brain, putatively due to increased intracellular calcium levels activating calcium-sensitive signal transduction cascades.     

雷公藤甲素通过调节cAMP/PKA/BDNF信号通路促进脑缺血再灌注损伤神经元可塑性

目的 研究雷公藤甲素(triptolide,TP)对脑缺血再灌注(ischemia-reperfution,I/R)损伤大鼠的疗效评价及其发挥效能的机制。方法 大脑中动脉线栓法手术复制大鼠脑I/R损伤模型,治疗组给予TP(0.1,0.2 mg·kg^?1),同时设假手术组。Longa评分法测评鼠神经功能,尼氏染色呈现大鼠缺血侧脑组织神经元形态,免疫荧光法检测缺血侧脑组织中MAP2和Syn的表达水平。Western blotting 法检测cAMP、PKA、BDNF、Syn、PSD-95的表达水平。结果 与模型组比较,TP治疗组神经学评分明显下降(P<0.01或P<0.001),对损伤神经元有保护作用,且TP治疗组cAMP、PKA、BDNF、PSD-95、Syn的表达均显著上调。结论 TP治疗能显著改善I/R损伤,其机制可能与激活cAMP/PKA/BDNF信号通路有关。     

Schisandrin B enhances cerebral mitochondrial antioxidant status and structural integrity, and protects against cerebral ischemia/reperfusion injury in rats

Schisandrin B (Sch B), a dibenzocyclooctadiene derivative isolated from the fruit of Schisandra chinensis, has been shown to enhance mitochondrial antioxidant status in liver, heart and brain tissues in rodents. Whether or not long-term Sch B treatment can protect against oxidative stress-induced cerebral damage remains unclear. In the present study, the effect of long-term Sch B treatment (1-30 mg/kg/dx15) on cerebral ischemia/reperfusion (I/R) injury was examined in rats. Sch B treatment protected against I/R-induced cerebral damage, as evidenced by the significant increase in the percentage of 2,3,5-triphenyl tetrazolium chloride (TTC)-stained tissues in representative brain slices, when compared with the Sch B-untreated and I/R control. The cerebroprotection was associated with an enhancement in cerebral mitochondrial antioxidant status, as assessed by the level/activity of reduced glutathione, alpha-tocopherol and Mn-superoxide dismutase, as well as the improvement/preservation of mitochondrial structural integrity, as assessed by the extents of malondialdehyde production, Ca(2+) loading and cytochrome c release, as well as the sensitivity to Ca(2+)-induced permeability transition, in control and I/R-challenged rats. In conclusion, long-term Sch B treatment could enhance cerebral mitochondrial antioxidant status as well as improve mitochondrial structural integrity, thereby protecting against I/R injury.     

Montelukast, a cysteinyl leukotriene receptor-1 antagonist, attenuates chronic brain injury after focal cerebral ischaemia in mice and rats

Objectives Previously we demonstrated the neuroprotective effect of montelukast, a cysteinyl leukotriene receptor‐1 (CysLT₁) antagonist, on acute brain injury after focal cerebral ischaemia in mice. In this study, we have determined its effect on chronic brain injury after focal cerebral ischaemia in mice and rats. Methods After transient focal cerebral ischaemia was induced by middle cerebral artery occlusion, montelukast was intraperitoneally injected in mice or orally administered to rats for five days. Behavioural dysfunction, brain infarct volume, brain atrophy and neuron loss were determined to evaluate brain lesions. Key findings Montelukast (0.1 mg/kg) attenuated behavioural dysfunction, brain infarct volume, brain atrophy and neuron loss in mice, which was similar to pranlukast, another CysLT₁ receptor antagonist. Oral montelukast (0.5 mg/kg) was effective in rats and was more effective than edaravone, a free radical scavenger. Conclusion Montelukast protected mice and rats against chronic brain injury after focal cerebral ischaemia, supporting the therapeutic potential of CysLT₁ receptor antagonists.     

Propolis ameliorates cerebral injury in focal cerebral ischemia/reperfusion (I/R) rat model via upregulation of TGF-β1

Neuroprotective impact of transforming growth factor β1 (TGF-β1) is increasingly recognized in different brain injuries. Propolis exhibits a broad spectrum of biological and pharmacological properties including neuroprotective action. The objective of the investigation was to explore the involvement of TGF-β1 signaling in the neuroprotective mechanism of propolis in I/R rats. In this study, focal cerebral ischemia model was built by middle cerebral artery occlusion (MCAO) for 2 h followed by reperfusion. The investigation was carried out on 48 rats that were arranged into four groups (n = 12): the sham group, I/R control group, I/R + propolis (50 mg/kg) group and I/R + propolis (100 mg/kg) group. The results revealed that propolis preserved rats against neuronal injury induced by cerebral I/R. It significantly reduced neurological deficit scores and improved motor coordination and locomotor activity in I/R rats. Propolis antagonized the damage induced by cerebral I/R through suppression of malondialdehyde (MDA) and elevation of reduced glutathione (GSH), superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), brain-derived neurotropic factor (BDNF) and dopamine levels in the brain homogenates of I/R rats. Other ameliorations were also observed based on reduction of neurodegeneration and histological alterations in the brain tissues. These results also proposed that the neuroprotective effect of propolis might be related to upregulation of TGF-β1 and suppressed matrix metallopeptidase-9 (MMP9) mRNA expression.     

Garciesculenxanthone B induces PINK1-Parkin-mediated mitophagy and prevents ischemia-reperfusion brain injury in mice

Mitophagy is a selective form of autophagy involving the removal of damaged mitochondria via the autophagy-lysosome pathway.PINK1-Parkin-mediated mitophagy is one of the most important mechanisms in cardiovascular disease,cerebral ischemia-reperfusion(I/R)injury,and neurodegenerative diseases.In this study we conducted an image-based screening in YFP-Parkin HeLa cells to discover new mitophagy regulators from natural xanthone compounds.We found that garciesculenxanthone B(GeB),a new xanthone compound from Garcinia esculenta,induced the formation of YFP-Parkin puncta,a well known mitophagy marker.Furthermore,treatment with GeB dose-dependently promoted the degradation of mitochondrial proteins Tom20,Tim23,and MFN1 in YFP-Parkin HeLa cells and SH-SY5Y cells.We revealed that GeB stabilized PINK1 and triggered Parkin translocation to the impaired mitochondria to induce mitophagy,and these effects were abolished by knockdown of PINK1.Finally,in vivo experiments demonstrated that GeB partially rescued ischemia-reperfusion-induced brain injury in mice.Taken together,our findings demonstrate that the natural compound GeB can promote the PINK1-Parkin-mediated mitophagy pathway,which may be implicated in protection against I/R brain injury.     

Anti-oxidant activity mediated neuroprotective potential of trimetazidine on focal cerebral ischaemia-reperfusion injury in rats

1. The present study was designed to investigate the neuroprotective effect of trimetazidine (TMZ) following focal cerebral ischaemia-reperfusion (I/R) injury in rat forebrain. 2. Cerebral I/R injury was induced in rats by middle cerebral artery occlusion (MCAO) for 2 h, followed by reperfusion for 22 h. Trimetazidine (5 and 25 mg/kg, i.p.) was administered 1 h after induction of MCAO. The effects of TMZ were investigated by measuring neurological deficit, volume of infarct and brain swelling after 22 h reperfusion. Oxidative stress and inflammatory reactivity were assessed by estimating anti-oxidant markers and myeloperoxidase (MPO) activity in brain homogenates. Rectal temperature was measured during the study. The effects of TMZ on blood-brain barrier (BBB) permeability and apoptosis were also investigated in rat brain. Apoptosis was observed by DNA fragmentation studies using agarose gel electrophoresis. 3. Treatment with TMZ significantly (P < 0.01) reduced infarct volume and brain swelling. Superoxide dismutase (SOD) activity was reduced in ipsilateral hemispheres of vehicle (saline)-treated reperfused (RI) animals. Treatment with TMZ significantly restored SOD activity (P < 0.01) and glutathione levels (P < 0.05) after reperfusion compared with RI animals. Lipid peroxidation, MPO activity, BBB permeability and rectal temperature were all significantly (P < 0.01, P < 0.05 and P < 0.001, respectively) reduced in TMZ-treated animals compared with RI animals. 4. These results suggest that TMZ protects the brain against cerebral I/R injury and that this neuroprotective activity could be mediated by its anti-oxidant properties. The reduction in rectal temperature by TMZ treatment may be responsible for maintaining the delicate energy balance during I/R injury in rat brain and could have contributed to the neuroprotective activity of TMZ.