Adenosine A1 receptor-mediated transactivation of the EGF receptor produces a neuroprotective effect on cortical neurons in vitro

Aim： To understand the mechanism of the transactivation of the epidermal growth factor receptor （EGFR） mediated by the adenosine A1 receptor （A1R）.
Methods： Primary cultured rat cortical neurons subjected to oxygen-glucose deprivation （OGD） and HEK293/A1R cells were treated with the A1R-specific agonist N^6-cyclopentyladenosine （CPA）. Phospho-EGFR, Akt, and ERK1/2 were observed by Western blot. An interaction between EGFR and A1R was detected using immunoprecipitation and immunocytochemistry.
Results： The A1R agonist CPA causes protein kinase B （Akt） activation and protects primary cortical neurons from oxygen-glucose deprivation （OGD） insult. A1R and EGFR co-localize in the membranes of neurons and form an immunocomplex. A1R stimulation induces significant EGFR phosphorylation via a PI3K and Src kinase signaling pathway; this stimulation provides a neuroprotective effect in cortical neurons. CPA leads to sustained phosphorylation of extracellularly regulated kinases 1 and 2 （ERK1/2） in cortical neurons, but only to transient phosphorylation in HEK 293/A1R cells. The response to the A1R agonist is mediated primarily through EGFR transactivation that is dependent on pertussis toxin （PTX）-sensitive G1 protein and metalloproteases in HEK 293/A1R.
Conclusion： A1R-mediated EGFR transactivation confers a neuroprotective effect in primary cortical neurons. PI3 kinase and Src kinase play pivotal roles in this response.     

Involvement of cyclin dependent kinase 5 and its activator p35 in staurosporine-induced apoptosis of cortical neurons

AIM: To investigate whether cyclin-dependent kinase 5 and its regulatory protein p35 was involved in staurosporine-induced apoptosis of cortical neuronal cultures. METHODS: Primary cerebral cortical neurons were exposed to 300nmol/L staurosporine. After incubation for different time, morphological alterations were observed with phasecontrast microscopy, fluorescence microscopy, and transmission electron microscopy. DNA fragmentation was detected by agarose gel electrophoresis. The protein levels of Cdk4, p53, Cdk5, and its regulatory protein p35 following staurosporine treatment were measured by Western blotting. The Cdk5 activity was assayed for histone H1 kinase activity by autoradiography. RESULTS: The typical morphological changes of apoptosis were observed and the nuclear DNA fragmentation showed the characteristic “ladder” pattern after the cells were treated by staurosporine. The Cdk5 protein level increased markedly at 3h and continued to 24h. The p35 level increased at 3h after being exposed to staurosporine, and decreased at 12h. The cleavage of p35 to p25 was also detected at 12h and increased at 24h. There was no increase in Cdk5 kinase activity despite the increased cleavage of p35.The protein level of Cdk4 protein increased at 3h and then decreased gradually from 6h, but it was still higher than that in the vehicle cultures at 12h. The p53 level decreased obviously at 3h after staurosporine treatment and then seemed to increase at 12h, but remained lower than that of vehicle cultures. CONCLUSION: Staurosporine-induced increase in Cdk5 protein levels and the cleavage of p35 to p25 may contribute to neuronal apoptosis.     

Activation of c—Jun and suppression of phospho—p44／42 were involved in diphenylhydantoin—induced apoptosis of cultured rat cerebellar granule neurons

AIM:To investigate possible intracellular signal molecules involved in diphenylhydantoin (DPH)-mediated apoptosis of cerebellar granule neurons (CGN) and explore possible nolecular mechanisms of neurotoxicity of DPH.METHODS: Fluorescein diacetate (FDA) stain, hochest 33258 stain, and agar gel electrophoresis were used to test morphological and biological characters of primary CGN and cortical neurons (CN) in the presence or absence of 100μmol/L DPH; Western blot and RT-PCR were employed to further investigate apoptotic/survival signal moleculars involved in the neuronal apoptotic signal transdution. RESULTS:DPH 100μmol/L induced a typical apoptosis of CGN but had no toxicity on CN. Cerebellar granule neural apoptosis induced by 100μmol/L DPH was significantly inhibited by pre-treatment with SB203580(10μmol/L) or CEP-11004(1μmol/L) for 1h. DPH markedly upregulated the levels of phospho-c-Jun (active c-Jun), total c-Jun protein and c-jun mRNA in CGN. The levels of phospho-c-Jun dramatically elevated by DPH at 8 h were significantly inhibited by SB203580(10μmol/L) or CEP-11004 (1μmol/L). Moreover, the activities of p44/42 (ERK1/ERK2), other members of MAP kinases and generally believed to be important survival effetors in CGN, were markedly suppressed. However, the activities of both JNK and p38 were little affected in the process of apoptosis of CGN induced by 100μmol/L DPH. CONCLUSION: The selective toxicity of DPH on CGN is likely due to its ability to induce apoptosis of CGN, it is a process involved activation of c-Jun and suppression of the activity of p44/42.     

Homeostatic conditions affect the protective effect of edaravone on ischemic injury in neurons

Objective：To determine whether homeostatic conditions （pH, glycine or ion concentration） affect the protective effects of edaravone on ischemic injury in rat cortical neurons. Methods： In cultured rat cortical neurons, the compositions in the experimental solutions were changed to mimic the disturbance of homeostasis after cerebral ischemia. In vitro ischemic injury was induced by oxygen - glucose deprivation （OGD） for 3 h and reperfusion for 12 h, and the neuron injury was evaluated by 3 - （4,5 - dimethyhhiazol - 2yl） - 2,5 - diphenyl tetrazolium bromide （MTY） reduction assay and lactate dehydrogenase （LDH） release. Effect of edaravone on OGD injury was observed in different experimental solutions.     

Neuroprotection by sodium ferulate against glutamate-induced apoptosis is mediated by ERK and PI3 kinase pathways

Aim： To investigate whether sodium ferulate （SF） can protect cortical neurons from glutamate-induced neurotoxicity and the mechanisms responsible for this protection. Methods： Cultured cortical neurons were incubated with 50 μmol/L glutamate for either 30 min or 24 h, with or without pre-incubation with SF （100, 200, and 500 pmol/L, respectively）. LY294002, wortmannin, PD98059, and U0126 were added respectively to the cells 1 h prior to SF treatment. After incubation with glutamate for 24 h, neuronal apoptosis was quantified by scoring the per- centage of cells with apoptotic nuclear morphology after Hoechst 33258 staining. After incubation with glutamate for either 30 rain or 24 h, cellular extracts were prepared for Western blotting of active caspase-3, poly （ADP-ribose） polymerase （PARP）, μ-calpain, Bcl-2, phospho-Akt, phosphorylated ribosomal protein S6 pro- tein kinase （p70S6K）, phospho-mitogen-activated protein kinase kinase （MEK1/2） and phosphorylated extracellular signal-regulated kinase （ERK） 1/2. Results： SF reduced glutamate-evoked apoptotic morphology, active caspase-3 protein expression, and PARP cleavage and inhibited the glutamate-induced upregulation of the ~-calpain protein level. The inhibition of the phosphatidylinositol 3-kinase （P13K） and the MEK/ERK1/2 pathways partly abrogated the protective effect of SF against glutamate-induced neuronal apoptosis. SF prevented the glutamate- induced decrease in the activity of the PI3K/Akt/p70S6K and the MEK/ERK1/2 pathways. Moreover, incubation of cortical neurons with SF for 30 min inhibited the reduction of the Bcl-2 expression induced by glutamate. Conclusion： The results indicate that PI3K/Akt/p70S6K and the MEK/ERK signaling pathways play important roles in the protective effect of SF against glutamate toxicity in cortical neurons.     

Protective effect of tubuloside B on TNFα-induced apoptosis in neuronal cells

AIM: To investigate the neuroprotective effect of tubuloside B, one of the phenylethanoids isolated from the stems of Cistanche salsa, on tumor necrosis factor-alpha (TNFα)-induced apoptosis in SH-SY5Y neuronal cells. METHODS: Cell viability was analyzed using MTT assay. Apoptotic cells were detected using Hoechst33342 staining, and confirmed by DNA fragmentation and flow cytometric analysis. The activity of caspase-3 was measured with special assay kit. The concentration of free intracellular calcium was determined with the probe Indo-1 by spectrometer. The level of intracellular reactive oxygen species and the potential of mitochondrial membrane were determined by laser scanning confocal microscopy (LSCM) combined with fluorescence probe H2DCFDA or JC-1 respectively. RESULTS: SH-SY5Y cells treated with TNFα 100 μg/L for 36 h showed typical morphological changes of apoptosis. DNA ladder could be observed by agarose gel electrophoresis. The highest percentage of apoptotic cells accumulated to 37.5 %. Following 36 h treatment with TNFα, accumulation of intracellular ROS and [Ca^2 ]i and decrease in mitochondrial membrane potential were observed, and caspase-3 activity increased by about five-fold compared with controls. However, pretreatment with tubuloside B (1, 10, or 100 mg/L) for 2 h attenuated the TNFα-mediated apoptosis. The antiapoptotic action of tubuloside B was partially dependent on an anti-oxidative stress effects, maintain of mitochondria function, decrease of concentration of free intracellular calcium and inhibition of caspase-3 activity. CONCLUSION: Tubuloside B has the neuroprotective capacity to antagonize TNFo~-induced apoptosis in SH-SY5Y cells and may be useful in treating some neurodegenerative diseases.     

Hydrogen sulfide inhibits homocysteine-induced endoplasmic reticulum stress and neuronal apoptosis in rat hippocampus via upregulation of the BDNF-TrkB pathway

Aim： Homocysteine （Hcy） can elicit neuronal cell death, and hyperhomocysteinemia is a strong independent risk factor for Alzheimer’s disease. The aim of this study was to examine the effects of hydrogen sulfide （H2S） on Hcy-induced endoplasmic reticulum （ER） stress and neuronal apoptosis in rat hippocampus.
Methods： Adult male SD rats were intracerebroventricularly （icv） injected with Hcy （0.6 μmol/d） for 7 d. Before Hcy injection, the rats were treated with NaHS （30 or 100 μmol·kg^-1·d^-1, ip） and/or k252a （1 μg/d, icv） for 2 d. The apoptotic neurons were detected in hippocampal coronal slices with TUNEL staining. The expression of glucose regulated protein 78 （GRP78）, C/EBP homologous protein （CHOP）, cleaved caspase-12, and BDNF in the hippocampus were examined using Western blotting assays. The generation of H2S in the hippocampus was measured with the NNDPD method.
Results： Hcy markedly inhibited the production of endogenous H2S and increased apoptotic neurons in the hippocampus. Further-more, Hcy induced ER stress responses in the hippocampus, as indicated by the upregulation of GRP78, CHOP, and cleaved caspase-12. Treatment with the H2S donor NaHS increased the endogenous H2S production and BDNF expression in a dose-dependent manner, and significantly reduced Hcy-induced neuronal apoptosis and ER stress responses in the hippocampus. Treatment with k252a, a specific inhibitor of TrkB （the receptor of BDNF）, abolished the protective effects of NaHS against Hcy-induced ER stress in the hippocampus.
Conclusion： H2S attenuates ER stress and neuronal apoptosis in the hippocampus of Hcy-treated rats via upregulating the BDNF-TrkB pathway.     

Liquiritigenin inhibits Aβ25-35-induced neurotoxicity and secretion of Aβ1-40 in rat hippocampal neurons

Aim： To examine whether liquiritigenin, a newly found agonist of selective estrogen receptor-β, has neuroprotective activity against β-amyloid peptide （Aβ） in rat hippocampal neurons.
Methods： Primary cultures of rat hippocampal neurons were pretreated with liquiritigenin （0.02, 0.2, and 2 pmol/L） prior to Aβ25-35 exposure. Following treatment, viability of the cells was measured by 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide analysis and by a lactate dehydrogenase activity-based cytotoxicity assay. Intracellular Ca^2＋ concentration （[Ca^2＋]i） and levels of reactive oxygen species （ROS）, as well as apoptotic rates, were determined. Our studies were extended in tests of whether liquiritigenin treatment could inhibit the secretion of Aβ1-40 as measured using an ELISA method. In order to analyze which genes may be involved, we used a microarray assay to compare gene expression patterns. Finally, the levels of specific proteins related to neurotrophy and neurodenegeration were detected by Western blotting.
Results： Pretreated neurons with liquiritigenin in the presence of Aβ25-35 increased cell viability in a concentration-dependent manner. Liquiritigenin treatment also attenuated Aβ25-35-induced increases in [Ca^2＋]i and ROS level and decreased the apoptotic rate of neurons. Some genes, including B-cell lymphoma/leukemia-2 （Bcl-2）, neurotrophin 3 （Ntf-3） and amyloid [3 （A4） precursor protein-binding, family B, member 1 （Apbb-1） were regulated by liquiritigenin; similar results were shown at the protein level by Western blotting.
Conclusion： Our results demonstrate that liquiritigenin exhibits neuroprotective effects against Aβ25-35-induced neurotoxicity and that it can decrease the secretion of Aβ1-40. Therefore, liquiritigenin may be useful for further study as a prodrug for treatment of Alzheimer＇s disease.     

Noble dendrobium polysaccharides protects neuron against LPS-induced neurotoxicity in primary rat neuron/microglia culture

OBJECTIVE To investigate the protective effect of Noble dendrobium polysaccharides(NDP) on inflammatory factors,which are produced and released by 1ipopolysaecharide(LPS)-activated rat cerebral microglia,and to explore the protective mechanisms of NDP against LPS-induced neuron damage.METHODS The whole brains of 1 or 2-day-old mice was dissected,and microglia were isolated and cultured.Before exposure to LPS neurotoxicity,cells were treated with NDP(24 h),and the microglia-conditioned medium(MCM) collected.Primary neuronal cultures were supplemented with the 24 h MCM.The morphology and density of neuronal synapses were observed by immunofluorescence;the production of NO was detected with the Griess reagent;the level of tumor necrosis factor-α(TNF-α) was assessed by ELISA;the degree of neuronal apoptosis was examined with Hoechst 33258.RESULTS The hippocampal neurons were apparently damaged by the supernatant of activated MCM,and the morphology of the neurons changed significantly.Compared to control group,the level of NO was elevated and the expression level of TNF-α protein was significantly increased,and the apoptosis was induced in neurons.NDP improved synaptic morphology and increase synapses density,depress the high-level of NO,inhibited the up-expression of TNF-α protein by LPS,and decreased neuronal apoptosis.CONCLUSION NDP may significantly inhibit the activation of microglia induced by LPS and reduce the release of inflammatory factors.These results showed that NDP exert neuroprotection through depressing the actived microglia.     

牛磺酸对皮质神经元急性氧糖缺失所致损伤的保护作用(英文)

目的已证实牛磺酸对在体脑缺血有保护作用,本研究观察其对缺失氧糖的离体神经元是否有直接的保护作用及可能的作用机制。方法制备离体大鼠脑皮质神经元的氧糖缺失模型。在氧糖缺失前20 h及氧糖缺失4 h过程中,分别给予牛磺酸5,10和20 mmol·L-1。MTT法和流式细胞术检测神经元的死亡率;Fura-2/AM负载检测神经元内游离钙离子水平([Ca2 +]i);高效液相色谱法检测培养基中谷氨酸水平。结果氧糖缺失可致神经元死亡增加,[Ca2 +]i和培养基中谷氨酸水平异常升高;牛磺酸处理可使氧糖缺失引起的神经元死亡率明显降低,抑制氧糖缺失引起的神经元[Ca2 +]i和胞外谷氨酸浓度的异常升高。结论牛磺酸可以减轻氧糖缺失引起的大鼠皮质神经元损伤,其机制可能与其抑制胞内钙超载和抑制谷氨酸释放或漏出有关。     

辛伐他汀通过内质网应激途径诱导K562细胞凋亡

探讨内质网应激在辛伐他汀诱导K562细胞凋亡中的作用。采用荧光显微镜观察凋亡细胞的形态变化，AnnexinV-FITC/PI双染法检测细胞凋亡率，激光扫描共聚焦显微镜检测细胞内Ｃa²⁺浓度，RT-PCR检测葡萄糖调节蛋白78(glucose regulated protein 78，GRP78)、钙蛋白酶(calpain)基因mRNA表达水平，Western blotting检测GRP78、 calpain、 caspase-3， -6， -7， -9， -12蛋白水平。结果显示，10、 20、 30 μmol·L^-1辛伐他汀(simvastatin，Sim)作用K562细胞72 h后，细胞出现典型的凋亡形态，凋亡率分别为12.41%、 19.08%和23.41%；细胞内Ca²⁺浓度增加，荧光强度分别为43、54和64；GRP78、calpain基因mRNA表达上调；calpain、 caspase-3， -6， -7， -9， -12蛋白剪切活化、GRP78蛋白表达增强。以上结果表明，内质网作为细胞凋亡的重要途径参与了辛伐他汀诱导K562细胞的凋亡。辛伐他汀将可能被用于临床治疗白血病。     

细胞保护作用是抗抑郁剂作用的共同通路之一

目的：探讨抗抑郁剂可能的共同作用机制。方法：以MTT比色法检测细胞活性状态;以Fura 2-AM荧光标记法测定胞内Ca^2 浓度：以RT-PCR法检测神经生长因子(NGF)mRNA水平。结果：以高浓度皮质酮0．2mmol/L处理PC12细胞48h以模拟抑郁症脑神经细胞损伤状态,发现目前三类经典抗抑郁剂,包括三环抗抑郁剂地昔帕明(DIM)0．625—10μmol／L,5-HT重摄取抑制剂氟西丁(FLU)0．625—10μmol／L,单胺氧化酶A抑制剂马氯贝胺(MOC)2．5—40μmol／L对皮质酮损伤的PC12细胞具有显著的保护作用,而抗精神病药氯丙嗪和抗焦虑药地西泮无此作用、DIM1,5μmol/L或FLU1,5μmol/L几显著减弱皮质酮0．1mmol／L处理PC12细胞48h诱导的胞内Ca^2 超载,进一步研究发现,DIM或FLU 10μmol／L处理PC12细胞48h显著提高NGF mRNA的表达水平。结论：尽管各类抗抑郁剂结构迥异,但细胞保护作用可能是其共同作用通路,而减弱胞内Ca^2 超载和提高NGF等神经营养因子的表达是抗抑郁药的细胞保护作用机制之一。     

Dual effect of the antianginal drug fendiline on bladder female transitional carcinoma cells: mobilization of intracellular CA2+ and induction of cell death

The effect of fendiline, an antianginal drug, on cytosolic free Ca2+ levels ([Ca2+]i) in populations of bladder female transitional carcinoma (BFTC) cells was explored using fura-2 as a Ca2+ indicator. Fendiline at concentrations between 3 and 200 micromol/l increased [Ca2+]i in a concentration-dependent manner and the signal saturated at 100 micromol/l. The [Ca2+]i signal was biphasic, with an initial rise and a slow decay. Ca2+ removal inhibited the Ca2+ signal by about half in peak amplitude. Adding 3 mmol/l Ca2+ increased [Ca2+]i in cells pretreated with 100 micromol/l fendiline in Ca2+ -free medium, suggesting that fendiline induced Ca2+ influx via capacitative Ca2+ entry. In Ca2+ -free medium, pretreatment with 1 micromol/l thapsigargin (an endoplasmic reticulum Ca2+ pump inhibitor) to deplete the endoplasmic reticulum Ca2+ store inhibited most of the 100 micromol/l fendiline-induced internal Ca2+ release; and conversely, pretreatment with 100 micromol/l fendiline partly inhibited 1 micromol/l thapsigargin-induced Ca2+ release. This indicates that the major internal Ca2+ store of fendiline-induced [Ca2+]i increases is located in the endoplasmic reticulum. The Ca2+ release induced by 100 micromol/l fendiline may be partly mediated by inositol 1,4,5-trisphosphate, because the [Ca2+]i increase was inhibited by 50% by inhibiting phospholipase C with 2 micromol/l U73122. Fendiline (100 micromol/l) decreased cell viability by 12-44% after being added to cells for 2- 30 min. Together, the findings indicate that in BFTC cells, fendiline exerts a dual effect: mobilization of intracellular Ca2+ and induction of cell death.     

Endothelium-derived hyperpolarizing factor but not NO reduces smooth muscle Ca2+ during acetylcholine-induced dilation of microvessels.

1. We hypothesized that nitric oxide (NO) and the endothelium-dependent hyperpolarizing factor (EDHF) may dilate microvessels by different cellular mechanisms, namely Ca2+-desensitization versus decrease in intracellular free calcium. 2. Effects of acetylcholine (ACh) and the NO donors sodium nitroprusside (SNP, 0.1 - 10 micromol l(-1)) and S-Nitroso-N-acetyl-D, L-penicillamine (SNAP, 0.01 - 10 micromol l-1) on intracellular calcium ([Ca2+]i, fura 2) and vascular diameter (videomicroscopy) were studied in isolated resistance arteries from hamster gracilis muscle (194+/-12 microm) pretreated with indomethacin and norepinephrine. Membrane potential changes were determined using 1, 3-dibutylbarbituric acid trimethineoxonol (DiBAC4(3)). 3. ACh (0.1 and 1 micromol l-1)-induced dilations were associated with a [Ca2+]i decrease (by 13+/-3 and 32+/-4%) and hyperpolarization of vascular smooth muscle (VSM, by 12+/-1% at 1 micromol l-1 ACh). Nomega-nitro-L-arginine (L-NA, 30 micromol l(-1)) partially inhibited the dilation but did not affect VSM [Ca2+]i decreases or hyperpolarization. In contrast, the KCa channel inhibitors tetrabutylammonium (TBA, 1 mmol l(-1)) and charybdotoxin (ChTX, 1 micromol l(-1)) abolished the ACh-induced [Ca2+]i decrease and the hyperpolarization in VSM while a significant dilation remained (25 and 40%). This remaining dilation was abolished by L-NA. ChTX did not affect [Ca2+]i increase and hyperpolarization in endothelial cells. SNP- or SNAP-induced dilations were not associated with decreases in VSM [Ca2+]i or hyperpolarization although minor transient decreases in VSM [Ca2+]i were observed at high concentrations. 4. These data suggest that ACh-induced dilations in microvessels are predominantly mediated by a factor different from NO and PGI2, presumably EDHF. EDHF exerts dilation by activation of KCa channels and a subsequent decrease in VSM [Ca2+]i, NO dilates the microvessels in a calcium-independent manner.     

Neuroprotective effects of oxysophocarpine on neonatal rat primary cultured hippocampal neurons injured by oxygen-glucose deprivation and reperfusion

Context: Oxysophocarpine (OSC), a quinolizidine alkaloid extracted from leguminous plants of the genus Robinia, is traditionally used for various diseases including neuronal disorders.

Objective: This study investigated the protective effects of OSC on neonatal rat primary-cultured hippocampal neurons were injured by oxygen–glucose deprivation and reperfusion (OGD/RP).

Materials and methods: Cultured hippocampal neurons were exposed to OGD for 2?h followed by a 24?h RP. OSC (1, 2, and 5?μmol/L) and nimodipine (Nim) (12?μmol/L) were added to the culture after OGD but before RP. The cultures of the control group were not exposed to OGD/RP. MTT and LDH assay were used to evaluate the protective effects of OSC. The concentration of intracellular-free calcium [Ca²⁺]_i and mitochondrial membrane potential (MMP) were determined to evaluate the degree of neuronal damage. Morphologic changes of neurons following OGD/RP were observed with a microscope. The expression of caspase-3 and caspase-12 mRNA was examined by real-time quantitative PCR.

Results: The IC₅₀ of OSC was found to be 100?μmol/L. Treatment with OSC (1, 2, and 5?μmol/L) attenuated neuronal damage (p?p?p?2+]_i (p?p?p?Discussion and conclusion: The results suggested that OSC has significant neuroprotective effects that can be attributed to inhibiting endoplasmic reticulum (ER) stress-induced apoptosis.     

Polygalasaponin F inhibits neuronal apoptosis induced by oxygen‐glucose deprivation and reoxygenation through the PI3K/Akt pathway

Cerebral ischaemia is a common cerebrovascular disease and often induces neuronal apoptosis, leading to brain damage. Polygalasaponin F (PGSF) is one of the components in Polygala japonica Houtt, and it is a triterpenoid saponin monomer. This research focused on anti‐apoptotic effect of PGSF during oxygen‐glucose deprivation and reoxygenation (OGD/R) injury in rat adrenal pheochromocytoma cells (PC12) and primary rat cortical neurons. OGD/R treatment reduced viability of PC12 cells and primary neurons. This reduced viability was prevented by PGSF, as shown by MTT assay. OGD/R insult decreased expression of Bcl‐2/Bax both in PC12 cells and primary neurons but elevated levels of caspase‐3 in primary neurons. However, PGSF may up‐regulate expression of Bcl‐2/Bax and down‐regulate caspase‐3 in these particular cells. Furthermore, Bcl‐2/Bax and the ratio between phosphorylated Akt and total Akt were decreased in PC12 cells treated with OGD/R, and both were increased by PGSF. Moreover, increase in the ratios of Bcl‐2/Bax and phosphorylated Akt/total Akt in PC12 cells was suppressed by phosphatidylinositol 3‐kinase (PI3K) inhibitor. Data suggest PGSF might prevent OGD/R‐induced injury via activation of PI3K/Akt signalling. The ability of PGSF to block the effects of OGD/R appears to involve regulation of Bcl‐2, Bax and caspase‐3, which are related to apoptosis.     

丁基苯酞抗大鼠大脑皮质神经元氧糖剥夺/复氧损伤及其机制

本研究探讨丁基苯酞抗大鼠大脑皮质神经元氧糖剥夺/复氧损伤及其机制。原代培养大鼠大脑皮质神经元，建立氧糖剥夺/复氧模型(OGD/R)，采用MTT法、酶学检查、免疫组化、RT-PCR等观察丁基苯酞(各浓度组)的保护作用及其机制。在氧糖剥夺4 h/复氧8 h时丁基苯酞各浓度组可增加神经元的细胞活力和减少神经元LDH(乳酸脱氢酶)的释放，可显著降低神经元表达iNOS mRNA(诱生型一氧化氮合酶)和NF-κB(核因子κB) p65蛋白(增加)。不同剂量丁基苯酞(100、 10、 1和0.1 μmol·L^-1)在增加细胞活力、减少LDH释放及降低神经元表达iNOS mRNA等方面，高浓度的作用强于低浓度，且丁基苯酞100 μmol·L^-1组与吡咯烷二硫代氨基甲酸酯(pyrrolidine dithiocarbamate，PDTC) 100 μmol·L^-1组差异显著。在OGD 4 h/R 8 h时丁基苯酞可能抑制iNOSmRNA的表达及NF-κB的活化，从而有效保护氧糖剥夺/复氧中损伤的大脑皮质神经元。     

Effects of econazole on Ca2+ levels in and the growth of human prostate cancer PC3 cells

1. Econazole is used clinically as an antifungal drug with many different in vitro effects. However, the effects of econazole on prostate cancer cells are unknown. The effects of econazole on intracellular Ca2+ concentrations ([Ca2+]i) in and the proliferation of human PC3 prostate cancer cells was explored in the present study using fura-2 and tetrazolium as fluorescent dyes. 2. At a concentration of 0.1 micromol/L, econazole started to increase [Ca2+]i in a concentration-dependent manner. The econazole-induced increase in [Ca2+]i was reduced by 48% by removal of extracellular Ca2+, suggesting that the econazole-induced increase in [Ca2+]i was composed of extracellular Ca2+ influx and intracellular Ca2+. 3. This econazole-induced Ca2+ influx was via an L-type Ca2+ channel-like pathway. In Ca2+-free medium, 1 micromol/L thapsigargin, an inhibitor of the endoplasmic reticulum Ca2+-ATPase, caused a monophasic increase in [Ca2+]i, after which the effect of econazole to increase [Ca2+]i was substantially inhibited. Conversely, pretreatment with 5 micromol/L econazole to deplete intracellular Ca2+ stores totally prevented thapsigargin from releasing more Ca2+. 4. The phospholipase C (PLC) inhibitor U73122 (2 micromol/L) abolished the increase in [Ca2+]i induced by 10 micromol/L ATP (a Ca2+ mobilizer that needs inositol 1,4,5-trisphosphate). 5. Overnight incubation with 1-30 micromol/L econazole inhibited proliferation of PC3 cells in a concentration-dependent manner. 6. These findings suggest that, in PC3 cells, econazole increases [Ca2+]i by stimulating Ca2+ influx into cells and Ca2+ release from the endoplasmic reticulum via a PLC-independent mechanism. Econazole is cytotoxic at submicromolar concentrations.     

Monosialoganglioside protected ischemic rat hippocampal slices through stabilizing expression of N-methyl-D-aspartate receptor subunit

INTRODUCTION Monosialoganglioside(GM1) can alleviatecerebraledema and reduce cerebral infarct volume in in vivoanimal models[1-3], and can prevent death of culturedgranule cells in vitro from anoxia as well[4]. However,meaning of data derived from a neural preparation with-out a vasculature and mammalian systemicinteractionis limited. The direct protective effect of GM1 on is-subunits are mainly distributed in the forebrain[5], and μmol/L (control group), 0.01 μmol/L(gr…