Ultrastructural confirmation of neuronal protection by melatonin against the neurotoxin 6-hydroxydopamine cell damage

6-Hydroxydopamine (6-OHDA) is a neurotoxin used in the induction of experimental Parkinson's disease in both animals and cultured neuronal cells. Biochemical and molecular approaches showed previously that low doses of 6-OHDA induced apoptosis in PC12 cells, while high doses of this neurotoxin induced necrosis. Melatonin has been shown to protect against the neuronal programmed cell death induced by 6-OHDA, although it was not able to prevent the massive necrotic cellular death occurring after the addition of high doses of the neurotoxin. In the present work, we demonstrate by ultrastructural analysis that although low doses of 6-OHDA induced apoptosis in PC12 cells, it also damaged the non-apoptotic cells, morphologically corresponding this damage to incipient and reversible necrotic lesions. When the doses of the neurotoxin increase, there are still apoptotic cells, although most of the cells show necrotic irreversible lesions. We also found that melatonin partially prevents the incipient necrotic lesions caused by low doses of 6-OHDA. The fact that melatonin was shown in previous work to prevent apoptosis caused by low doses of 6-OHDA, but not necrosis induced by high doses of the neurotoxin, seemed to indicate that this agent is only able to protect against apoptosis. However, our present results, melatonin preventing also the incipient necrotic neuronal lesions, suggest that this hormone may provide a general protection against cell death, suggesting that higher doses should be tried in order to prevent the necrotic cell death induced by high doses of the neurotoxin.     

脱位晶状体摘出联合后房型人工晶状体缝线固定术

目的　探讨晶状体脱位手术摘出联合Ⅰ期后房型人工晶状体缝线固定的临床疗效。方法　对１５眼脱位晶状体,其中Ｍａｒｆａｎ 综合征２ 眼、钝挫性晶状体脱位７ 眼、确诊为单纯性晶状体脱位３ 眼、白内障囊外摘出术中晶状体脱入玻璃体内３ 眼进行晶状体摘出联合后房型人工晶状体缝线固定术。结果　术后视力在０．１ 以上者１３ 眼（８６．７％ ）,０．５ 以上者９眼（６０％ ）;主要手术并发症：前房少量出血、高眼压、虹膜炎性反应、玻璃体腔内出血,术后１～２ｗ ｋ 均得到控制。结论　此术式是一种安全有效、视力恢复满意的治疗方法,可获得好的临床效果。     

环维黄杨星D对实验性脑缺血的保护作用

目的：探讨环维黄杨星D(Cycloirobuxiure D，CVB-D)对大鼠局灶性脑缺血再灌注损伤及PC12细胞缺氧性损伤的保护作用。方法：采用线栓法制成局灶性脑缺血再灌注大鼠模型和连二亚硫酸钠(Na2S2O4)引起的PC12细胞缺氧损伤模型，探讨CVB-D对模型大鼠神经行为、脑梗塞范围、脑含水量、脑指数的影响，以及其对PC12细胞缺氧样损伤的保护作用。结果：CVB-D能降低模型大鼠神经行为学评分、脑梗塞率、脑指数、脑含水量，抑制Na2S2O4造成的PC12细胞缺氧样损伤，降低LDH的漏出，增加细胞存活率。结论：CVB-D对实验性脑缺血有保护作用。     

丙泊酚对N-甲基-D-天冬氨酸所致PC12细胞损伤的保护作用

目的　探讨静脉麻醉药丙泊酚 (PPF)脑保护作用的可能机制。方法　乳酸脱氢酶 (LDH)法及MTT比色法判断细胞损伤程度及细胞存活率 ,Fura 2 /AM荧光标记法测定细胞内Ca2 + 浓度 ( [Ca2 + ]i)的变化 ,分光光度法测定细胞一氧化氮合酶 (NOS)活性。结果　N 甲基 D 天冬氨酸 (NMDA) 3 0 0 μmol·L-1处理4h可明显导致PC1 2细胞的损伤 ,表现为LDH释放量明显增加 ,吸光度值A570nm明显降低 ,细胞存活率降低 ,同时 [Ca2 + ]i 和NOS活性则明显增加。PPF6.2 5 ,2 5 ,1 0 0 ,40 0 μmol·L-1与NMDA同时处理PC1 2细胞则使LDH释放量显著降低 ,细胞存活率增加。PPF 1 2 .5和 1 2 5 μmol·L-1可显著降低NMDA诱导的[Ca2 + ]i 水平及NOS活性的提高。结论　PPF对NMDA所致的PC1 2细胞损伤有明显的保护作用 ,其机制可能与其抑制NMDA受体的功能 ,降低 [Ca2 + ]i,减弱Ca2 + 超载 ,并降低NMDA诱导的NOS活性增加有关。提示PPF可能是通过抑制NMDA受体 Ca2 + NOS通路的功能而产生细胞保护效应     

KP544 amplifies the effects of nerve growth factor on cell differentiation and is neuroprotective

The ability of endogenous neurotrophins, including nerve growth factor (NGF), to promote the survival and development of neurons provides convincing evidence for their therapeutic potential, despite significant barriers to their successful clinical use. Many of these barriers might be surmountable, however, by strategies that enhance endogenous neurotrophin signaling. We evaluated a series of substituted pyrimidines for their ability to enhance the effects of NGF. KP544 [2‐amino‐5‐(4‐chlorophenylethynyl)‐4‐(4‐trans‐hydroxycyclohexylamino) pyrimidine] amplified NGF‐induced neurite outgrowth of PC12 cells approximately 2‐fold at 2 µM. KP544 also enhanced choline acetyltransferase activity, a marker of differentiation induced by either NGF or by cyclic AMP, by 3‐ to 8‐fold, with a 2‐fold amplification at 0.12–0.3 µM. This amplification occurred at all concentrations of NGF used including those that maximally stimulated the cells. KP544 did not increase the levels of phosphorylated mitogen‐activated protein kinases (MAPK) above that seen with NGF alone. These studies suggested that KP544 functions within the cell at a site that is downstream from or independent of MAPK signaling. NGF‐induced neurite outgrowth in a human cell line (SH‐SY5Y neuroblastoma cells) was also enhanced with KP544 treatment. Primary embryonic rat cortical cultures were used to extend the observations beyond the studies with the immortalized cell lines. In addition to effects on neurite outgrowth, KP544 protected these cells from glutamate‐induced death. Overall, the data suggest that KP544 can selectively interact in the differentiation pathway downstream of MAPK in a manner that amplifies nerve growth factor and cyclic AMP effects and is also neuroprotective. Drug Dev. Res. 62:49–59, 2004. © 2004 Wiley‐Liss, Inc.     

当归芍药散防治老年期痴呆的物质基础与作用机理研究VI——当归芍药散精简方含药脑脊液对PC12细胞的保护作用

目的通过观察当归芍药散精简方(FBD)含药脑脊液对不同因素所致的PC12细胞损伤模型的保护作用,来探讨当归芍药散精简方(FBD)防治痴呆的作用机理.方法以MTT法观察FBD含药脑脊液对谷氨酸、过氧化氢、连二亚硫酸钠和氯化钾造成的PC12细胞损伤模型中细胞存活率的影响.结果连续多次给药(1.62g生药·kg-1)后0.5h～2.5h的FBD含药脑脊液对过氧化氢损伤的PC12细胞均有明显保护作用(P＜0.05～0.01),其中以1.5h的FBD含药脑脊液保护作用最明显;该时间点FBD含药脑脊液对谷氨酸、连二亚硫酸钠和氯化钾造成的PC12细胞损伤模型亦有显著保护作用,且随脑脊液添加量增加保护率捉高.结论FBD含药脑脊液对PC12细胞损伤有显著保护作用,其机制与抑制细胞内钙超载、对抗自由基的氧化损伤和谷氨酸的兴奋性毒性等有关.     

一氧化氮诱导PC12细胞凋亡及芍药苷的保护作用

目的:探讨一氧化氮诱导PC12细胞凋亡及芍药苷保护作用的可能机制.方法:MTT和乳酸脱氢酶活性测定细胞存活率,DNA凝胶电泳观察DNA的断裂情况,流式细胞仪测定细胞凋亡率、检测线粒体跨膜电位.结果:500 μmol·L-1 硝普钠(SNP)可诱导PC12细胞凋亡,细胞线粒体跨膜电位明显下降.预先经过 0.1、1和10 μmol·L-1 等浓度芍药苷处理后, SNP诱导的PC12细胞凋亡明显减少,同时明显减弱一氧化氮对线粒体跨膜电位的影响.结论:芍药苷可抑制一氧化氮诱导PC12细胞凋亡,其作用机制可能与其稳定细胞线粒体跨膜电位有关.     

大豆异黄酮活性组分对H2O2诱导的PC12细胞损伤的影响

目的:探讨大豆异黄酮活性组分对H2 O2 诱导的PC12细胞损伤的保护作用。方法:以H2 O2 损伤PC12细胞为氧化应激损伤的模型,采用光学显微镜观察细胞形态,MTT法判断细胞的存活率,LDH法检测细胞的损伤程度。结果:不同浓度大豆异黄酮能明显改善H2 O2 导致的细胞甲瓒减少,大豆异黄酮处理组细胞存活率明显高于H2 O2 处理组(P <0 .0 1) ;而LDH漏出率则明显低于H2 O2 处理组(P <0 .0 5 )。结论:大豆异黄酮活性组分对H2 O2 诱导的PC12细胞损伤具有保护作用。     

电针对全麻围气管插管期血流动力学的影响

目的:观察电针内关等穴位对全麻围气管插管期血流动力学的影响.方法:选择全麻气管插管病人60例随机分成电针组(麻醉诱导前电针刺激内关、合谷、曲池、神门)和对照组各30例,两组病人均用咪唑安定、芬太尼、异丙酚、琥珀酰胆碱等全身麻醉药物诱导,光导喉镜明视下行气管插管;于麻醉诱导、插管期不同时点监测血流动力学各项指标的变化.结果:麻醉诱导期电针组血流动力学各项指标相对平稳,对照组则表现为显著下降(P＜0.01).气管插管过程中,电针组各项指标较麻醉诱导前有一定升高(P＜0.05),而对照组则呈现显著上升(P＜0.01).插管后5分钟两组各项指标恢复正常.结论:电针刺激内关等穴位可以稳定围插管期血流动力学变化,提高麻醉手术的安全性.     

补肾方含药血清促进PC12细胞增殖及其拮抗谷氨酸神经毒作用的研究

目的:运用中药血清药理学方法研究补肾复方含药血清(BS)促进体外培养的PC12细胞增殖及其拮抗谷氨酸兴奋性神经毒损伤的作用.方法:以MTT法观察BS对体外培养的PC12细胞活力的影响及其拮抗谷氨酸损伤的作用,采用流式细胞术观察BS对谷氨酸所诱导PC12细胞凋亡的影响.结果:BS含药血清可以增强PC12细胞活力,拮抗谷氨酸的兴奋性神经毒作用且在20%浓度时作用最强,并且能够抑制谷氨酸诱导的PC12细胞早期凋亡.结论:补肾方BS可能具有神经保护作用.