环孢素A对大鼠肺缺血/再灌注损伤中细胞凋亡的影响

目的:探讨线粒体膜通透性转换孔(MPTP)抑制剂——环孢素A(CsA)对大鼠肺常温缺血/再灌注后细胞凋亡的影响。方法:健康SD大鼠30只,随机分为3组(n=10):假手术组、缺血/再灌注组(I/R组)和环孢素A干预组(CsA组)。复制在体肺缺血/再灌注损伤模型。采用原位缺口末端标记(TUNEL)法检测肺组织细胞凋亡,免疫组化技术检测肺组织细胞细胞色素C(CytC)的含量,以及分光光度计测定肺组织细胞caspase-3的活性。结果:I/R组肺组织细胞胞浆CytC的含量、caspase-3活性明显高于假手术组(P0.01),并观察到大量肺组织细胞凋亡的发生。CsA组与I/R组相比,CytC释放明显减少(P0.01),caspase-3活性减弱,细胞凋亡的发生率明显下降(P0.01)。结论:环孢素A可能通过抑制MPTP开放,减少缺血/再灌注后线粒体CytC的释放,从而减少肺组织细胞的凋亡。     

一种用于研究骨骼肌缺血/再灌注损伤的细胞模型

目的:复制L-6TG大鼠肌母细胞缺血/再灌注损伤的细胞模型.方法:将培养的L-6TG大鼠肌母细胞随机分为2组:①正常对照组(C组),②缺血/再灌注组(I/R组),观测了培养上清中乳酸脱氢酶(LDH)、细胞内超氧化物歧化酶(SOD)、黄嘌呤氧化酶(XOD)、Ca2 含量的变化;采用MTT法检测线粒体的功能;在光镜下观察细胞的形态学改变.结果:与对照组相比,L-6TG大鼠肌母细胞IR 4h后培养上清中LDH、细胞内XOD、Ca2 含量明显增加,细胞内SOD及线粒体呼吸功能明显降低,细胞严重受损,明显圆缩,并有脱落现象.结论:应用模拟缺血液和再灌液可成功复制L-6TG大鼠肌母细胞缺血/再灌注损伤的细胞模型.     

甘草查尔酮A对局灶性脑缺血再灌注小鼠Nrf2/HO-1信号通路和神经炎症反应的影响

目的:探讨甘草查尔酮A对局灶性脑缺血再灌注小鼠Nrf2/HO-1信号通路和神经炎症反应的影响。方法:体重23~25 g的雄性C57BL/6小鼠总计96只,随机分为4组(n=24):假手术对照组(Sham组)、脑缺血再灌注组(MCAO组)、溶剂组(Vehicle组)、甘草查尔酮A组(LA组)。采用大脑中动脉栓塞(MCAO)模型致大鼠脑缺血损伤。72 h后行神经功能学评分,2,3,5-三苯基氯化铵(TTC)染色检测脑梗死体积,Western blot法检测脑Nrf2、HO-1、TNF-α、IL-6蛋白表达水平,TUNEL染色法检测凋亡细胞数。结果:与Sham组比较,MCAO组和Vehicle组小鼠神经功能评分明显降低(P0.05),脑梗死体积显著增加(P0.05),而核蛋白Nrf2和胞浆蛋白HO-1蛋白表达水平较低(P0.05),炎症因子IL-6和TNF-α表达水平明显增加(P0.05),脑实质炎性细胞浸润显著增多(P0.05);与MCAO组和Vehicle组比较,LA组小鼠神经功能评分明显增加(P0.05),脑梗死体积显著减少(P0.05),而核蛋白Nrf2和胞浆蛋白HO-1蛋白表达水平更高(P0.05),炎症因子IL-6和TNF-α表达水平明显减少(P0.05),脑实质炎性细胞浸润明显减少(P0.05)。结论:甘草查尔酮A可缓解脑缺血再灌注损伤后出现的神经炎症反应及细胞凋亡,进而减轻神经功能障碍和脑梗死体积,其机制可能与激活Nrf2/HO-1信号通路相关。     

注射用内给氧对缺血再灌注损伤兔肝脏能量代谢的影响

为了探讨注射用内给氧对肝脏缺血再灌注(I/R)损伤肝脏能量代谢的影响,将48只健康新西兰长耳大白兔随机分为4组:假手术组(A组),缺血再灌注组(B组),缺血再灌注 周围静脉注射用内给氧组(C组),缺血再灌注 肝动脉注射内给氧组(D组),每组12只,采用Pringle氏法建立肝脏I/R模型,比较4组大白兔缺血再灌注后1、2、24h肝组织内三磷酸腺苷(ATP)、二磷酸腺苷(ADP)、一磷酸腺苷(AMP)含量、肝脏的细胞能荷(EC)及肝组织形态学的变化.结果表明,与A组比较,8、C、D三组肝功能损害重,肝组织ATP含量,能荷值(EC)降低(P<0.05);肝组织病理学改变明显(P<0.05),B组以上各项指标差异更为显著,与B组比较,C、D二组肝组织ATP含量,能荷值(EC)高(P<0.05);肝组织病理学改变较轻(P<0.05);C组与D组比较,各参数无显著性差异.以上研究表明.注射用内给氧可通过改善肝细胞的能量代谢而减轻肝缺血再灌注损伤.     

丹酚酸A对大鼠脑缺血/再灌注损伤及抗氧化酶活性的影响

目的:探讨丹酚酸A对大鼠脑缺血/再灌注(cerebral ischemia/reperfusion,CI/R)损伤及抗氧化酶活性的影响。方法:采用大鼠脑中动脉闭塞(middle cerebral arteryocclusion,MCAO)2 h再灌注24 h模型。实验终末,检测脑梗死面积,脑水肿以及评价神经功能损伤,并进一步分析脑组织中三种抗氧化酶的活性水平。结果:与模型组相比,丹酚酸A组大鼠脑梗死面积显著减少(P0.05),水肿程度显著减轻(P0.05),神经功能学评分显著下降(P0.05)。模型组再灌注24 h后,SOD,GSH-PX及CAT活性显著下降(P0.05);丹酚酸A组SOD,GSH-PX及CAT活性则显著升高(P0.05)。结论:丹酚酸A对大鼠CI/R损伤具有保护作用,可能与CI/R损伤时的脑组织SOD,GSH-PX及CAT活性显著升高相关。     

姜黄素对自发性高血压大鼠海马缺血/再灌注损伤神经元凋亡核通路的影响

目的:探讨自发性高血压大鼠(SHR)脑缺血/再灌注损伤海马神经元凋亡c-Jun氨基末端激酶(JNK)核通路的变化特点,以及姜黄素对其保护作用可能机制。方法:雄性Wistar-Kyoto大鼠(WKY)和SHR,随机分为5组:WKY假手术组(W-Sham组)、缺血/再灌注组(W-I/R组)和SHR假手术组(S-Sham组)、缺血/再灌注组(S-I/R组)、姜黄素100mg/kg预处理组(S-Cur组),上述5个实验组按再灌注时间又分为再灌注2h、6h、1d、3d、7d5个亚组(n=6)。采用四动脉结扎法制备脑缺血/再灌注模型,以TUNEL法检测海马CA1区的细胞凋亡,免疫组化法分析海马CA1区c-jun、c-fos的动态变化。结果:S-Sham组大鼠海马CA1区TUNEL细胞数量和c-jun、c-fos表达高于W-Sham组(P0.05),S-I/R组TUNEL细胞数量和c-jun、c-fos表达高于S-Sham组及W-I/R组(P0.05);S-Cur组TUNEL细胞数量和c-jun、c-fos表达较S-I/R组明显降低(P0.05)。结论:缺血/再灌注更易导致SHR海马神经元凋亡。姜黄素可抑制SHR脑缺血/再灌注损伤海马神经元凋亡,其作用机制可能与抑制c-jun、c-fos蛋白的表达有关。     

两种阿尔茨海默病转基因小鼠模型脑新皮质区A(beta)分布的比较研究

目的:比较Aβ在两种阿尔茨海默病转基因小鼠模型脑新皮质区分布的差异。方法:采用18月龄雄性APP/PSl双转基因(2×Tg-AD)小鼠与同龄同性别APP/PSl/tau三转基因(3×Tg-AD)小鼠,取新皮质区脑组织行6E10单克隆抗体免疫组化染色等方法显示Aβ阳性神经元及斑块,观察其分布与形态等的差异,图像分析系统定量比较其量的变化。结果:在新皮质区2×Tg-AD组Aβ阳性产物主要位于细胞外即细胞外Aβ(e Aβ),形成大量的老年斑,细胞内阳性产物少;而3×Tg-AD组Aβ阳性产物主要位于神经元细胞内即细胞内Aβ(i Aβ),但老年斑少见。结论:2×Tg-AD组与3×Tg-AD组Aβ阳性产物在新皮质区分布的差异可能反映了两种AD小鼠模型神经病理等改变的不同。     

电针预处理对脑缺血再灌注后小胶质细胞活化状态的影响

目的:观察电针预处理对脑缺血再灌注后小胶质细胞活化状态的影响。方法:成年雄性SD大鼠随机分为假手术组(sham)、缺血组(MCAO)、电针处理组(EA+MCAO)三组。采用大脑中动脉栓塞(MCAO)诱导大鼠局灶性脑缺血再灌注模型。缺血再灌注后6 h、24 h、3 d和7 d取材,运用Western blot及免疫荧光技术检测缺血半暗带小胶质细胞活化状态以及M1/M2型特异性标志分子的表达水平。结果:脑缺血再灌注后,小胶质细胞被激活,数量表达增加(P0.05,vs.sham组),形态从静息状态的分支状转变为圆形的阿米巴状。M1型标志分子i NOS主要表达于缺血再灌注后24小时(P0.05,vs.sham组),M2型标志分子Arginase主要表达于缺血再灌注后7天(P0.05,vs.sham组)。电针预处理上调Arginase的表达水平,下调i NOS的表达水平(P0.05,vs.MCAO组)。结论:缺血再灌注后小胶质细胞被激活,电针预处理促使活化的小胶质细胞由M1向M2转化。     

牛磺酸对大鼠肢体缺血/再灌注后肺损伤时磷脂酶A2的影响

目的:探讨牛磺酸对大鼠肢体缺血/再灌注后肺损伤时磷脂酶A2(PLA2)的影响。方法:实验采用大鼠肢体缺血/再灌注损伤模型,将Wistar大鼠30只随机分为3组(n=10),对照组(control)、单纯缺血/再灌注组(I/R)、牛磺酸 缺血/再灌注组(Tau I/R),分别测定血浆丙二醛(MDA)、黄嘌呤氧化酶(XOD)、超氧化物歧化酶(SOD)以及肺组织Taurine、XOD、SOD、MDA、髓过氧化物酶(MPO)的含量、肺湿/干比值(W/D)和磷脂酶A2(PLA2)的活性。结果:口服牛磺酸可有效地降低肺组织MPO、PLA2和XOD的活性。结论:牛磺酸对大鼠肢体缺血再灌注后肺损伤具有保护作用,其机制之一可能与降低PLA2活性和抑制炎症反应有关。     

两种阿尔茨海默病转基因小鼠模型脑新皮质区Aβ分布的比较研究

目的:比较Aβ在两种阿尔茨海默病转基因小鼠模型脑新皮质区分布的差异。方法:采用18月龄雄性APP/PSl双转基因(2×Tg-AD)小鼠与同龄同性别APP/PSl/tau三转基因(3×Tg-AD)小鼠,取新皮质区脑组织行6E10单克隆抗体免疫组化染色等方法显示Aβ阳性神经元及斑块,观察其分布与形态等的差异,图像分析系统定量比较其量的变化。结果:在新皮质区2×Tg-AD组Aβ阳性产物主要位于细胞外即细胞外Aβ(e Aβ),形成大量的老年斑,细胞内阳性产物少;而3×Tg-AD组Aβ阳性产物主要位于神经元细胞内即细胞内Aβ(i Aβ),但老年斑少见。结论:2×Tg-AD组与3×Tg-AD组Aβ阳性产物在新皮质区分布的差异可能反映了两种AD小鼠模型神经病理等改变的不同。     

Neuroprotection by Curcumin in Ischemic Brain Injury Involves the Akt/Nrf2 Pathway

Oxidative damage plays a critical role in many diseases of the central nervous system. This study was conducted to determine the molecular mechanisms involved in the putative anti-oxidative effects of curcumin against experimental stroke. Oxygen and glucose deprivation/reoxygenation (OGD/R) was used to mimic ischemic insult in primary cultured cortical neurons. A rapid increase in the intracellular expression of NAD(P)H: quinone oxidoreductase1 (NQO1) induced by OGD was counteracted by curcumin post-treatment, which paralleled attenuated cell injury. The reduction of phosphorylation Akt induced by OGD was restored by curcumin. Consequently, NQO1 expression and the binding activity of nuclear factor-erythroid 2-related factor 2 (Nrf2) to antioxidant response element (ARE) were increased. {"type":"entrez-nucleotide","attrs":{"text":"LY294002","term_id":"1257998346","term_text":"LY294002"}}LY294002 blocked the increase in phospho-Akt evoked by curcumin and abolished the associated protective effect. Adult male Sprague-Dawley rats were subjected to transient middle cerebral artery occlusion for 60 minutes. Curcumin administration significantly reduced infarct size. Curcumin also markedly reduced oxidative stress levels in middle cerebral artery occlusion (MCAO) rats; hence, these effects were all suppressed by {"type":"entrez-nucleotide","attrs":{"text":"LY294002","term_id":"1257998346","term_text":"LY294002"}}LY294002. Taken together, these findings provide evidence that curcumin protects neurons against ischemic injury, and this neuroprotective effect involves the Akt/Nrf2 pathway. In addition, Nrf2 is involved in the neuroprotective effects of curcumin against oxidative damage.     

Neuroprotective effects of astaxanthin against oxygen and glucose deprivation damage via the PI3K/Akt/GSK3β/Nrf2 signalling pathway in vitro

Astaxanthin (ATX), which is the most abundant flavonoid in propolis, has previously shown neuroprotective properties against cerebral ischaemia‐induced apoptosis. However, the mechanisms by which ATX mediates its therapeutic effects are unclear. At present, we explored the underlying mechanisms involved in the protective effects of ATX via the phosphoinositide 3‐kinase (PI3K)/Akt/glycogen synthase kinase 3 beta (GSK3β)/nuclear factor erythroid 2‐related factor 2 (Nrf2) signalling pathway in SH‐SY5Y cells. The PI3K/Akt inhibitor LY294002 and GSK3β inhibitor LiCl were employed in this study. Pre‐treatment with ATX for 24 hours significantly decreased the oxygen and glucose deprivation (OGD)‐induced viability loss, reduced the proportion of apoptosis and regulated OGD‐mediated reactive oxygen species (ROS) production. Furthermore, ATX suppressed OGD‐caused mitochondrial membrane potential and decomposition of caspase‐3 to cleaved caspase‐3, and heightened the B‐cell lymphoma 2 (Bcl‐2)/Bax ratio. PI3K/Akt/GSK3β/Nrf2 signalling pathway activation in SH‐SY5Y cells was verified by Western blot. ATX and LiCl treatment raised the protein levels of p‐Akt, p‐GSK3β, nucleus Nrf2 and haeme oxygenase 1 (HO‐1). However, these protein expression levels decreased by treatment of LY294002. The above in vitro data indicate that ATX can confer neuroprotection against OGD‐induced apoptosis via the PI3K/Akt/GSK3β/Nrf2 signalling pathway.     

Overexpression of lemur tyrosine kinase-2 protects neurons from oxygen-glucose deprivation/reoxygenation-induced injury through reinforcement of Nrf2 signaling by modulating GSK-3β phosphorylation

Lemur tyrosine kinase-2 (LMTK2), a newly identified serine/threonine kinase, is a potential regulator of cell survival and apoptosis. However, little is known about its role in regulating neuronal survival during cerebral ischemia/reperfusion injury. The present study aimed to explore the potential function of LMTK2 in regulating neuronal survival using an in vitro model of oxygen-glucose deprivation/reoxygenation (OGD/R)-induced injury. Herein, we found that LMTK2 expression was markedly decreased in neurons following OGD/R exposure. Gain-of-function experiments demonstrated that LMTK2 overexpression significantly improved the viability and reduced apoptosis of neurons with OGD/R-induced injury. Moreover, LMTK2 overexpression reduced the production of reactive oxygen species (ROS) in OGD/R-exposed neurons. Notably, our results elucidated that LMTK2 overexpression reinforced the activation of nuclear factor erythroid 2-related factor (Nrf2)/antioxidant response element (ARE) antioxidant signaling associated with increased glycogen synthase kinase-3β (GSK-3β) phosphorylation. GSK-3β inhibition by its specific inhibitor significantly reversed LMTK2-inhibition-linked apoptosis and ROS production. Additionally, silencing Nrf2 partially reversed the LMTK2-overexpression-mediated neuroprotective effect in OGD/R-injured neurons. Taken together, our results demonstrated that LMTK2 overexpression alleviated OGD/R-induced neuronal apoptosis and oxidative damage by enhancing Nrf2/ARE antioxidant signaling via modulation of GSK-3β phosphorylation. Our study suggests LMTK2 is a potential target for neuroprotection during cerebral ischemia/reperfusion.     

Higenamine protects neuronal cells from oxygen-glucose deprivation/reoxygenation-induced injury

Higenamine, a plant-based alkaloid, exhibits various properties, such as antiapoptotic and antioxidative effects. Previous studies proved that higenamine possesses potential therapeutic effects for ischemia/reperfusion (I/R) injuries. However, the role of higenamine in cerebral I/R injury has not been fully evaluated. Therefore, we aimed to investigate the effect of higenamine on cerebral I/R injury and the potential mechanism. Our data showed that higenamine ameliorated oxygen-glucose deprivation/reperfusion (OGD/R)-induced neuronal cells injury. Induction of reactive oxygen species and malonaldehyde production, and the inhibition of superoxide dismutase and glutathione peroxidase activity caused by OGD/R were attenuated by higenamine. In addition, higenamine inhibited the increases in caspase-3 activity and Bax expression, and inhibited the decrease in Bcl-2 expression. Furthermore, higenamine elevated the expression levels of p-Akt, heme oxygenase-1 (HO-1) and nuclear factor erythroid 2-related factor 2 (Nrf2). The inhibitor of PI3K/Akt (LY294002) abolished the protective effects of higenamine on OGD/R-induced neuronal cells. These findings indicated that higenamine protects neuronal cells against OGD/R-induced injury by regulating the Akt and Nrf2/HO-1-signaling pathways. Collectively, higenamine might be considered as new strategy for the prevention and treatment of cerebral I/R injury.     

Duloxetine Protects Human Neuroblastoma Cells from Oxidative Stress-Induced Cell Death Through Akt/Nrf-2/HO-1 Pathway

The contribution of oxidative stress to the pathophysiology of depression has been described in numerous studies. Particularly, an increased production of reactive oxygen species (ROS) caused by mitochondrial dysfunction can lead to neuronal cell death. Human neuroblastoma SH-SY5Y cells were used to investigate the neuroprotective effect of the antidepressant duloxetine against rotenone-induced oxidative stress. SH-SY5Y cells were pretreated with duloxetine (1–5 µM) for 24 h followed by a 24-h rotenone exposure (10 µM). The phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) inhibitor LY294002 (10 µM) and the heme oxygenase 1 (HO-1) inhibitor zinc protoporphyrin IX-ZnPP (5 µM) were added to cultures 1 h prior duloxetine treatments. After treatments cell viability and ROS generation were assessed. NF-E2-related factor-2 (Nrf2) nuclear translocation was assessed by immunofluorescent staining after 4 and 8 h of duloxetine incubation. Furthermore, the Nrf2 and HO-1 mRNA expression was carried out after 4–48 h of duloxetine treatment by qRT-PCR. Duloxetine pretreatment antagonized rotenone-induced overproduction of ROS and cell death in SH-SY5Y cells. In addition, a 1-h pretreatment with LY294002 abolished duloxetine’s protective effect. Duloxetine also induced nuclear translocation of the Nrf2 and the expression of its target gene, HO-1. Finally, the HO-1 inhibitor, ZnPP, suppressed the duloxetine protective effect. Overall, these results indicate that the mechanism of duloxetine neuroprotective action against oxidative stress and cell death might rely on the Akt/Nrf2/HO-1 pathways.     

Hypoxia/Reoxygenation Stimulates Proliferation Through PKC-Dependent Activation of ERK and Akt in Mouse Neural Progenitor Cells

Cerebral ischemia increases neural progenitor cell proliferation and neurogenesis. However, the precise molecular mechanism is poorly understood. The present study was undertaken to determine roles of extracellular signal-regulated kinase (ERK) and phosphoinositide 3-kinase (PI3K)/Akt and their signaling pathways in neural progenitor cells exposed to hypoxia/reoxygenation (H/R), an in vitro model of ischemia/reperfusion. Neural progenitor cells were isolated from postnatal mouse brain. ERK and Akt were transiently activated during the early phase of reoxygenation following 4-h of hypoxia. The ERK activation was inhibited by U0126, a specific inhibitor of MEK, but not by LY294002, a specific inhibitor of PI3K, whereas the Akt activation was blocked by LY294002, but not by U0126. Reoxygenation following 4-h hypoxia stimulated cell proliferation, which was dependent on ERK and Akt activation. Inhibitors of growth factor receptor (AG1478) and Src (PP2) and the antioxidant N-acetylcysteine did not affect activation of ERK and Akt, while the Ras and Raf inhibitors inhibited activation of ERK, but not Akt. PKC inhibitors inhibited both ERK and Akt activation. Taken together, these results suggest that H/R induces activation of MEK/ERK and PI3K/Akt survival signaling pathways through a PKC-dependent mechanism. These pathways may be responsible for the repair process during ischemia/reperfusion.     

Pterostilbene protects against UVB-induced photo-damage through a phosphatidylinositol-3-kinase-dependent Nrf2/ARE pathway in human keratinocytes

Objective: Ultraviolet B (UVB) irradiation is the initial etiological factor for various skin disorders, including erythema, sunburn, photoaging, and photocarcinogenesis. Pterostilbene (Pter) displayed remarkable antioxidant, anti-inflammatory, and anticarcinogenic activities. This study aimed to investigate the effective mechanism of Pter against UVB-induced photodamage in immortalized human keratinocytes.

Methods: Human keratinocytes were pretreated with Pter (5 and 10?μM) for 24?h prior to UVB irradiation (300?mJ/cm²). Harvested cells were analyzed by MTT, DCFH-DA, comet, western blotting, luciferase promoter, small interference RNA transfection, and quantitative real-time polymerase chain reaction assay.

Results: Pter significantly attenuated UVB-induced cell death and reactive oxygen species (ROS) generation, and effectively increased nuclear translocation of NF-E2-related factor-2 (Nrf2), expression of Nrf2-dependent antioxidant enzymes, and DNA repair activity. Moreover, the protective effects of Pter were abolished by small interference RNA-mediated Nrf2 silencing. Furthermore, Pter was also found to induce the phosphorylation of Nrf2 and the known phosphatidylinositol-3-kinase (PI3K) phosphorylated kinase, Akt. The specific inhibitor of PI3K, LY294002, successfully abrogated Pter-induced Nrf2 phosphorylation, activation of Nrf2-antioxidant response element pathway, ROS scavenging ability, and DNA repair activity.

Conclusion: The present study indicated that Pter effectively protected against UVB-induced photodamage by increasing endogenous defense mechanisms, scavenging UVB-induced ROS, and aiding in damaged DNA repair through a PI3K-dependent activation of Nrf2/ARE pathway.