异氟醚对小鼠神经干细胞活力及内大麻素系统相关基因表达的影响

目的:探讨异氟醚对小鼠神经干细胞活力及内大麻素系统相关基因表达的影响。方法:给予体外培养的小鼠海马神经干细胞不同浓度异氟醚处理,实验分为对照组和异氟醚处理组(0.5ISO,1.0ISO),其中异氟醚组细胞分别给予0.5 MAC和1.0 MAC两个浓度的异氟醚处理2小时,对照组给予O_2处理2小时,随后检测细胞活力并提取细胞RNA检测其内源性大麻素受体1(Cannabinoid receptor1,CB1)、脂肪酰胺水解酶(Fatty acid amide hydrolase,FAAH)、单酰甘油脂肪酶(Monoacylglycerol lipase,MAGL)及二酰基甘油脂肪酶(Diacylglycerol lipase alpha,DAGLα)的mRNA表达的变化。结果:与对照组相比,(1)异氟醚处理明显抑制了体外培养神经干细胞的活力,且高浓度异氟醚抑制作用强于低浓度异氟醚;(2)异氟醚上调神经干细胞的内大麻素受体CB1 mRNA水平,且高浓度异氟醚作用强于低浓度异氟醚;(3)异氟醚促进神经干细胞FAAH和MAGL的mRNA表达而抑制DAGLα的mRNA表达,且高浓度异氟醚作用强于低浓度异氟醚。结论:异氟醚可能通过影响小鼠神经干细胞的内大麻素系统影响神经干细胞的活力。     

高压氧预处理对大鼠脑缺血再灌注损伤的保护作用及对其海马BDNF和GDNF基因表达的影响

目的:探讨高压氧预处理(Hyperbaric oxygen preconditioning, HBO-PC)对大鼠脑缺血再灌注损伤的保护作用及对其海马脑源性神经营养因子(brain-derived neurotrophic factor, BDNF)、胶质细胞源性神经营养因子(glialcellline-derivedneurotrophicfactor,GDNF)基因表达的影响。方法:将32只SD雄性大鼠随机分为对照组(Sham组)、高压氧对照组(HBO组)、模型组(MCAO组)、高压氧预处理+模型组(HBO+MCAO组),对HBO组和HBO+MCAO组连续给予高压氧预处理5天,随后对MCAO组和HBO+MCAO组进行右侧颈内动脉栓线术,建立大脑中动脉闭塞(middle cerebral artery occlusion, MCAO)模型,其他两组行假手术,于术后第7天对各组大鼠进行Morris水迷宫行为学检测和神经功能评分,检测结束后处死大鼠,进行神经功能缺损评分及氯化三苯基四氮唑(2,3,5-triphenyltetrazolium chloride, TTC)染色;通过蛋白免疫印迹法(Western Blot)检测大鼠海马组织BDNF和GDNF的基因表达情况。结果:(1)神经功能评分提示:Sham组和HBO组均未出现神经功能障碍,MCAO组大鼠出现明显的神经功能障碍,MCAO+HBO组神经功能评分明显高于MCAO组(P0.05)。(2)TTC检测提示:Sham组和HBO组脑组织损伤一侧均未出现梗死灶,MCAO组出现较大的梗死面积比(25.45±8.75)%,MCAO+HBO组的梗死面积比(18.84±10.55)显著小于MCAO组,差异具有统计学意义(P 0.05)。(3)Western Blot检测显示:MCAO组BDNF与GDNF基因表达水平显著低于Sham组和HBO组,差异具有统计学意义(P 0.05),而MCAO+HBO组可以逆转这一效应,差异具有统计学意义(P 0.05)。结论:高压氧预处理可以通过调节BDNF、GDNF基因表达,改善MCAO模型大鼠神经功能和认知水平,发挥神经保护作用。     

头孢曲松神经保护作用的研究

目的:探讨头孢曲松通过抑炎通路发挥神经保护作用的机制。方法:45只雄性SD大鼠,随机分为3组(n=15),预处理组在大鼠大脑中动脉阻断(MCAO)前5 d每日给予腹腔注射头孢曲松缓冲液(200 mg/kg),观察局灶性脑缺血2 h再灌注24 h后,各组间大鼠神经行为学评分、脑梗死容积变化、小胶质细胞和IL-1β的数量变化。结果:再灌注24 h后,头孢曲松预处理组可改善大鼠神经行为学评分和脑梗死面积(P<0.05),小胶质细胞活化数量减少(P<0.05),ELISA检测IL-1β分泌数量有显著下降趋势,但无统计学差异(P=0.18)。结论:头孢曲松可以部分抑制小胶质细胞活化,减少IL-1β释放发挥神经保护作用。     

不同剂量异氟醚对中年小鼠认知功能及海马MBP和pNF-H表达的影响

目的:探讨异氟醚对中年小鼠认知功能及海马髓磷脂碱性蛋白(MBP, myelin basic protein)和磷酸化神经丝重亚单位(pNF-H,phosphorylated neurofilament heavy chain)表达的影响。方法:给予中年小鼠不同浓度的异氟醚处理,实验分为对照组和异氟醚处理组(0.5ISO,1.0ISO,1.5ISO),其中异氟醚组小鼠细胞分别给予0.5 MAC,1.0 MAC和1.5 MAC三个浓度的异氟醚处理4小时,对照组给予O_2处理4小时,随后通过水迷宫测试检测其学习记忆能力变化,通过免疫荧光检测海马形态结构及髓鞘相关蛋白MBP和pNF-H表达变化。结果:与对照组相比,(1)类临床浓度的异氟醚处理不影响中年小鼠的自发运动能力(总运动距离:sham:7275.17±1732.58; 0.5ISO:8057.58±1732.58; 1.0ISO:7540.98±1401.61; 1.5ISO:8243.79±1257.65;运动速度:sham:116.75±22.35; 0.5ISO:135.45±32.84; 1.0ISO:130.16±21.38; 1.5ISO:142.31±20.58),但1.0 MAC和1.5 MAC的异氟醚处理明显降低了中年小鼠在水迷宫目标象限的活动时间百分比(sham:58.62±13.70; 0.5ISO:48.92±7.22; 1.0ISO:31.23±13.16; 1.5ISO:30.29±15.76)(P 0.05),且高浓度异氟醚作用强于低浓度异氟醚;(2) 1.0 MAC和1.5 MAC的异氟醚处理明显下调了海马的MBP和p NF-H表达(MBP:sham:60.48±8.20; 0.5ISO:56.69±7.86; 1.0ISO:40.15±4.50; 1.5ISO:31.66±5.46; pNF-H:sham:62.23±9.45; 0.5ISO:55.47±6.98; 1.0ISO:40.16±6.97; 1.5ISO:30.94±5.89)(P 0.05),造成了小鼠海马髓鞘结构损伤,且高浓度损伤强于低浓度。结论:异氟醚可能通过下调中年小鼠海马MBP和pNF-H表达,破坏海马髓鞘完整性而损伤小鼠的学习认知能力。     

利多卡因对异氟醚麻醉后大鼠海马组织炎症及认知功能的影响

目的:研究利多卡因对异氟醚麻醉后大鼠海马区炎症因子、神经活性物质及认知功能的影响。方法:60只老龄SD大鼠随机分为3组:异氟醚组、利多卡因+异氟醚组、对照组各20只,建立大鼠吸入麻醉模型。利多卡因+异氟醚组给予静脉注射利多卡因,其他组给予生理盐水作为对照。麻醉结束后24 h Morris水迷宫实验评价大鼠认知功能,ELISA法检测大鼠海马组织炎症因子和神经活性物质。结果:与对照组相比,异氟醚组Morris水迷宫逃避潜伏期延长(P0.05),平台象限停留时间及穿越平台次数减少(P0.05),海马组织TNF-α、IL-6、IL-1β水平升高(P0.05),NT-3、NGF、BDNF水平降低(P0.05)。利多卡因明显缩短异氟醚麻醉大鼠的逃避潜伏期并增加其平台象限停留时间及穿越平台次数(P0.05),降低海马组织炎症水平(P0.05),升高神经活性物质水平(P0.05)。结论:利多卡因可明显缓解异氟醚麻醉后大鼠海马组织的炎症反应并升高海马组织神经活性物质水平,改善认知功能障碍。     

天麻素对脑缺血再灌注小鼠海马新生神经元的保护作用

目的:探讨不同剂量天麻素(Gastrodin,GAS)对缺血再灌注模型小鼠海马新生神经元的保护作用及其可能机制。方法:将50只C57BL/6小鼠随机分为假手术组(Sham)、模型组(MCAO+Vehicle)、模型+天麻素低剂量(10 mg/kg)组(MCAO+GAS(L)),模型+天麻素中剂量(50 mg/kg)组(MCAO+GAS(M)),模型+天麻素高剂量(100 mg/kg)组(MCAO+GAS(H))。除Sham组接受假手术外(皮肤切开,分离颈动脉),分别对MCAO组及MCAO+GAS各组行右侧颈内动脉栓线术,造成并保持大脑中动脉闭塞(MCAO)1 h。术后,Sham组和MCAO组即刻腹腔注射生理盐水(0.1 m L/kg),MCAO+GAS各组注射不同剂量天麻素,每24小时重复给药1次,连续7天。最后一次注射24 h后,对各组小鼠的神经功能进行评分,之后处死动物取脑组织,通过HE、免疫荧光染色以及Western Blot观察和比较各组小鼠海马形态学和DCX的表达水平。结果:(1)术后第7天,MCAO+Vehicle组小鼠神经功能评分(3.2±0.63)显著高于假手术组、MCAO+GAS(M)(1.8±0.63)和MCAO+GAS(H)组(P0.05)。(2)术后第7天,与假手术组相比较,MCAO+vehicle组海马颗粒细胞排列不规则,核稍大且固缩深染,齿状回部有较多空洞;与MCAO+vehicle组比较,MCAO+GAS(H)组海马空洞样改变减少,细胞排列较整齐,胞膜较完整,核结构较清晰。(3)术后第7天,与假手术组相比较,DCX染色阳性细胞数显著减少,而MCAO+GAS(M)组DCX染色阳性细胞数(183±64.5)和MCAO+GAS(H)组DCX染色阳性细胞数(195±93.68)显著高于MCAO+Vehicle组。MCAO+Vehicle组海马的DCX表达水平显著低于假手术组及MCAO+GAS(M)组和GAS(H)组(P0.01)。结论:天麻素可能通过上调海马DCX的表达水平,调节海马神经发生,进而对缺血性脑卒中后再灌注发挥神经保护作用。     

产前应激对成年子代大鼠缺血性卒中后细胞凋亡的影响

目的:研究产前应激对雄性子代大鼠大脑中动脉缺血/再灌注后神经功能的影响。方法:SD孕鼠随机进行产前应激处理(孕期每日3次限制活动)和无产前应激处理,并对其雄性子代大鼠采用线栓法制备大脑中动脉局灶性脑缺血(MCAO)模型,共分为假手术组、产前应激+假手术组、MCAO模型组、产前应激+MCAO组(n=10)。于再灌注24 h后进行神经功能评分,并检测脑梗死面积、神经细胞凋亡情况和凋亡相关蛋白表达。结果:产前应激+MCAO组子代大鼠神经功能评分、脑梗死面积百分比、TUNEL阳性细胞、半胱氨酸天冬氨酸蛋白酶3(Caspase3)和活化的Caspase 3蛋白表达均较MCAO组显著增加(P0.05),而B淋巴细胞瘤-2(Bcl-2)蛋白表达较MCAO组减少(P0.05)。结论:产前应激可能通过促进子代大鼠脑缺血/再灌注后神经细胞凋亡,加重神经功能缺损。     

七氟醚预处理对缺血再灌注损伤大鼠的神经保护作用及机制研究

目的:探讨七氟醚对大鼠缺血再灌注损伤的保护作用。方法:选取48只体重260 g±10 g的健康雄性SD大鼠,随机分为假手术组、损伤组及七氟醚组。假手术组大鼠分离右侧颈总动脉及颈外动脉结扎,不进入颅内置入线栓。损伤组吸入100%纯氧60min之后对右颈内动脉采用尼龙线线栓法制备大脑中动脉阻闭模型(MCAO),七氟醚组吸入2.5%七氟醚(2.5%七氟醚及97.5%氧气)60 min后再行MCAO模型制备。3组大鼠缺血2 h后,进行再灌注24 h。观察三组大鼠的神经功能评分及脑组织TNF-α和IL-1β蛋白水平。结果:假手术组大鼠神经功能评分中位数为18分;损伤组评分中位数为7分;七氟醚组大鼠评分中位数为13分,三组大鼠的评分分布差异具有统计学意义(x2=35.784,P=0.000)。各组大鼠脑组织TNF-α和IL-1β蛋白总体水平差异具有统计学意义(F=15.201,P=0.00;F=26.879,P=0.000)。进一步两两比较后,损伤组TNF-α和IL-1β蛋白水平高于七氟醚组及假手术组,七氟醚组高于假手术组,但远低于损伤组水平,P=0.000。结论:七氟醚对大鼠神经功能有一定保护作用,其机制可能与其影响大鼠脑组织TNF-α及IL-1β蛋白水平,减轻脑缺血再灌注后组织炎症反应有关。     

异氟烷预处理对电磁脉冲辐射所致脑损伤的保护作用研究

目的:探讨异氟烷预处理对电磁脉冲辐射所致脑损伤的保护作用。方法:选取成年雄性SD大鼠48只,采用随机数字表法,将其随机分为4组(n=12),分别为:假辐照组(CON组)、电磁辐照组(EMP组)、异氟烷预处理组(IP组)和异氟烷预处理+电磁辐照组(IP+EMP组)。EMP组场强为400 KV/m,脉冲为200次,连续辐照3天;IP组吸入2.0%异氟醚2h;IP+EMP组吸入2.0%异氟醚2 h,24 h后制备EMP损伤模型。于辐照后24 h处死大鼠,每组随机抽取3只大鼠,取脑组织,采用ELISA法检测大鼠海马IL-6和TNF-α的表达变化;尼氏染色法观察大鼠海马区神经元的凋亡;采用Western blot法检测大鼠海马区BDNF蛋白的表达情况;采用免疫荧光法检测大鼠海马区BDNF细胞水平的表达。结果:与CON组比较,EMP组、IP组、IP+EMP组的IL-6和TNF-α的表达增高,尼氏小体减少,BDNF蛋白及细胞水平的表达均下调(P0.05);与EMP组比较,IP组和IP+EMP组IL-6和TNF-α的表达降低,尼氏小体增多,BDNF蛋白及细胞水平的表达上调(P0.05)。结论:异氟烷预处理可减轻电磁脉冲辐射所致脑损伤,其机制可能与减轻大鼠炎症反应有关。     

七氟醚预处理对大鼠脑缺血再灌注损伤的改善机制

目的:探究七氟醚预处理对大鼠脑缺血再灌注损伤的影响,以及转化生长因子-β2(TGF-β2)/Smad3信号通路的活化情况。方法:将50只SD大鼠随机分为5组(n=10):假手术组、模型组、七氟醚预处理组、吡非尼酮组和七氟醚预处理+吡非尼酮组。通过右颈内动脉(ICA)缝线结扎方法制备脑缺血再灌注(I/R)损伤模型。建模前1h,七氟醚组大鼠吸入2.0%七氟醚1h,吡非尼酮组大鼠腹膜内注射200 mg/kg的TGF-β2抑制剂吡非尼酮,七氟醚+吡非尼酮组大鼠同时应用两种药物处理。再灌注24 h后,通过Zea-Longa五级评分法评价大鼠神经功能缺损评分,处死大鼠并测量梗死体积。通过苏木精-伊红(HE)染色和Nissl染色评价脑组织损伤程度。TdT介导的dUTP缺口末端标记法(TUNEL)分析细胞凋亡。免疫荧光染色和Western blot检测TGF-β2、Smad3、血管内皮生长因子-A(VEGF-A)和CD34的表达情况。结果:七氟醚预处理明显降低了大鼠的脑梗塞面积和神经功能缺损评分。七氟醚预处理抑制了大鼠大脑皮质和海马CA1区的神经元凋亡。七氟醚预处理上调了TGF-β2、VEGF-A和CD34的表达,以及Smad3的磷酸化水平。TGF-β2抑制剂吡非尼酮处理均可减弱七氟醚的脑保护作用并抑制TGF-β2、VEGF-A和CD34的表达和Smad3的磷酸化。结论:七氟醚预处理通过激活TGF-β2/Smad3信号通路来减轻I/R损伤大鼠的脑损伤。     

Scurvy in capybaras bred in captivity in Argentine

In order to determine if the absence of vitamin C in the diet of capybaras (Hydrochoerus hydrochaeris) causes scurvy, a group of seven young individuals were fed food pellets without ascorbic acid, while another group of eight individuals received the same food with 1 g of ascorbic acid per animal per day. Animals in the first group developed signs of scurvy-like gingivitis, breaking of the incisors and death of one animal. Clinical signs appeared between 25 and 104 days from the beginning of the trial in all individuals. Growth rates of individuals deprived of vitamin C was considerably less than those observed in the control group. Deficiency of ascorbic acid had a severe effect on reproduction of another population of captive capybaras. We found that the decrease in ascorbic acid content in the diet affected pregnancy, especially during the first stages. The results obtained suggest that it is necessary to supply a suitable quantity of vitamin C in the diet of this species in captivity.     

Changes in lactate dehydrogenase activity in chicken tissues in hyperthyreosis in ontogenesis

The lactate dehydrogenase activity in reactions of lactate oxidation and synthesis was studied in subfractions of the chicken brain, heart and liver at the embryonal, early postembryonal and adult stages of development after thyroxine administration. It has been shown that during embryogenesis thyroxine predominantly enhanced the rate of lactate oxidation in the mitochondrial tissues. A marked increase in the lactate synthesis was found in cytoplasm of the adult chicken tissues. Specificity of enzyme activity alterations was detected in the chicken brain during ontogenesis after thyroxine administration.     

Role for dopamine in malonate-induced damage in vivo in striatum and in vitro in mesencephalic cultures

Defects in mitochondrial energy metabolism have been implicated in the pathology of several neurodegenerative disorders. In addition, the reactive metabolites generated from the metabolism and oxidation of the neurotransmitter dopamine (DA) are thought to contribute to the damage to neurons of the basal ganglia. We have previously demonstrated that infusions of the metabolic inhibitor malonate into the striata of mice or rats produce degeneration of DA nerve terminals. In the present studies, we demonstrate that an intrastriatal infusion of malonate induces a substantial increase in DA efflux in awake, behaving mice as measured by in vivo microdialysis. Furthermore, pretreatment of mice with tetrabenazine (TBZ) or the TBZ analogue Ro 4-1284 (Ro-4), compounds that reversibly inhibit the vesicular storage of DA, attenuates the malonate-induced DA efflux as well as the damage to DA nerve terminals. Consistent with these findings, the damage to both DA and GABA neurons in mesencephalic cultures by malonate exposure was attenuated by pretreatment with TBZ or Ro-4. Treatment with these compounds did not affect the formation of free radicals or the inhibition of oxidative phosphorylation resulting from malonate exposure alone. Our data suggest that DA plays an important role in the neurotoxicity produced by malonate. These findings provide direct evidence that inhibition of succinate dehydrogenase causes an increase in extracellular DA levels and indicate that bioenergetic defects may contribute to the pathogenesis of chronic neurodegenerative diseases through a mechanism involving DA.     

我国葫芦科植物离体培养研究进展

葫芦科植物包括多种瓜类蔬菜,对其进行离体培养研究具有重要的理论和实践意义。综述了国内在葫芦科植物器官培养、体细胞胚胎发生、花药培养、原生质体培养和体细胞杂交及离体遗传转化等方面取得的研究进展,并对葫芦科植物离体培养、遗传转化与育种的前景作了展望。