应激预处理对应激大鼠心肌的影响

目的通过建立应激预处理适应动物模型,探讨应激预处理对应激大鼠心肌的影响。方法利用持续束缚建立应激预处理适应动物模型,采用高效液相检测血浆儿茶酚胺;ELLISA法检测血浆皮质醇换算成皮质酮含量;生物化学法测定心肌LDH、a-HBDH和CK-MB含量。结果①预处理组大鼠经过应激后,糖皮质激素的分泌水平明显低于应激组;②预处理组大鼠经过应激后,儿茶酚胺的分泌水平明显低于应激组;③预处理组大鼠应激后,血浆LDH、a-HBDH、CK-MB测定明显弱于应激组。结论应激预处理能够明显降低应激所造成的心肌损伤。     

棉籽总黄酮在大鼠慢性应激模型中的抗抑郁活性及其对海马神经营养通路的影响

目的探讨棉籽总黄酮(代号CTN-T)的抗抑郁作用及其可能机理。方法连续15d以每日1次的频率给予大鼠一系列不可预知的应激刺激以建立慢性复合应激模型,每次应激刺激前给予CTN-T(50或100mg.kg-1,ig)或地昔帕明(10mg.kg-1,ip)。采用Videomex-V运动图像分析系统观察大鼠敞箱自发活动行为,ELISA法检测血清皮质酮含量,Western印迹法检测海马脑源性神经营养因子(BDNF)、磷酸化cAMP反应元件结合蛋白(pCREB)、磷酸化细胞外信号调节激酶(pERK1/2)蛋白表达水平的变化。结果慢性复合应激15d后,大鼠自发活动显著减少,血清皮质酮含量显著升高。海马BDNF,pCREB和pERK1/2蛋白表达显著下调。每次应激刺激前给予CTN-T或地昔帕明可逆转上述变化。结论CTN-T在大鼠慢性应激模型上具有抗抑郁作用,其作用机制可能与上调海马BDNF相关的信号传导通路活性,改善神经营养和神经可塑性有关。     

联合应激法建立单纯心理应激动物实验模型的研究

目的 应用联合应激法建立单纯心理应激动物实验模型.方法 连续给予心理应激(PS)组小鼠隔离应激30 d,并每天随机给予捕食应激或社会失败应激1次,末次应激后第2天进行旷场实验,断颈取血,通过酶联免疫吸附试验(ELISA)检测血清中促肾上腺皮质激素释放激素(CRH)、促肾上腺皮质激素(ACTH)、皮质醇(CORT)水平,并与正常对照(NC)组进行比较.结果 (1)PS组经联合心理应激后,5 min旷场活动明显减少(P=0.000);(2)PS组与NC组比较,血清中CRH、ACTH及CORT水平均明显升高,差异有统计学意义(P=0.000).结论 通过联合应激法,可建立一种可靠的单纯心理应激动物实验模型.     

四逆散有效组分拮抗空瓶刺激所致大鼠慢性情绪应激的作用

目的:探讨四逆散有效组分拮抗慢性情绪应激大鼠的作用。方法:利用连续21 d空瓶刺激所致大鼠慢性情绪应激模型,观察四逆散有效组分(450 mg/kg/day,连续21 d)对模型大鼠的体重、行为学、血清皮质酮含量及大鼠海马组织病变的影响。结果:四逆散有效组分能够有效拮抗空瓶刺激诱导的大鼠慢性情绪应激反应,表现为大鼠体重明显升高、攻击和探究行为减少、修饰行为增加、皮质酮含量降低、改善情绪应激导致的海马损伤。结论:四逆散有效组分可能是通过抑制皮质酮的含量升高,减少海马损伤而发挥其拮抗慢性情绪应激的作用。     

复合应激源诱发大鼠实验性高血压效果观察

目的利用电刺激加噪音为复合应激源作慢性应激刺激大鼠,诱发形成稳定的实验性高血压模型。方法采用低频、低压交流电电击大鼠足底并同时给予噪音实施应激刺激28d,测定其血压和心率的变化,并与对照组进行比较。结果应激组大鼠与正常对照组大鼠比较,血压显著升高;心率明显增快。结论以电刺激加噪音刺激作为复合应激源作为慢性应激刺激的方法,在诱发动物实验性高血压中是可行的。     

慢性复合应激诱发高血压动物模型的制备

目的:应用多重刺激手段,模拟上班白领族遭受的常见复合应激因素,制备慢性应激性高血压(SIH)大鼠模型,为进一步探讨SIH的发生、发展机制奠定基础.方法:健康成年Wistar大鼠30只随机分为传统模型组(n=10)、自建模型组(n=10)及正常对照组(n=10).传统模型组接受足底电击结合工业噪声复合刺激,自建模型组应用不规则震荡、不良音乐、部分睡眠剥夺复合刺激法.正常对照组不接受应激刺激.建模时间为4周,在应激刺激0、7、14、21、28日(分别以D0、D1、D7、D14、D21、D28表示)测定各组收缩压及心率.第二十九日颈动脉插管取血4 mL,分离血浆,酶联免疫吸附法(ELISA)法检测血浆血管紧张素Ⅱ(AngⅡ)及皮质醇水平,高效液相色谱(HPLC)法测定血浆儿茶酚胺含量.结果:传统模型组收缩压在应激刺激第七天较基础值上升约15 mmHg,在第十四天达高峰(140.6±4.3)mmHg,而后略下降,但仍维持在高水平直至第二十八天;自建模型组SBP变化趋势与传统模型组类似,但上升时间及达高峰时间均晚1周;在观察期,正常对照组收缩压平稳.传统模型组及自建模型组心率在应激刺激1周后即开始增加,自第二周开始维持心率在较高水平,与正常对照组比较,差异有统计学意义(P<0.05).传统模型组及自建模型组血浆血管紧张素Ⅱ、去甲肾上腺素、肾上腺素、皮质醇水平均显著高于正常对照组,差异均有统计学意义(P<0.05).结论:应用不规则震荡、不良音乐、部分睡眠剥夺复合刺激法可成功诱发实验大鼠产生SIH,成功制备SIH大鼠模型.     

花椒多酚类化合物对慢性应激抑郁大鼠的治疗作用机制研究

目的探讨花椒多酚类化合物(ZPPC)对慢性应激抑郁大鼠的治疗作用及可能机制。方法将40只慢性应激模型大鼠随机均分为应激模型组,低、中、高剂量ZPPC(50,100,200 mg/kg)组和丙咪嗪(10 mg/kg)组,另设正常对照组(n=8),测定各组大鼠的开野和强迫游泳行为,酶联免疫吸附试验双抗体夹心法测定大鼠血清皮质酮质量浓度和白细胞介素1β(IL-1β)水平,并测定各组大鼠肾上腺皮质厚度。结果与应激模型组比较,低、中、高剂量的ZPPC能明显增加应激大鼠在开野箱中的活动性和探究次数,剂量依赖性地减少其在强迫游泳中的行为绝望时间,并且还能降低血清皮质酮质量浓度和IL-1β水平(均P<0.05,P<0.01,P<0.001),同时降低肾上腺皮质厚度(均P<0.01)。结论 ZPPC可以改善慢性应激引起的抑郁样行为,作用机制可能与其增强免疫功能、保护肾上腺结构和功能有关。     

2种小鼠应激模型致模式分离损伤特点及米非司酮和普萘洛尔对足底电击模型小鼠模式分离的干预作用比较

目的 比较 2 种小鼠应激模型致模式分离损伤的特点及米非司酮和普萘洛尔的干预作用。方法(1) 分别采用足底电击或 sc注射给予皮质酮(50和 100 mg·kg^-1)2种方式制备小鼠应激模型,采用物体识别范式评价应激后第 1,8 和 15 天小鼠时间与空间模式分离能力;(2) 在足底电击模型上,C57BL/6J 小鼠按体重和自主活动性随机分为正常对照组、足底电击组、足底电击+米非司酮(70 mg·kg^-1)组、足底电击+普萘洛尔(20 mg·kg^-1)组和足底电击+米非司酮+普萘洛尔组。每次足底电击应激前 30 min ip 给药,观察小鼠的时间和空间模式分离能力。结果 (1) 在足底电击模型上,与正常对照组相比,造模后第 1天模型组小鼠的时间辨别指数及空间辨别指数均显著降低(P<0.05);第 8天仅空间辨别指数明显降低(P<0.01);第 15天时间及空间辨别指数均无明显差异。在 sc 注射皮质酮模型中,与正常对照组比较,模型组小鼠仅于造模后第 1 天表现出空间辨别指数显著降低(P<0.05),造模...     

小鼠脑室内注射人参皂苷代谢物对脑室内注射应激诱导的血皮质酮水平变化的抑制

下丘脑-垂体-肾上腺轴(HPA)是与应激最密切相关的系统之一。曾发现脑室内注射人参总皂苷和人参皂苷Rc可降低因脑室内注射应激导致的血浆皮质酮水平的升高，2成分腹腔给药也可降低免疫应激引起的血浆皮质酮水平的升高，但人参皂苷主要肠内细胞代谢物20-O-β-D-吡喃葡糖基-20(5)-原人参萜二醇(化合物K)、     

减压特号对慢性应激大鼠的抗抑郁作用及机制研究

目的探讨中药复方减压特号（Jianyatehao,JYTH）对慢性应激大鼠抑郁样行为的改善作用及其对肾上腺结构功能、免疫系统和单胺递质系统的影响。方法大鼠随机分为正常对照组、应激模型组、JYTH（低、中、高1剂量组及丙咪嗪组。建立大鼠慢性应激模型,测定应激大鼠的开野行为和糖水消耗量。ELISA法测定大鼠血清皮质酮、IL-1β和IL-6的水平,HPLC测定应激大鼠不同脑区的单胺递质水平。结果与慢性应激组相比,JYTH低、中、高剂量组明显增加大鼠在开野箱中的活动性,并增加其对糖水的偏爱性,明显降低血清皮质酮、IL-1β和IL-6的水平,明显增加不同脑区单胺递质含量。结论JYTH可以改善慢性应激引起的抑郁样行为,其作用机制可能与降低血清皮质酮水平、保护肾上腺结构完整、增强免疫功能和提高脑内单胺递质含量有关。     

Behavioural changes after different stress paradigms: prepulse inhibition increased after physical, but not emotional stress.

Physical (PS) and emotional (ES) stress have opposite long-term effects on open field behaviour, i.e., response to novelty. PS induced a long-term reduction in locomotor activity, while ES increased it. Additionally, sensitivity to rewarding stimuli was differentially affected by PS and ES. Whether the stress effects were specific for locomotor activity and reward or if these two stress treatments also have differential effects on other behaviours and brain functions is not known. In the present study, temperature regulation, sensory gating, learning capacity, locomotor activity and coping style were examined. PS consisted of a repeated mild foot shock treatment, which the ES animals witnessed. The tests pose additional challenges, to which all groups can respond differently depending on their previous experience. All tests were performed several days after the last stress treatment. Stress effects were specifically observed on locomotor activity, startle response and prepulse inhibition (PPI). The PS animals showed a potentiated inhibition of the startle when a prepulse (PPI) was used, although the initial startle response was already significantly lower than that of controls. ES animals did not differ from controls on PPI and startle. Additionally PS animals showed an initial decrease in activity, which turned into an increase when the tests continued. ES showed a constant increase in activity compared to controls. Stress effects on the tests for other brain processes and behaviour were not found. In addition, PS animals appeared to be less sensitive to the dopamine agonist apomorphine than control animal. In summary, physical and emotional stress induce differential changes on locomotor activity, startle response and PPI. Underlying mechanisms explaining the differences in stress effects are discussed, i.e., the role of the mesolimbic dopamine system and opioid systems.     

银杏叶提取物对大鼠肺成纤维细胞表达CTGF和α-SMA的影响

目的观察银杏叶提取物(GBE)对大鼠肺成纤维细胞表达CTGF和α-SMA的影响。方法大鼠气管内一次性滴注博来霉素制备肺纤维化模型,原代培养大鼠肺成纤维细胞,分为4组:对照组、GBE 25,50,100 mg/L组,共培养24 h,采用免疫细胞化学法和流式细胞技术检测GBE对各组细胞表达CTGF和α-SMA的影响。结果与对照组比较,50,100 mg/L组细胞表达CTGF和α-SMA依次降低,各组间比较有统计学意义(P<0.05)。结论银杏叶提取物能部分抑制大鼠肺成纤维细胞的表型转化。     

Effects of Ginkgo biloba on corticosterone stress responses after inescapable shock exposure in the rat

Extracts from the leaves of the Ginkgo biloba tree (GBE) are found to be clinically effective in neuroprotection, cerebral and cardiovascular function and cognitive processing. Recent animal findings suggest that GBE also may improve stress adaptation and prevent learned helplessness, as evidenced by its reduction of behavioral acquisition deficits of active avoidance after inescapable shock exposure. In the present report, the effects of two doses of GBE were studied on corticosterone stress responses and acquisition of active avoidance after inescapable shock exposure. Forty-eight rats were divided into three groups: either receiving a daily dose of 50 mg/kg or 150 mg/kg of GBE (containing 24% flavonoid and 6% terpenoid) or vehicle for 2 weeks. After 2 weeks of administration, animals were trained for active-avoidance acquisition following inescapable shock exposure (stress induction) or nonshock exposure (nonstress). Administration of 150 mg/kg but not of 50 mg/kg of GBE significantly prevented a corticosterone stress response after inescapable shock exposure (P<.0001) without any beneficial behavioral effect on active avoidance. Repeated administration of GBE particularly improves biological adaptation to noxious stimuli without beneficial behavioral consequences. Present findings do not support previous claims about the benefits of G. biloba on improving behavioral stress adaptation and acquisition of active avoidance and on reducing behavioral deficits indicative of "learned helplessness."     

Action of the novel antioxidants 4GBE43 and 2BBE43 against lipid peroxidation.

The action and the effect of the newly synthesized compounds 4GBE43 [N-(1,2-diethyltetrahydro-1H-pyrazol-4-yl)-4-[(2E)-3,7-diethyl-2,6-octadienyl] oxybenzamide] and 2BBE43 [2-(benzyloxy)-N-(1,2-diethyltetrahydro-1H-pyrazol-4-yl)benzamide] against lipid peroxidation were studied. 4GBE43 and 2BBE43 quenched the ESR signal of diphenylpicrylhydrazyl (DPPH), suggesting that 4GBE43 and 2BBE43 act as scavengers of free radicals and that each compound quenched 6 free radical molecules. These compounds suppressed the oxidation of methyl linoleate emulsions and soybean phosphatidylcholine liposomes by a free radical initiator, suggesting that these compounds quench the lipid peroxyl radical. 4GBE43 and 2BBE43 also suppressed the spontaneous oxidation of rat brain homogenates. The inhibitory effect of 2BBE43 was of the same order of magnitude (IC50) as that of probucol. The IC50 of 4GBE43 was on the same order of magnitude as that of alpha-tocopherol. However, 4GBE43 at 10(-4)-10(-5) M completely inhibited peroxidation, showing it to be more effective than alpha-tocopherol. These results suggest that 4GBE43 and 2BBE43 act as antioxidants by quenching the lipid peroxyl radical.     

Intestinal absorption and presystemic elimination of various chemical constituents present in GBE50 extract, a standardized extract of Ginkgo biloba leaves

The nature and level of systemic exposure to the active herbal constituents will profoundly affect their effects at action sites, which is fundamental in understanding their roles in the overall beneficial effects of a herbal medicine. The objective of this study is to gain a full picture of the systemic exposure to various putatively active ginkgo constituents after p.o. administration of GBE50 extract, a standardized extract of Ginkgo biloba leaves, to rats and understanding of the relevant mechanisms governing the intestinal absorption and presystemic elimination. To define the ginkgo compounds to be studied, literature informatics-guided chemical profiling revealed that GBE50 extract contained 72 ginkgo constituents, including terpene lactones, flavonols, flavones, an isoflavone, biflavones, flavanols, and carboxylic acids, at levels ranging from 0.01 to 55.3 mg/g. Among the ginkgo constituent groups were the terpene lactones and the flavonols that were significantly measurable in plasma after p.o. administration of GBE50 extract to rats. The intestinal absorption of terpene lactones appeared to be dictated by their intermediate membrane permeability, while the influences of MDR-1- and MRP-2- mediated intestinal efflux and the presystemic metabolism and biliary excretion might be relatively limited. Because of their deglycosylation absent in the small intestine and relatively slow presystemic elimination, many intact flavonol glycosides appeared in the rat plasma albeit with a limited extent of absorption. Colonic deglycosylation of the flavonol glycosides occurred and the glucuronides of flavonol aglycones were also measured in the plasma. Although some biflavones also had relatively high abundance in GBE50 extract, these ginkgo constituents were not measured in the rat plasma because of their poor solubility and poor permeability that hindered the intestinal absorption. The levels of the remaining ginkgo constituents in GBE50 extract were too low to be measured in the rat plasma. The current study enabled us to better understand the nature of systemic exposure to ginkgo compounds after p.o. administration of GBE50 extract and to more precisely implement multicomponent PK study of the extract.     

体外扩散池法评价银杏酮酯磷脂复合物体外透过性能研究

目的 用体外扩散池法评价银杏酮酯制备成磷脂复合物后经大鼠肠透过性能的变化.方法 选取大鼠不同区段肠包括十二指肠、空肠、回肠和结肠,用体外扩散池法选出银杏酮酯透过性能的最佳区段肠后,再对银杏酮酯原料、银杏酮酯磷脂复合物和杏灵颗粒在最佳区段肠中进行透过性能的比较,用高效液相色谱法测定银杏酮酯中的黄酮醇苷在接收池中的累积透过量,表观渗透系数（Papp）作为指标评价银杏酮酯制备成磷脂复合物后的肠透过性能的变化.结果 银杏酮酯在十二指肠中的透过性最好,其次是空肠,由于一般药物在十二指肠停留的时间较短,所以选择空肠作为最佳区段肠,对银杏酮酯原料和银杏酮酯磷脂复合物的透过性能进行比较,结果银杏酮酯磷脂复合物的表观渗透系数高于银杏酮酯原料和杏灵颗粒.结论 用体外扩散池法对其初步评价,银杏酮酯原料制备成磷脂复合物后,体外肠透过性能比银杏酮酯原料和杏灵颗粒有显著提高,为提高体内生物利用度提供了有利依据.     

银杏酮酯口服自微乳化给药系统的制备

研究制备银杏酮酯口服自微乳化给药系统。采用平衡溶解度方法筛选乳化剂与助乳化剂; 采用伪三元相图法制备微乳; 采用正交法优化处方组成; 并考察自微乳化制剂的乳化效率、溶出度、稳定性与药动学研究等。结果表明, 由肉豆蔻酸异丙酯IPM、聚氧乙烯蓖麻油Cremophor EL、丙二醇与银杏酮酯组成的自微乳化给药系统遇水可自发形成粒径为20～50 nm的稳定微乳。自微乳化给药系统的乳化效率与溶出快, 且制剂稳定性高, 能提高生物利用度。制备的银杏酮酯口服自微乳化给药系统稳定有效。     

Systemic and cerebral exposure to and pharmacokinetics of flavonols and terpene lactones after dosing standardized Ginkgo biloba leaf extracts to rats via different routes of administration

BACKGROUND AND PURPOSE

Flavonols and terpene lactones are putatively responsible for the properties of Ginkgo biloba leaf extracts that relate to prevention and treatment of cardiovascular disease and cerebral insufficiency. Here, we characterized rat systemic and cerebral exposure to these ginkgo compounds after dosing, as well as the compounds’ pharmacokinetics.

EXPERIMENTAL APPROACH

Rats received single or multiple doses of ShuXueNing injection (prepared from GBE50 for intravenous administration) or GBE50 (a standardized extract of G. biloba leaves for oral administration). Brain delivery of the ginkgo compounds was assessed with microdialysis. Various rat samples were analysed using liquid chromatography/mass spectrometry.

KEY RESULTS

Slow terminal elimination features of the flavonols counterbalanced the influence of poor oral bioavailability on their systemic exposure levels, which also resulted in significant accumulation of the compounds in plasma during the subchronic treatment with ShuXueNing injection and GBE50. Unlike the flavonols, the terpene lactones had poor enterohepatic circulation due to their rapid renal excretion and unknown metabolism. The flavonol glycosides occurred as major forms in plasma after dosing with ShuXueNing injection, while the flavonol aglycone conjugates were predominant in plasma after dosing with GBE50. Cerebral exposure was negligible for the flavonols and low for the terpene lactones.

CONCLUSION AND IMPLICATIONS

Unlike the significant systemic exposure levels, the levels of cerebral exposure to the flavonols and terpene lactones are low. The elimination kinetic differences between the two classes of ginkgo compounds influence their relative systemic exposure levels. The information gained is relevant to linking ginkgo administration to the medicinal effects.     

银杏叶提取物GBE50对培养细胞内胆固醇代谢的影响

目的研究银杏叶提取物GBE50对不同培养细胞内胆固醇含量的影响,及对HepG2细胞内胆固醇代谢相关基因HMGCR和SREBF2表达的调节。方法采用MTT法观察了GBE50对HepG2细胞生长的影响,用胆固醇氧化酶终点法检测GBE50对培养细胞HepG2、HUVEC、SH-SY5Y总胆固醇含量的影响;用荧光实时定量PCR技术检测了药物处理后HMGCR和SREBF2基因表达水平在HepG2细胞中的改变。结果GBE50在不影响HepG2细胞的增殖的剂量下可不同程度降低培养细胞HepG2,HUVEC内总胆固醇含量。对HepG2细胞内总胆固醇的影响呈一定的剂量及时间-效应关系,同时可以调节其中HMGCR、SREBF2基因的表达。结论GBE50可有效降低部分培养细胞内总胆固醇的含量,部分胆固醇代谢相关基因表达量的改变可能是GBE50调节HepG2细胞内胆固醇水平的机制之一。     

Ginkgo biloba extract markedly induces pentoxyresorufin O-dealkylase activity in rats

We examined the effect of Ginkgo biloba extract (GBE) on hepatic drug-metabolizing enzymes, particularly cytochrome P450 (CYP), in rats. Rats were fed a GBE-containing diet or received GBE by intragastric gavage. The concentration of CYP and activity of various CYP enzymes in the liver were increased in a dose- and time-dependent manner. Significant increases in the concentration and activities of CYP enzymes were detected on day 1 of feeding of a 0.5% GBE diet and after administration of 10 mg GBE/kg body weight for 5 days by intragastric gavage. Among the CYP enzymes, the activity of pentoxyresorufin O-dealkylase (PROD), a CYP2B enzyme, was especially markedly increased. The induction of CYP2B enzyme by GBE was confirmed by Western blot analysis. Addition of GBE to a CYP assay system in vitro caused concentration-dependent inhibition of various CYP enzyme activities. The inhibition was more marked for the microsomal enzymes from GBE-treated rats than for those from control rats and more marked against PROD activity among the CYP enzymes tested. When the inhibition of various CYP enzymes activities by GBE in vitro was compared, no marked difference was observed between rat and human hepatic microsomal enzymes. These results indicate that excess intake of GBE induces CYP enzymes, particularly PROD, and may modify the efficacy of drugs taken simultaneously.