坐骨神经慢性挤压伤模型大鼠行为学及形态学变化

目的:观察大鼠坐骨神经慢性挤压伤模型所引起的行为学及病理形态学变化。方法:实验于2006-02/05在解放军军事医学科学院生物工程研究所完成。①SD大鼠24只,随机分为3组,坐骨神经结扎组12只制备右侧坐骨神经慢性挤压伤模型,正常对照组6只不干预,假手术组6只手术但不结扎,观察处理后42d内自发痛、触诱发痛、热刺激及冷刺激痛觉过敏等行为学变化。②SD大鼠54只,随机分为正常对照组、假手术组及坐骨神经结扎后3,7,14,21,28,35,42d组9组,处理同前,相应时间点处死大鼠观察坐骨神经和脊髓组织大体形态、苏木精-伊红染色和轴突髓鞘染色观察脊髓组织病理变化,电镜观察超微结构变化。结果:78只大鼠进入结果分析。①行为学变化:坐骨神经结扎组大鼠术后3d即出现明显的自发性疼痛,机械刺激痛阈值从术前的(17.33±5.42)g降至(3.28±1.37)g;热刺激爪退缩阈值从(12.13±2.37)s缩短至(10.43±1.65)s;冷刺激抬足次数从(3.50±1.09)次增加至(14.75±2.34)次。术后7￣14d这些阈值的变化逐渐达高峰,并持续至观察期结束(42d)。②坐骨神经结扎大鼠坐骨神经结扎部位及其远端轴突水肿,部分脱髓鞘。结论:大鼠坐骨神经慢性挤压伤模型可以产生明显的、稳定的自发性疼痛和诱发性疼痛等类似临床神经痛的症状和体征;其局部病理变化与症状相符。     

大鼠颈椎间盘退行性变后软骨细胞凋亡及形态学改变

背景椎间盘软骨终板是椎间盘营养渗透的主要途径,又是维持脊柱生物力学的重要结构之一.对其重要性的认识及相关研究日益深入,但对椎间盘退行性变的确切原因仍不清楚.目的动态观察大鼠颈部动静力失去平衡后颈椎间盘软骨细胞凋亡的形态学改变以及凋亡率.设计采用完全随机对照设计.地点和对象实验在上海中医药大学脊柱病研究所完成,对象为8月龄清洁级SD大鼠60只,雌雄各30只.干预将雌雄大鼠分别按随机数字表法分为3,5,7月对照组与模型组,每组10只,雌雄各5只.取大鼠颈背部正中纵向切口,切开皮肤后,充分游离各层肌肉,横向切断深群颈夹肌和头、颈、寰最长肌,完全切除颈髂肋肌与头半棘肌,然后再依次切断C2～C7棘上和棘间韧带,建立的动静力失衡性颈椎间盘退行性变模型.主要观察指标3,5,7月后椎间盘软骨细胞凋亡程度.结果退行性变椎间盘内有典型凋亡的软骨细胞.与对照组比较,各个模型组软骨细胞凋亡指数明显升高(P＜0.01);模型组间比较,TUNEL法5,7月软骨细胞凋亡指数分别为36.59±5.93和36 36±5.13较3月(27.73±4.12)明显升高(P＜0.01),流式细胞仪PI法5,7月细胞凋亡指数分别为37.56±3.82和28.02±3.48较3月(21.45±2.23)明显升高(P＜0.01).结论退行性变椎间盘软骨终板内软骨细胞凋亡数目增多,这可能是椎间盘退行性变的重要机制之一.     

Characterization of a pentylenetetrazol-like interoceptive stimulus produced by ethanol withdrawal

Rats were trained with food reinforcement to discriminate the anxiogenic drug pentylenetetrazol (PTZ, 20 mg/kg) from saline in a two-lever-choice task. In Experiment 1, ethanol, 8.25% w/v was given by gavage (7/day) for 4 days, with doses titrated to maintain moderate intoxication. After termination of ethanol, the rats exhibited mild overt signs of withdrawal and, in discrimination tests with saline as the test substance, they selected the PTZ lever, an effect reversed by ethanol, 2 g/kg, and by diazepam, 5 mg/kg. In Experiment 2, rats drank a nutritionally complete liquid diet containing ethanol, 4.5% w/v, for 1 week. They became tolerant to the intoxicating effect of ethanol, and blood ethanol concentration mounted with continued dosing. On termination of chronic ethanol, rats selected the PTZ lever before the onset of overt physical signs of withdrawal, and both measures returned to base line within 3 days. In Experiment 3 the percentage of rats selecting the PTZ lever after termination of ethanol depended upon the dose (up to 12.5 g/kg) and duration (up to a ceiling effect by 3 days) of ethanol administered chronically. These results indicate that a PTZ-like stimulus produced interoceptively can be demonstrated in the rat as an objective measure of ethanol withdrawal. This paradigm may provide insight into the symptom of anxiety associated with ethanol withdrawal.     

The convulsive and electroencephalographic changes produced by nonpeptidic delta-opioid agonists in rats: comparison with pentylenetetrazol

delta-Opioid agonists produce convulsions and antidepressant-like effects in rats. It has been suggested that the antidepressant-like effects are produced through a convulsant mechanism of action either through overt convulsions or nonconvulsive seizures. This study evaluated the convulsive and seizurogenic effects of nonpeptidic delta-opioid agonists at doses that previously were reported to produce antidepressant-like effects. In addition, delta-opioid agonist-induced electroencephalographic (EEG) and behavioral changes were compared with those produced by the chemical convulsant pentylenetetrazol (PTZ). For these studies, EEG changes were recorded using a telemetry system before and after injections of the delta-opioid agonists [(+)-4-[(alphaR)-alpha-[(2S,5R)-2,5-dimethyl-4-(2-propenyl)-1-piperazinyl]-(3-methoxyphenyl)methyl]-N,N-diethylbenz (SNC80) and [(+)-4-[alpha(R)-alpha-[(2S,5R)-2,5-dimethyl-4-(2-propenyl)-1-piperazinyl]-(3-hydroxyphenyl)methyl]-N,N-diethylbenzamide [(+)-BW373U86]. Acute administration of nonpeptidic delta-opioid agonists produced bilateral ictal and paroxysmal spike and/or sharp wave discharges. delta-Opioid agonists produced brief changes in EEG recordings, and tolerance rapidly developed to these effects; however, PTZ produced longer-lasting EEG changes that were exacerbated after repeated administration. Studies with antiepileptic drugs demonstrated that compounds used to treat absence epilepsy blocked the convulsive effects of nonpeptidic delta-opioid agonists. Overall, these data suggest that delta-opioid agonist-induced EEG changes are not required for the antidepressant-like effects of these compounds and that neural circuitry involved in absence epilepsy may be related to delta-opioid agonist-induced convulsions. In terms of therapeutic development, these data suggest that it may be possible to develop delta-opioid agonists devoid of convulsive properties.     

坐骨神经损伤后相应脊髓前角运动神经元的形态学变化

目的探讨坐骨神经损伤与修复过程中相应脊髓前角外侧核运动神经元的形态学变化,并对神经元尼氏染色法的应用价值进行评估。方法采用硅胶管套接切断的大鼠坐骨神经模型,应用焦油紫染色、甲苯胺蓝染色和硫堇染色等3种尼氏法对伤后7、14、30d脊髓前角运动神经元进行形态学观察。结果应用3种染色方法均观察到坐骨神经伤侧脊髓前角外侧核大、中型运动神经元的形态结构和存活率与对照侧有明显差别。与对照侧比较,伤后7d伤侧脊髓神经元数目减少,存活率降低;伤后14d和伤后30d,尤其是伤后30d,伤侧脊髓神经元数目减少更显著,存活率下降更明显,有些神经元轮廓不清且尼氏体模糊。结论随着大鼠坐骨神经损伤时间的延长,其相应脊髓前角运动神经元的损伤程度逐渐增加,尤其是伤后30d退变非常明显。焦油紫染色方法是显示神经元尼氏体及反映神经元生活状态的简捷有效的方法。     

电针内关穴对心肌缺血再灌注损伤大鼠心肌能量代谢及组织形态学的影响

目的:观察电针内关穴后缺血再灌注损伤大鼠心肌能量代谢及组织形态学变化,探讨针刺对缺血再灌注损伤大鼠的心肌保护作用。方法:实验于2003-10/2004-02在湖南中医药大学、湘雅医学院完成。实验分组:将50只大鼠完全随机分为5组,每组10只。即假手术组、模型组、电针内关组、电针神门组、电针合谷组。实验干预:①假手术组:开胸、穿线、不结扎,观察实验过程120 min。②模型组:开胸、穿线20 min、结扎40 min,松扎再灌注60 min。③电针内关组:开胸、穿线,电针内关20 min后,结扎40 min,再灌注60 min,于再灌注开始时再次电针内关20 min。④电针神门组:处理同电针内关组,电针穴位为神门。⑤电针合谷组:处理同电针内关组,电针穴位为合谷。穴位定位与电针参数:穴位定位:内关穴位于大鼠腕横纹正中上5 mm处,神门穴位于大鼠腕横纹尺侧处,合谷穴位于大鼠第一、二掌骨之间中点处,针刺深度约5 mm,造模成功后分别针刺大鼠双侧上述3穴,直刺穿皮达筋间,捻转1 min后,接电子针疗仪,疏密波刺激(疏波30 Hz,密波100 Hz),以前肢出现轻微颤动为准,持续时间为20 min。实验结束后颈动脉取血5 mL,摘取心脏检测相关指标。实验评估:①应用高效液相色谱法测定三磷酸腺苷、二磷酸腺苷、一磷酸腺苷和腺苷含量。②光学显微镜观察缺血再灌注损伤心肌病理形态学的变化。结果:50只大鼠均进入结果分析。①血清三磷酸腺苷含量:假手术组最高,模型组最低。电针内关组、电针神门组高于模型组[(0.33±0.14),(0.074±0.021),(0.045±0.015)mg/L,P<0.01,P<0.05],电针合谷组与模型组比较,差异无显著性(P>0.05)。②血清中二磷酸腺苷、一磷酸腺苷、腺苷含量:假手术组最低,模型组最高,电针内关组低于模型组[(0.110±0.065),(0.20±0.10)mg/L;(0.160±0.055),(0.28±0.11)mg/L;(0.045±0.015),(0.11±0.039)mg/L;P<0.05,P<0.01],电针神门组、电针合谷组与电针内关组比较,二磷酸腺苷含量差异不显著(P>0.05),一磷酸腺苷和腺苷差异非常显著(P<0.01)。③假手术组肌纤维整齐,肌丝及肌小节结构清晰可见,线粒体丰富,正常,未见水肿及空泡变;其次为电针内关组,可见肌纤维正常走向,少量线粒体空泡变,肌丝无明显坏死、溶解。模型组的心肌修复情况最差,表现为心肌肌丝溶解、坏死,肌丝走向紊乱,细胞核浓缩,染色质靠边,线粒体水肿,肌浆网扩张。电针神门组,可见部分标本心肌水肿,间质出血,其中1只可见心肌细胞部分坏死,炎性细胞浸润。电针合谷组,部分标本可见心肌水肿,间质出血,其中2只可见心肌坏死,炎性细胞浸润。结论:电针内关穴能明显改善缺血再灌注损伤大鼠心肌的能量代谢,促进心肌组织的修复。     

大鼠弥漫性轴突损伤后脑血管微循环障碍的超微结构特征与动态变化

目的研究大鼠弥漫性轴突损伤(DAI)后脑微血管超微结构特征与动态变化规律,以及与神经元超微结构变化的关系。方法SD成年大鼠24只(对照组3只,损伤组21只)。采用自制头颅旋转致伤装置,将损伤组大鼠头颅在冠状面绕脑组织中心逆时针旋转90°造成剪力伤,于伤后2、6、12、24、36、72、240h分批处死大鼠制作脑切片,行镀银及HE染色,在光镜及电镜下观察微血管与神经元的形态学变化。结果大鼠致伤后均出现意识丧失,2只在10min内死亡,肉眼可见蛛网膜下腔出血,其余存活大鼠于不同时相点光镜下均可见不同程度的轴突肿胀、断裂、轴索球形成,神经细胞核固缩,微血栓形成,微血管内皮细胞增生,管周间隙增大;电镜下可见不同程度的神经元胞体肿胀,线粒体空泡样改变,髓鞘板层结构消失。上述形态学改变在伤后12h达高峰。结论大鼠单纯性DAI早期就可见脑微血管结构破坏、微血栓形成、血管内皮细胞肿胀等微循环障碍表现,其高峰位于伤后12h,并以脑皮层部位表现最为明显,这种改变与轴突损伤的发生过程非同步。     

大鼠脑淋巴引流阻断后脑形态学和皮质诱发电位的改变

目的：观察分析脑淋巴引流阻断对脑形态和功能的影响。方法：实验于2003-01／08在泰山医学院脑微循环研究所完成。实验动物选择雄性健康成年Wistar大鼠64只。49只大鼠用于脑淋巴引流对脑形态学的影响实验，随机分成3组；大体观察组14只；光镜观察组21只和电镜观察组14只。每组又分为脑淋巴引流阻断亚组和假手术对照亚组。16只动物用于脑淋巴引流阻断对皮质诱发电位影响的观察，随机分成两组，假手术对照组6只，脑淋巴引流阻断组10只。脑淋巴引流阻断亚组通过摘除颈浅和颈深淋巴结造成脑淋巴引流障碍，假手术对照组不结扎淋巴管和摘除淋巴结，通过大体，光镜及电镜观察不同时间（淋巴引流阻断1，2。3，5，7，10，15d）脑结构变化以及皮质诱发电位潜伏期的改变。结果：64只大鼠在实验过程中无死亡，均进入结果分析，无脱失值。①在脑淋巴引流阻断大鼠，大体观察见脑表面苍白、饱满、脑沟变浅窄、脑回变宽平，光镜下组织间隙增宽，液体郁滞，神经元变性、坏死、并有大量吞噬细胞浸润，形成“卫星现象”，电镜下神经元肿胀，线粒体等亚细胞结构变化明显。②与假手术对照组比较，脑淋巴引流阻断后第5天至第7天皮质诱发电位潜伏期明显延长[（6．28&;#177;0.23），（6．9&;#177;0．348）ms，P〈0．011；（6．23&;#177;0．22），（7．12&;#177;0．20）ms；P〈0．01]。结论：脑淋巴引流阻断对脑形态结构有重要影响，脑淋巴引流的阻断引起脑内感觉冲动传导异常，皮质诱发电位潜伏期明显延长。皮质诱发电位检查简便易行，可作为淋巴引流障碍性脑损伤的一项重要指标。     

大鼠脑淋巴引流阻断后脑形态学和皮质诱发电位的改变

目的:观察分析脑淋巴引流阻断对脑形态和功能的影响。方法:实验于2003-01/08在泰山医学院脑微循环研究所完成。实验动物选择雄性健康成年Wistar大鼠64只。49只大鼠用于脑淋巴引流对脑形态学的影响实验,随机分成3组;大体观察组14只;光镜观察组21只和电镜观察组14只。每组又分为脑淋巴引流阻断亚组和假手术对照亚组。16只动物用于脑淋巴引流阻断对皮质诱发电位影响的观察,随机分成两组,假手术对照组6只,脑淋巴引流阻断组10只。脑淋巴引流阻断亚组通过摘除颈浅和颈深淋巴结造成脑淋巴引流障碍,假手术对照组不结扎淋巴管和摘除淋巴结,通过大体,光镜及电镜观察不同时间(淋巴引流阻断1,2,3,5,7,10,15d)脑结构变化以及皮质诱发电位潜伏期的改变。结果:64只大鼠在实验过程中无死亡,均进入结果分析,无脱失值。①在脑淋巴引流阻断大鼠,大体观察见脑表面苍白、饱满、脑沟变浅窄、脑回变宽平,光镜下组织间隙增宽,液体郁滞,神经元变性、坏死、并有大量吞噬细胞浸润,形成“卫星现象”,电镜下神经元肿胀,线粒体等亚细胞结构变化明显。②与假手术对照组比较,脑淋巴引流阻断后第5天至第7天皮质诱发电位潜伏期明显延长[(6.28±0.23),(6.97±0.348)ms,P<0.01];(6.23±0.22),(7.12±0.20)ms;P<0.01]。结论:脑淋巴引流阻断对脑形态结构有重要影响,脑淋巴引流的阻断引起脑内感觉冲动传导异常,皮质诱发电位潜伏期明显延长。皮质诱发电位检查简便易行,可作为淋巴引流障碍性脑损伤的一项重要指标。     

Lymphocyte DNA alteration by sub-chronic ethanol intake in alcohol-preferring rats

BACKGROUND: Excessive alcohol consumption has been correlated with a higher susceptibility to infections among humans. Chromosome aberrations and other parameters have been suggested as useful biomarkers in assessing genetic damage due to ethanol intake. METHODS: Genetically selected alcohol-preferring rats were given water, 10% ethanol and water or 10% ethanol alone for 3 months as fluid to drink. Food was available ad libitum for the entire period. At the end of the sub-chronic treatment their blood and liver were collected. All blood cells were counted and both lymphocytes and hepatocytes of all three groups were tested with the Comet assay to determine whether any DNA damage had occurred. RESULTS: Only lymphocytes showed DNA damage, with differences among groups. The group that had only ethanol to drink showed greater lymphocyte DNA damage than the ethanol/water and water alone groups. On the other hand, hepatocyte DNA did not show any signs of damage. CONCLUSIONS: Ten weeks of sub-chronic ethanol treatment produces small but significant damage to lymphocytes but not to hepatocytes, a result which confirms the observations of previous authors, and extends them even to a strain of rats genetically selected for high ethanol intake.     

Hormonal influences in the development of the hypermetabolic state of the liver produced by chronic administration of ethanol.

Chronic administration of ethanol to rats, either in liquid diets as the only source of food or by gastric intubation while the animals are fed ad libitum, leads to the development of a hypermetabolic state of the liver. This hypermetabolic condition of the liver can be observed independently of the feeding state of the animals. The calorigenic effects produced by ethanol in the liver, as measured in liver slices, could be reproduced by a single large dose of epinephrine. Oxygen consumption by liver slices of animals given a 2-mg/kg dose of epinephrine bitartrate increased by 40 to 50 percent. In these livers all the extra oxygen consumption, but not the basal respiration, could be abolished by ouabain, an inhibitor of the sodium pump. Dinitrophenol did not affect the respiratory rate in the liver of epinephrine-treated animals while markedly increasing that in controls. In the liver of treated animals, the activatory effect of dinitrophenol could be recovered in the presence of ouabain. The calorigenic effect of epinephrine in the liver was found to be completely abolished by phentolamine (alpha adrenergic blocker) but was not modified by DL-propranolol (beta adrenergic blocker). Also, the calorigenic effects produced by epinephrine could not be seen in thyroidectomized animals or by incubating the liver slices in a calcium-free medium. Thyroidectomy and administration of phentolamine markedly reduced and adrenalectomy completely abolished the hypermetabolic state produced in the liver of rats by chronic administration of ethanol.     

坐骨神经损伤与修复过程中相应脊髓神经元变化的形态学观察

目的探讨坐骨神经损伤与再生修复过程中相应脊髓前角运动神经元的形态学变化和嗅被膜细胞(OECs)对神经元的保护作用。方法采用硅胶管套接切断的大鼠坐骨神经实验模型,将30只大鼠随机分为两组,治疗组硅胶管内注射OECs悬液,对照组注射生理盐水(SAL),应用尼氏法对术后7d、14d、30dSAL组与OECs组脊髓前角运动神经元进行形态学观察,比较两组同类神经元的存活率。结果OECs组治疗侧脊髓前角外侧核大、中型运动神经元的形态结构和存活率与对照组有明显差别。术后7d,OECs组治疗侧神经元数目较SAL组伤侧丢失减少,存活率上升。术后14d和30d,OECs组治疗侧神经元数目较SAL组伤侧明显增加,存活率明显升高,大多数神经元轮廓清楚,尼氏体清晰。结论OECs能减少坐骨神经损伤后相应脊髓前角运动神经元的退行性变。     

Prefrontal hemodynamic changes produced by anodal direct current stimulation

Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique that has been investigated for the treatment of many neurological or neuropsychiatric disorders. Its main effect is to modulate the cortical excitability depending on the polarity of the current applied. However, understanding the mechanisms by which these modulations are induced and persist is still an open question. A possible marker indicating a change in cortical activity is the subsequent variation in regional blood flow and metabolism. These variations can be effectively monitored using functional near-infrared spectroscopy (fNIRS), which offers a noninvasive and portable measure of regional blood oxygenation state in cortical tissue. We studied healthy volunteers at rest and evaluated the changes in cortical oxygenation related to tDCS using fNIRS. Subjects were tested after active stimulation (12 subjects) and sham stimulation (10 subjects). Electrodes were applied at two prefrontal locations; stimulation lasted 10 min and fNIRS data were then collected for 20 min. The anodal stimulation induced a significant increase in oxyhemoglobin (HbO₂) concentration compared to sham stimulation. Additionally, the effect of active 10-min tDCS was localized in time and lasted up to 8–10 min after the end of the stimulation. The cathodal stimulation manifested instead a negligible effect. The changes induced by tDCS on HbO₂, as captured by fNIRS, agreed with the results of previous studies. Taken together, these results help clarify the mechanisms underlying the regional alterations induced by tDCS and validate the use of fNIRS as a possible noninvasive method to monitor the neuromodulation effect of tDCS.