0.7 MPa氮氧混合气对中枢γ-氨基丁酸能神经功能的影响

目的 观察0.7 Mpa氮氧混合气对中枢γ-氨基丁酸(GABA)能神经活动的影响.方法 采用液体闪烁技术,检测了0.7 Mpa氮氧混合气作用下SK-N-SH神经细胞GABA释放与摄取情况及GABA受体亲和力的变化.并采用半定量RT-PCR检测了GABA受体的mRNA表达变化.结果 0.7MPa氮氧混合气作用下,SK-N-SH神经细胞释放GABA增强,摄取减少,GABA受体亲和力下降,GABA受体mRNA表达无明显变化.结论 0.7 Mpa氮氧混合气作用下,中枢GABA能神经功能减弱.     

0.7 Mpa高气压对大鼠脑突触体、神经细胞和神经胶质细胞释放及摄取γ-氨基丁酸的作用

目的研究0．7MPa（7ATA）氮氧混合气对大鼠纹状体、下丘脑、中脑和小脑突触体以及神经元和神经胶质细胞释放及摄取γ-氨基丁酸（GABA）的作用。方法同位素液体闪烁检测技术检测突触体和细胞释放标记GABA的量和摄取标记GABA的量。结果纹状体、下丘脑和中脑突触体释放GABA增加，小脑释放GABA无明显变化。纹状体、下丘脑、中脑和小脑突触体摄取GABA均增加。SKN-SH细胞释放和摄取GABA明显增加。C6细胞摄取GABA增加。结论0．7MPa氮氧混合气条件下GABA神经递质代谢加快，其抑制功能可能减弱。     

维甲酸对人乳腺癌细胞NIS基因表达和摄碘功能的影响

目的探讨9-顺-维甲酸（9-cis—RA）对人乳腺癌细胞钠／碘同向转运体（NIS）基因功能表达的影响。方法应用9-cis—RA和全反式维甲酸（ATRA）分别在不同浓度下对雌激素受体（ER）阳性的乳腺癌细胞（MCF-7）和ER阴性的乳腺癌细胞（MDA—MB-231）进行干预，于不同时间点提取细胞总RNA，通过半定量逆转录-聚合酶链反应（RT—PCR）检测乳腺癌细胞NIS mRNA表达水平的变化；在体外培养条件下研究RA刺激后乳腺癌细胞对放射性碘的摄取情况。结果9-cis—RA处理后，MCF-7细胞NIS mRNA表达增强，呈浓度依赖性（F=114．17，P〈0．001），在10^-6mol／L浓度下NIS mRNA的表达随时间上调，16h时达到最高，是对照组（0h）的8．2倍（q=8．32，P〈0．01），此后随时间逐渐下调；且9-cis—RA（10^-6mol／L，24h）的作用强于ATRA（t=6．572，P〈0．01）。MDA—MB-231基础状态下几乎无NIS表达，9-cis—RA刺激后可上调其表达（t=20．195，P〈0．001），但表达量（NIS／B—actin）远低于MCF-7（t=10．395，P〈0．001）。碘摄取实验表明，10^-6mol／L 9-cis—RA干预12h后，MCF-7细胞摄碘开始增加，干预24h时碘摄取达最大，是基础状态下的3．2倍，其摄碘能力可被KCl0。抑制。结论9-cis—RA能明显增强ER阳性的MCF-7细胞NIS基因的表达及摄碘功能。     

肝硬化大鼠Kupffer细胞血小板活化因子合成水平及其受体表达

目的研究肝硬化时Kupffer细胞血小板活化因子（PAF）生成水平及其受体表达的变化及意义。方法建立CCl4诱导的肝硬化模型,分离、培养Kupffer细胞,快速^3H—PAF液闪检测Kupffer细胞及其培养上清液内PAF水平,免疫组织化学染色检测PAF在Kupffer细胞内的分布情况,受体饱和结合实验和RT-PCR分析Kupffer细胞PAF结合能力及PAF受体mRNA表达水平。结果肝硬化大鼠Kupffer细胞合成与释放PAF明显增加,分别为对照组的1．48倍（P〈0．01）和2倍（P〈0．01）。免疫组化显示Kupffer细胞胞浆内PAF呈阳性表达。肝硬化大鼠的Kupffer细胞PAF结合能力Bmax明显升高（P〈0．01）,而受体亲和力Kd与对照组比较无明显变化。RT-PCR显示PAF受体mRNA表达明显增加（P〈0．05）。结论Kupffer细胞是肝硬化时PAF生成的一个重要来源,通过增加PAF合成和释放并上调PAF受体表达,Kupffer细胞参与肝硬化门脉高压的形成。     

肺型氧中毒小鼠肺组织巨噬细胞炎症蛋白-2 mRNA表达的改变

目的观察高压氧暴露后小鼠肺组织巨噬细胞炎症蛋白-2（macrophage inflammatory protein-2，MIP-2）mRNA表达的影响。方法40只健康C57BL/6雄性小鼠采用随机数字法分为5组：650 UPTD组、850 UPTD组、1100 UPTD组、高压常氧组和对照组。小鼠在密闭氧舱中吸入高压纯氧建立肺型氧中毒模型。对照组吸入空气，高压常氧组吸入氮氧混合气，氧分压与空气中氧分压相同。动物出舱后解剖取肺，肺组织用于病理检测和RT-PCR方法检测MIP-2 mRNA的表达。结果（1）高压氧暴露组与对照组相比，MIP-2 mRNA表达明显增高（P〈0．05）；（2）高压常氧组与对照组MIP-2 mRNA表达没有明显变化（P〉0．05）。结论随着高压氧暴露剂量的增加，MIP-2 mRNA的表达明显增多，并且炎症损伤也呈增加趋势。     

高压氧对沙鼠脑缺血海马神经细胞Ca2+-ATP酶活力的影响

目的探讨高压氧（HBO）作用后对脑缺血海马神经细胞Ca^2＋-ATP酶活力的影响。方法用蒙古种沙土鼠，采用双侧颈总动脉结扎制作前脑缺血模型，动物随机分为正常对照组、缺血再灌注组（夹闭双侧颈总动脉30min制作全脑缺血模型，随后放开动脉夹使再灌流80min）、0．1MPa纯氧组、0．25MPa高压氧组、0．25MPa常氧高氮组共5个组。采用定磷法测定海马神经细胞Ca^2＋-ATP酶活力。结果急性脑缺血再灌注后，Ca^2＋-ATP酶活力显著下降（P〈0．01），经0．1MPa纯氧和0．25MPa高压氧作用后，Ca^2＋-ATP酶活力均明显恢复，与急性脑缺血再灌注组相比，差异有统计学意义（P〈0．01），而且以0．25MPa高压氧组作用更为显著，0．25MPa常氧高氮组Ca^2＋．ATP酶活力无明显改变，结论高压氧可通过恢复Ca^2＋-ATP酶活力以恢复细胞内游离Ca^2＋浓度。     

11C-PD153035摄取与肿瘤EGFR表达水平相关性的研究

目的研究^11C4-（3-溴苯氨基）-6，7-双甲氧喹唑啉（PD153035）摄取与表皮生长因子受体（EGFR）表达水平之间的关系。方法在体外测定人乳腺癌细胞MDA—MB-468、MDA—MB-231和人肺腺癌细胞A549的EGFR表达水平以及对^11C—PD153035的摄取。分别建立裸鼠种植瘤模型，通过尾静脉注射^11C—PD153035后即刻行PET显像，用感兴趣区（ROI）法在注射后即刻及10，20，30，40，50和60min测定病灶／健侧前肢正常组织放射性计数（T／NT）比值。显像结束后立即处死动物，切除肿瘤，测量肿瘤内摄取的放射性。结果在体外肿瘤细胞对^11C—PD153035的摄取与肿瘤细胞EGFR表达水平明显相关（r^2=0．78，P=0．001）。在动物体内，TINT与肿瘤细胞的EGFR表达水平明显相关（r^2=0．65，P=0．004）。离体肿瘤组织对^11C—PD153035的摄取与肿瘤细胞的EGFR表达水平明显相关（r^2=0．64，P=0．005）。结论^11C-PD153035的摄取与肿瘤细胞的EGFR表达水平明显相关，EGFR的^11C—PD153035 PET显像有可能为肿瘤的诊断与治疗提供依据。     

高压氧对脊髓损伤大鼠脊髓组织中兴奋性氨基酸的影响

通过复制脊髓损伤（SCD模型，用常氧，高压氧（HBO），氮氧混合气，激素等分别处理各组大鼠后，取脊髓组织测兴奋性氨基酸（EAA，包括天冬氨酸Asp及谷氨酸Glu)含量，以探讨HBO治疗SCI的机制。结果显示，损伤后，大鼠脊髓组织中EAA（Glu)含量明显升高，经不同处理后，除氮氧混合气组外，Glu含量均有所下降，以0.25MPa HBO组和0.25MPa HOB 激素组下降最明显，与损伤组比较有显著性差异（P＜0．01），与正常对照组比较则无显著性差异；0.25MPa HBO组与0.1MPa HBO组比较及0.25MPaHBO激素组与激素组比较，均有显著性差异（P＜0．01）。提示HBO能通过减少组织中的EAA减轻SCI后的继发性损伤，恢复脊髓组织的功能，其中以0 .25MPa HBO和0.25MPa HBO并用激素治疗效果较佳。     

99Tcm-MAVGG-硝基咪唑硫嘌呤荷瘤小鼠乏氧显像

目的探讨有氧与乏氧条件下^99Tc^m-巯基乙酰基-缬氨酸-甘氨酸-甘氨酸（MAVGG）-硝基咪唑硫嘌呤在肿瘤细胞的摄取及其在荷瘤小鼠体内的生物学分布和显像特点。方法用^99Tc^m-标记双功能螯合剂MAVGG偶联的硝基咪唑硫嘌呤。体外测定有氧与乏氧条件下标记物在S180肉瘤细胞内的滞留率。观察荷瘤小鼠体内生物学分布及其γ显像。结果乏氧条件下标记物与S180肉瘤细胞结合5h后，在S180肉瘤细胞内的滞留率为0．59，高于有氧条件下的0．36。生物学分布显示肿瘤摄取率高，注射后3h肿瘤与肌肉和血液的摄取率比值分别为4．24和1．55。γ显像示肿瘤显影清晰。结论^99Tc^m-MAVGG-硝基咪唑硫嘌呤有望作为新的肿瘤乏氧显像剂。     

吲哚美辛对β淀粉样蛋白1-42刺激BV-2细胞产生一氧化氮的抑制作用

目的研究吲哚美辛对β淀粉样蛋白1-42（A-β1—42）刺激小胶质细胞（MG）释放一氧化氮（N0）的抑制作用。方法应用高度纯化的BV-2小胶质细胞作为体外小胶质细胞模型，应用不同浓度吲哚美辛（10^-9、10^-8、10^-7、10^-6、10^-5mol／L）与20μmol／L Aβ1—42单独或同时培养12h，测定细胞上清NO含量及细胞iNOS活性；RT-PCR法测定BV-2细胞iNOS mRNA的表达。结果吲哚美辛单独作用对BV-2细胞产生NO、iNOS活性及iNOS mRNA表达无明显作用。Aβ1—42可以刺激产生NO、提高细胞iNOS酶活性、增加iNOS mRNA表达，这些作用均可被吲哚美辛所抑制，吲哚美辛浓度为10^-7～10^-5mol／L时抑制作用较为明显。结论在体外吲哚美辛可以降低Aβ1—42介导的BV-2细胞iNOS活性及iNOS mRNA表达，从而减少NO的产生，上述抑制作用可能参与了吲哚美辛在AD治疗中的神经元保护机制。     

Recent neurochemical basis of inert gas narcosis and pressure effects.

Compressed air or a nitrogen-oxygen mixture produces from 0.3 MPa nitrogen narcosis. The traditional view was that anaesthesia or narcosis occurs when the volume of a hydrophobic site is caused to expand beyond a critical amount by the absorption of molecules of a narcotic gas. The observation of the pressure reversal effect on general anaesthesia has for a long time supported the lipid theory. However, recently, protein theories are in increasing consideration since results have been interpreted as evidence for a direct anaesthetic-protein interaction. The question is to know whether inert gases act by binding processes on proteins of neurotransmitter receptors. Compression with breathing mixtures where nitrogen is replaced by helium which has a low narcotic potency induces from 1 MPa, the high pressure nervous syndrome which is related to neurochemical disturbances including changes of the amino-acid and monoamine neurotransmissions. The use of narcotic gas (nitrogen or hydrogen) added to a helium-oxygen mixture, reduced some symptoms of the HPNS but also had some effects due to an additional effect of the narcotic potency of the gas. The researches performed at the level of basal ganglia of the rat brain and particularly the nigro-striatal pathway involved in the control of the motor, locomotor and cognitive functions, disrupted by narcosis or pressure, have indicated that GABAergic neurotransmission is implicated via GABAa receptors.     

Effects of NMDA administration in the substantia nigra pars compacta on the striatal dopamine release before and after repetitive exposures to nitrogen narcosis in rats.

Hyperbaric nitrogen-oxygen exposure developed in rats a decrement of the striatal dopamine release, which was reversed by repetitive exposures. This dopamine decrease could be the result of the antagonistic effect of nitrogen on NMDA receptors. The increment of the dopamine release, following repetitive exposures to nitrogen, could be attributed to a desensitisation of NMDA receptors to the effects of nitrogen. To test these hypotheses, male Sprague-Dawley rats were implanted with electrodes in the striatum to measure dopamine release by voltammetry and cannula in the substantia nigra pars compacta for NMDA injection. Free-moving rats were exposed up to 3MPa of nitrogen-oxygen mixture before and after 5 exposures to 1MPa. At the first exposure to 3MPa, the dopamine level decreased (-15%) but is counteracted by NMDA administration. In contrast, after repetitive exposure, the second exposure to 3MPa, induces a 10% dopamine increase. NMDA administration significantly potentiated this increase. Our results neither support the hypothesis of an antagonist effect of nitrogen on NMDA receptors at the first exposure, nor that of a NMDA receptor desensitization following repetitive exposures to hyperbaric nitrogen.     

Mammalian CNS barosensitivity: studied by brain-stem auditory-evoked potential in mice

High pressure nervous syndrome (HPNS) is an instinctive response of mammalian high-class nervous functions to increased hydrostatic pressure. Electrophysiological activity of mammalian central nervous system (CNS), including brainstem auditory-evoked potential (BAEP), has characteristic changes under pressure. Here we recorded BAEP of 63 mice exposed to 0-4.0 MPa. The results showed that interpeak latencies between wave I and wave IV (IPL1-4) and their changes under pressures (deltaIPL1-4) responded to increasing pressure in a biphase pattern, shortened under pressure from 0 to 0.7MPa, then prolonged later. There were significantly negative correlations between base IPL1-4s and deltaIPL1-4s (p < 0.01). Individual IPL1-4s were supposed to respond to increasing pressure in a relative steady pattern in accordance with its base IPL1-4s. Those with shorter-base IPL1-4 presented direct increases in IPL1-4. However, those with longer-base IPL1-4 had a decreased IPL1-4 under small to moderate pressure then rebounded later. Our results suggested that mammalian CNS functions were susceptible to small to moderate pressure, as well as a higher pressure than 1.0MPa. Mice, as a statistical mass, had an "optimum" pressure about 0.7MPa, rather than atmospheric pressure, referred as shortest IPL1-4s. An individual's response to high pressure might be relied on his base biological condition. Our results highlighted a new approach to investigate a practical strategy to medical selecting barotolerant candidates for deep divers. Diversity of individual susceptibility to hydrostatic pressure was under discussed. Underlying mechanisms of the "optimum" pressure for CNS function and its significance to neurophysiology remain open to further exploration.     

Effect of hyperoxia and increased environmental gas density on the contractile function of the right of the heart

Rheocardiography, phonocardiography, and electrocardiography were used to investigate right ventricle function of 16 test subjects exposed to various gas atmospheres under increased pressure. During short-term exposures the adverse effect of an increased pressure on the contractile function of the right ventricle grew in the following order: hyperoxia--normoxic nitrogen-oxygen atmosphere--compressed air.     

大鼠胸部严重创伤后早期下丘脑CRH表达的实验研究

目的 探讨大鼠胸部撞击伤应激反应中,下丘脑表达和分泌促肾上腺皮质激素释放激素(CRH)的变化规律及其反馈调节机制。方法 应用BIM-Ⅲ型多功能小型生物撞击机致伤动物,采用免疫组化和RT-PCR等技术,检测大鼠下丘脑CRH的分布及含量变化规律。分组：对照组、撞击伤后15、30、60、120、360、720分钟组、撞击伤处理组(用CRH1R特异性阻滞剂CP-154526处理)。结果 正常情况下,CRH少量分布于下丘脑室旁核和视上核;撞击伤后,室旁核和视上核的CRH染色明显增加;撞击伤后60分钟,下丘脑CRH mRNA含量明显增加,且呈逐渐增加的趋势,720分钟开始回落;用CP-154526处理的大鼠,撞击伤后,下丘脑CRH含量的增加明显减少。结论 在创伤性应激反应早期,CRH通过与下丘脑神经元CRH1R的结合,选择性地调节下丘脑神经元CRH基因的表达。     

Effect of antidepressant and narcoleptic drugs on N-isopropyl p-iodoamphetamine biodistribution in animals

N-isopropyl p-iodoamphetamine (IMP) demonstrates a high affinity for lung and brain during the first pass following intravenous injection. Its high brain affinity has been used to advantage for cerebral perfusion imaging, but the effects of drugs on IMP distribution could affect its utility. In this study, we determined the effects of the tricyclic antidepressant imipramine and the MAO inhibitors deprenyl and phenelzine on the biodistribution of IMP. We first determined the effect of loading dose and anesthesia on the biodistribution of IMP. In rats, biodistribution was not dependent on loading dose between 0.1 and 1.1 mg/kg. Anesthesia with thiopental and chloral hydrate depressed lung and brain IMP uptake. In rats, preloading doses of imipramine depressed lung uptake but did not result in increased brain IMP uptake; postloading doses of imipramine did not release IMP from the lung. In rabbits, simultaneous or postloading doses of imipramine resulted in release of IMP from the lung with an increase in brain activity. Both mixed A and B MAO inhibitors (phenelzine) and B selective MAO inhibitors (deprenyl) did not affect IMP distribution in rats. Based on the action of imipramine on IMP uptake and clearance in the lung, we postulate that IMP uptake and metabolism within the lung is related to the mixed function oxidase (MFO) system. As the lung is rich in the MFO system in humans, we would also predict from this study that IMP distribution in patients under antidepressant therapy would not be affected by either tricyclic or MAO inhibitor agents apart from the effect of these drugs on cerebral perfusion.     

甘氨酸对大鼠创伤性休克继发肝损伤的防护作用

目的 研究甘氨酸对大鼠创伤性休克后肝组织热休克蛋白70(HSP70)和TNF-αmRNA表达的影响,探讨其对大鼠创伤性休克继发肝损伤的可能保护机制.方法 建立创伤性休克动物模型,120只Wistar大鼠按随机数字表法分成3组:创伤性休克组(休克组)、甘氨酸治疗组(治疗组)和对照组.在复苏开始时,治疗组大鼠将甘氨酸按100 mg/kg溶于0.5 ml等渗盐水后经颈静脉输入,休克组输以同体积的等渗盐水.分别于复苏后3,6,12,24及48 h 5个时相点处死大鼠.采用RT-PCR法检测肝组织HSP70和TNF-α mRNA表达;观察肝组织病理改变并测定血清ALT和AST水平. 结果 休克组复苏后3 h肝组织HSPTO和TNF-αmRNA表达即增加,复苏后6 h达高峰,治疗组肝组织HSP70 mRNA表达于复苏后12 h达高峰.与休克组比较,治疗组各时相点肝组织TNF-α mRNA表达明显降低(P<0.05),HSP70 mRNA表达明显增强(P<0.05),血清ALT和AST明显降低(P<0.05),肝组织光镜下病理损害明显改善(P<0.05). 结论甘氨酸可能通过增强肝组织HSP70 mRNA表达及抑制TNF-α mRNA表达的途径降低创伤性休克后继发肝损伤的程度.