THE PPAR ACTIVATOR DOCOSAHEXAENOIC ACID PREVENTS ACETAMINOPHEN HEPATOTOXICITY IN MALE CD-1 MICE

Acetaminophen (APAP)-induced hepatocellular necrosis can be prevented by treatment with peroxisome proliferators. This protection is associated with lowered protein arylation and glutathione depletion in mice. Peroxisome proliferators have been shown to activate nuclear receptors. These receptors, termed peroxisome proliferator activated receptors (PPARs), can also be activated by free fatty acids. This study was designed to determine if treatment with the PPAR activator docosahexaenoic acid (DHA) would also lower APAP toxicity. Male CD-1 mice received 250 mg DHA/kg or 500 mg clofibrate (CFB)/kg, ip, for 5 d. Controls received corn oil vehicle, ip. After overnight fasting, mice received 800 mg APAP/kg, po. At 24 h after APAP, hepatotoxicity was evident in control mice by elevated plasma sorbitol dehydrogenase activity (SDH) and histologic evidence of hepatic degeneration and necrosis. As expected, CFB pretreatment significantly decreased this. Similarly, DHA protected against APAP-induced hepatotoxicity at 24 h after challenge. However, treatment with DHA did not increase hepatic glutathione prior to APAP, as previously shown with CFB. Interestingly, DHA did not increase palmitoyl coenzyme A (CoA) oxidase activity or other biochemical parameters associated with peroxisome proliferation after 5 d of treatment at 250 mg/kg. No significant alterations in microsomal APAP glucuronidation or cytochrome P-450-mediated bioactivation were detected either. Collectively, these results show that DHA also prevents APAP-induced hepatotoxicity at 24 h after challenge. However, the association between resistance against APAP-induced liver injury, PPAR activation, and peroxisome proliferation is not clearly understood.     

醋氨酚对小鼠肝脏毒性的作用研究

小鼠一次性腹腔注射ＡＰ１００ｍｇ／ｋｇ、１３０ｍｇ／ｋｇ３小时后，ＳＧＰＴ、ＳＧＳＴ活性及ＬＴＧ、ＭＤＡ含量明显增加，肝微粒体ＧＳＴ活性及肝ＧＳＨ含量明显下降，且呈剂量依赖性。电镜观察，肝细胞超微结构线粒体固缩，小而不规则，模糊不清；ＲＥＲ和ＳＥＲ数量明显减少。     

黄褐毛忍冬皂甙对对乙酰氨基酚致小鼠肝脏毒性的保护作用

黄褐毛忍冬皂甙对对乙酰氨基酚致小鼠肝脏毒性的保护作用时京珍，刘耕陶（贵阳贵州省中医研究所５５０００２；中国医学科学院药物研究所１０００５０）我们已报道黄褐毛忍冬总皂甙对实验性肝损伤有保护作用［１］。经进一步实验发现其中的两种成分，即Ｈ和Ｓ均为保肝作用...     

慢性吗啡处理加强可卡因-苯丙胺调节转录肽mRNA在大鼠下丘脑的表达

目的··:观察可卡因 -苯丙胺调节转录肽 (CART)mRNAs在慢性吗啡处理后大鼠的下丘脑中表达的变化。方法·· :采用PT -PCR克隆CART基因 ,用原位杂交观察慢性吗啡依赖大鼠下丘脑中CARTmRNAs的表达。结果··:在视上核 (SON)和室旁核 (PVN) ,正常组的CARTmRNAs阳性细胞数分别为44.2±s14.3和85.3±s34.6 ,慢性吗啡处理组分别为63.8±s18.2和118.5±s55.0 ;纳洛酮可阻断慢性吗啡处理引起的CARTmRNAs阳性细胞数的增加,与吗啡依赖组相比分别减少34.0 %和58.6 %。结论·· :CART可能参与吗啡依赖的形成;由于中枢CART的增加可明显抑制动物的进食行为 ,降低动物的体重 ,因此下丘脑CARTmRNA的增加可能与吗啡依赖形成过程中进食行为的减少和体重的降低有关     

甘草类黄酮对四氯化碳致小鼠急性肝损伤的影响

甘草类黄酮(GF)是从甘草根中提得。本文结果表明,预先ig GF 200,400,600mg·kg^-1·d^-1×2d能显著降低CCl₄所致血清谷丙转氨酶,乳酸脱氢酶活性的升高以及肝内丙二醛含量的增加,其作用呈剂量依赖性。GF可减轻CCl₄所致的肝脏坏死,但对血清内酶的活性没有抑制作用,也不减少正常小鼠血清中酶的活性。GF的肝保护作用可能与其抗脂质过氧化作用有关。     

EFFECTS OF LEAD ON THE MALE REPRODUCTIVE SYSTEM IN MICE

The effect of environmental lead on the male reproductive system has been a major area of concern for several years. Lead toxicity to the male reproductive system of sexually mature male CF-1 mice was investigated by administering two concentrations of lead (0.25% and 0.5%) via drinking water for 6 wk. The low lead dose significantly reduced the number of sperm within the epididymis, while the high dose reduced both the sperm count and percentage of motile sperm and increased the percentage of abnormal sperm within the epididymis. There was no significant effect on testis weight; however, the high-dose treatment significantly decreased the epididymis and seminal vesicle weights as well as overall body weight gain. Plasma luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone (T) levels were not affected by lead administration indicating that in adult male CF-1 mice, lead targets testicular spermatogenesis and sperm within the epididymis to produce reproductive toxicity rather than acting at other sites within the hypothalamic-pituitary-testicular axis.     

乙酰胡椒乙胺对扑热息痛肝脏毒性的保护作用

目的：研究乙酰胡椒乙胺(piperoethyl acetyl amine, PAA)对扑热息痛(acetaminophen, AP)肝脏毒性的保护作用及其机制。方法：小鼠ig PAA后ip AP, 检测小鼠肝脏的损害程度,高效液相法检测血中AP含量,检测小鼠肝细胞色素P-450含量。结果：PAA明显降低AP所致的小鼠血清转氨酶升高,减轻肝脏病理损害,阻止肝内谷胱甘肽下降,增加肝细胞色素P-450含量,血中AP浓度明显降低。结论：PAA对AP中毒小鼠有明显肝保护作用。     

INCREASED RESISTANCE TO ACETAMINOPHEN-INDUCED HEPATOTOXICITY IN RETROVIRUS-INFECTED MICE

In this research we examined the influence of chronic retrovirus infection on the hepatic metabolism of a model substrate, acetaminophen (APAP), and its induced liver injury in mice inoculated with LP-BM5 murine leukemia viruses. Female C57BL/6 mice at 15–17 wks after LP-BM5 retrovirus inoculation and age-matched control animals were used in the studies. APAP treatment (300 mg kg⁻¹, p.o.) resulted in moderate to severe centrilobular necrosis in control animals, with the necrotic area accounting for 40–60% of the total area. In contrast, the APAP-treated (300 mg kg⁻¹, p.o.) infected animals exhibited mild zonal necrosis with the necrotic area accounting for 1–6% of the total area. In the same study, a statistically significant higher percentage of APAP glucuronide and a lower percentage of unchanged APAP were recovered from the urine of the LP-BM5-inoculated animals than from that of controls. No statistically significant differences between infected and uninfected animals in the urinary recovery of APAP sulfate, APAP cysteine, or APAP mercapturate were observed. The formation of APAP metabolites and APAP-associated biochemical changes were also determined from liver slice preparation to avoid in vivo complicating factors. Consistently more significant depletion of the intracellular glutathione levels and K⁺ content were observed in slices from the uninfected animals at high concentrations of APAP (1 and 2 mM) than in slices from the retrovirus-infected animals. The differences in APAP-associated biochemical changes were accompanied by a 1·4–1·5-fold increase in the formation of APAP glucuronide, sulfate, and glutathione metabolites in slices prepared from animals inoculated with LP-BM5. We concluded that, based on histological examination and hepatic biochemical measurements, the retrovirus-infected animals were more resistant to APAP-induced liver injury. This could be due, in part, to alterations in the detoxification and activation metabolic pathways of APAP.     

五味子对扑热息痛肝脏毒性的保护作用

五味子果仁乙醇提取物(五仁醇)及其有效成分之一五味子醇乙(醇乙),预先24h给药能显著降低大剂量扑热息痛(400mg/kg)肝中毒所致的小鼠死亡率,并防止肝内谷胱甘肽(GSH)的耗竭,增强肝微粒体代谢扑热息痛的速度,血中扑热息痛含量下降。从这些结果推测,五仁醇和醇乙的抗扑热息痛肝脏毒性作用可能是通过对肝微粒体细胞色素P-450的诱导作用,调整肝微粒体对扑热息痛代谢的途径,减少毒性代谢产物的生成量。醇乙是五味子对抗扑热息痛肝脏毒性的主要有效成分。     

POSSIBLE ROLE OF GLUTATHIONE IN PREVENTION OF ACETAMINOPHEN-INDUCED HEPATOTOXICITY ENHANCED BY FISH OIL IN MALE WISTAR RATS

It has been reported that fish oil protects the rat liver against acetaminophen (APAP) induced toxicity; however, this finding is controversial. The present study was undertaken to investigate the effects of fish oil-enriched diet on APAP-induced liver injury in Wistar rats. Rats were fed a diet supplemented with either 8% fish oil or 8% corn oil, or standard rat feed for 6 wk. After an overnight fast, rats in each group were given either 2 g/kg APAP or saline orally. Our findings showed that APAP increased serum alanine aminotransferase (ALT) and that this rise was potentiated in the presence of dietary fat. Further fish oil ingestion increased the glutathione (GSH) content in rat liver; however, this was not effective in protecting liver from APAP-induced toxicity. Data suggest that GSH may be necessary to detoxify APAP metabolites, which are known to induce hepatotoxicity but are increased by dietary fat.     

BIOCHEMICAL STUDIES OF VERRUCARIN J IN MALE MICE LIVER

Eight treated groups of 10 male mice that were injected with two sublethal doses of verrucarin J (0.9 and 0.5 mg/kg body weight) for two, four, six and eight weeks (for each dose) were compared with eight groups of control mice. Serum total protein and albumin were decreased in treated groups. Globulins, total lipids, total bilirubin, conjugated bilirubin and unconjugated bilirubin were increased compared with the control groups. Liver disease is often clinically assessed using serum enzyme activities such as glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, γ-glutamyl transferase, alkaline phosphatase, and 5′-nucleotidase. The levels of these enzymes were increased in serum of treated groups compared with the control groups. The results indicate that the second dose produced less dramatic biochemical changes than the first dose in the above-mentioned parameters.     

杏丁注射液细菌内毒素检测

目的:建立杏丁注射液细菌内毒素的检查方法。方法:按中国药典2000版二部附录ⅪE、ⅪⅩ F进行实验和结果判断。结果:用标示灵敏度为0.5EU·ml~(-1)的鲎试剂,杏丁注射液在≤最大有效稀释倍数(6—MVD)时,对细菌内毒素检查无干扰作用。13批杏丁注射液中细菌内毒素量均小于3EU·ml~(-1)。结论:可以用细菌内毒素检查法(凝胶法)代替家兔热原检查法控制其热原。     

mTOR信号通路在大鼠可卡因自身给药复燃中的作用

背景:哺乳动物雷帕霉素靶蛋白(mammalian target of rapamycin,mTOR)是一种丝氨酸/苏氨酸激酶,其作用可被雷帕霉素所阻断。mTOR活化后参与调节基因转录、蛋白质翻译起始、核糖体生物合成、细胞凋亡等多个生物学过程。mTOR信号转导通路在学习记忆等神经活动的长期可塑性过程起着重要的作用。药物成瘾的过程是药物作用于中脑多巴胺奖赏系统发挥奖赏效应并使之发生长期神经可塑性改变的过程。长期使用成瘾性药物能产生强烈的心理渴求,使得药物成瘾者在戒断后再次暴露于药物、相关环境或压力时极易发生复吸。目前关于mTOR在药物成瘾中的作用研究较少,已有研究证实mTOR信号转导通路参与了药物作用于中脑边缘多巴胺系统引起的奖赏效应和长期神经可塑性,但mTOR信号通路在药物成瘾后发生复吸中的作用尚不清楚。目的:本研究旨在通过大鼠可卡因自身给药戒断后的复燃模型探讨mTOR信号通路在药物成瘾戒断后发生复吸行为中的作用,从而为成瘾神经生物学机制的研究和临床戒毒治疗提供新的实验依据。方法:(1)建立大鼠可卡因自身给药模型(0.75mg·kg-1 infusion,3h·d-1),经过消退后给予药物相关线索暴露诱导复燃行为,比较经过暴露和未经过暴露大鼠伏隔核中mTOR下游靶蛋白p70s6k磷酸化水平变化;(2)建立大鼠可卡因自我给药模型,经过消退后给予药物相关线索暴露诱导复燃行为。暴露前30min在大鼠伏隔核core/shell部分别微注射mTOR抑制剂雷帕霉素或溶媒,观察其对大鼠的复燃行为的影响,并检测暴露后大鼠伏隔核不同脑区中p70s6k磷酸化水平变化;(3)建立大鼠可卡因自身给药模型,经过消退后给予10mg可卡因点燃诱导复燃行为。可卡因点燃30min前在大鼠伏隔核core/shell部分别微注射雷帕霉素或溶媒,观察其对大鼠的复燃行为的影响;(4)建立大鼠可卡因自身给药模型,当大鼠获得稳定的自身给药行为后,在大鼠伏隔核core/shell部分别微注射雷帕霉素或溶媒,d2继续进行可卡因自身给药训练,观察雷帕霉素对可卡因强化效应的影响。结果:药物线索暴露后伏隔核core部的磷酸化p70s6k水平与未暴露组相比明显上升,说明药物线索暴露诱导的复燃能激活伏隔核的mTOR信号通路。在大鼠伏隔核core部给予雷帕霉素微注射能够抑制药物相关线索诱导的复燃行为,而伏隔核shell部给药无效。大鼠伏隔核core部注射雷帕霉素导致伏隔核core部磷酸化p70s6k水平下降,shell部磷酸化p70s6k水平不变。两个脑区的总p70s6k表达水平均无变化。在大鼠伏隔核shell部给予mTOR抑制剂雷帕霉素微注射能够抑制可卡因点燃诱导的复燃行为,而伏隔核core部给药无效。说明抑制伏隔核mTOR信号通路能够抑制药物相关线索或可卡因诱导的复燃行为,且此作用具有脑区特异性。行为学结果还表明,大鼠获得稳定的可卡因自身给药行为后,在大鼠伏隔核core/shell部微注射雷帕霉素均不能够改变已获得的自身给药行为。说明抑制伏隔核mTOR信号通路不影响可卡因的强化效应,雷帕霉素对大鼠戒断后复燃行为的抑制效应并不是由于其降低了可卡因的强化效应。结论:本研究通过一系列实验证实了在伏隔核shell和core部分别给予雷帕霉素能有效抑制大鼠自身给药戒断后由药物点燃和药物相关线索诱导的复燃行为,这一效应是通过抑制伏隔核的mTOR信号通路实现的。mTOR信号通路脑区特异性的参与了自身给药戒断后的复燃行为。本研究结果为成瘾的神经生物学机制研究和临床开发防复吸药物提供了新的依据。     

双环醇对扑热息痛引起小鼠肝脏能量代谢和线粒体功能障碍的影响

目的　研究双环醇对扑热息痛(对乙酰氨基酚)引起小鼠肝能量代谢紊乱和线粒体功能障碍的保护作用。方法　小鼠ip扑热息痛120mg·kg^-1 引起急性肝损伤,观察血清谷丙转氨酶(ALT)和谷草转氨酶(AST)水平、肝活体磷谱、肝线粒体膜流动性及线粒体ATPase活性的改变。结果　双环醇可显著抑制扑热息痛中毒小鼠PME/ATP及PME/PDE的升高。双环醇(200mg·kg^-1)可显著降低扑热息痛导致的线粒体膜流动性下降,并对线粒体ATPase活性降低有显著保护作用。结论　双环醇可保护扑热息痛导致的急性肝损伤,使肝脏能量代谢和磷脂代谢趋于正常,并对损伤的线粒体功能有显著的保护作用     

联苯双酯对他克林引起的肝损伤的保护作用

目的　观察联苯双酯(DDB)对他克林(THA)诱发小鼠肝损伤的保护作用。方法　小鼠一次poTHA(56mg·kg^-1) ,观察12h内动物血清ALT ,肝脏MDA和动物体温的改变;分光光度法测定小鼠脑乙酰胆碱酯酶活性;酶动力法测定小鼠肝微粒体7-乙氧基香豆素脱乙基酶和UDP葡糖醛酸转移酶(UDPGT)的活性;荧光法测定线粒体膜电位的改变。结果　DDB 200 mg·kg^-1 可明显保护THA引起的小鼠体温下降、血清ALT和肝脏MDA的升高。DDB(100 μmol·L^-1 )可减轻THA造成的大鼠线粒体膜电位降低。DDB还可提高小鼠肝微粒体7-乙氧基香豆素脱乙基酶的活性,但对UDPGT无影响。结论　DDB似通过降低肝脏脂质过氧化反应、提高线粒体膜稳定性、调节THA代谢酶活性发挥其肝保护作用     

二甲胺四环素增强博安霉素的抗肿瘤转移作用

博安霉素对小鼠Lewis肺癌的肺转移有显著抑制作用;用等毒性剂量进行比较,博安霉素的肺转移抑制率高于丝裂霉素。单独给博安霉素(5mg·kg^-1)对肺转移抑制率为67%,对其中大转移瘤结(直径>2mm)的抑制率为85%;博安霉素与二甲胺四环素(5mg·kg^-1)联合使用时,对肺转移瘤以及时大转移瘤结的抑制率分别为88%和100%,两药相互作用指数CDI<0.5(P<0.01),表明二甲胺四环素能明显增强博安霉素的抗转移作用。酶联免疫测定证明,二甲胺四环素能降低肺巨细胞癌PG细胞IV型胶原酶的表达,Fura-2/AM荧光法测定,二甲胺四环素能显著降低PG细胞内游离Ca²⁺的水平。本研究结果提示博安霉素与二甲胺四环索联合用药可能有利于控制肿瘤转移,二甲胺四环素的增效机制可能与抑制IV型胶原酶的表达、干扰肿瘤侵袭与转移的过程有关。     

THE EFFECTS OF COCAINE AND LIGNOCAINE ON THE RAT RIGHT VENTRICLE IN VITRO

• 1 The effects of cocaine and lignocaine on the contractile responses to field stimulation and to exogenously applied agents, in the absence of other stimuli, have been investigated in the rat right ventricle using methods we have recently described (Doggrell & Vincent, 1981a). In addition the effects of ³H accumulation from (?)-[³H]-noradrenaline and on the spontaneous and field stimulation-induced overflow of ³H, following preloading of the tissue with (?)-[³H]-noradrenaline, are reported.
• 2 Cocaine, but not lignocaine, inhibited the accumulation of ³H from (?)-[³H]-noradrenaline. The spontaneous overflow of ³H, following preloading of the tissue with (?)-[³H]-noradrenaline was not altered by cocaine, 10μ, or lignocaine, 100μM. 10μM Lignocaine had no effect on the overflow of ³H evoked by field stimulation at 5Hz. Lignocaine, 100μM, increased and cocaine, 1 and 10μM, reduced the decline in evoked release of ³H. This effect of lignocaine probably represents a decrease in nerve excitability and that of cocaine inhibition of neuronal uptake of noradrenaline.
• 3 Cocaine, μM, reduced the rate of beat response to tyramine, 1μM, alone, probably by inhibiting the neuronal uptake process.
• 4 Cocaine, 1 and 10μM, had no effect on the contractile responses to field stimulation (at 2 and/or 5Hz). The rate of beat to (?)-noradrenaline or (?)-isoprenaline, 1μM, alone was decreased by cocaine, 10μM. Lignocaine, 10μM, reduced the force of contractions to field stimulation at 5 Hz and the responses to (?)-noradrenaline or (?)-isoprenaline alone. It is suggested that the inhibitory effects of cocaine and lignocaine on responses to (?)-isoprenaline in the rat right ventricle are due to a decreased postjunctional membrane excitability. The inability of 10μM cocaine to potentiate contractile responses to endogenous or exogenous (?)-noradrenaline as a consequence of the inhibition of neuronal uptake is also probably due in part to decreased post-junctional excitability of the right ventricle.

     

鱼腥草注射液中细菌内毒素定量检测研究

目的：对鱼腥草注射液进行添加细菌内毒素干扰回收试验，建立定量检测鱼腥草注射液中污染内毒素试验方法。方法：采用中国药典2000年版附录检测细菌内毒素的动态浊度法，结果：鱼腥草注射液在稀释至12倍时已无干扰因素影响，内毒素回收率均在50％－200％范围内，结论：使用细菌内毒素动态浊度法定量检测鱼腥草注射液的污染内毒素是可行的，可用细菌内毒素定量检查法代替家兔热原检查法。     

异丙酚对可卡因抑制PC12神经细胞增殖的保护作用

目的·· :研究异丙酚对可卡因抑制PC12神经细胞增殖的细胞毒性的影响。方法··:应用噻唑蓝(MTT)比色法测定不同浓度可卡因对PC12细胞增殖的毒性作用 ,以及异丙酚对可卡因所致细胞增殖毒性的影响 ,并观察细胞形态学改变。结果·· :可卡因作用于PC12细胞72h后 ,细胞光密度(OD)值呈剂量依赖性下降 ;单独应用可卡因160μmol·L-1 组和320μmol·L-1 组OD值明显降低 (P<0.01) ,而同时给予异丙酚50μmol·L-1 后 ,可卡因160μmo·L -1组PC12细胞OD值明显增加 (P<0.01) ,但可卡因320μmol·L -1组同时给予异丙酚后未见OD值显著改善 (P>0.05)。结论··:异丙酚对可卡因抑制PC12细胞增殖有一定的保护作用     

1,3-二苯-1,3-丙二酮对可卡因致小鼠肝毒性及神经毒性的保护作用

目的:探讨1,3-二苯-1,3-丙二酮(DPPD)对可卡因致小鼠急性肝损伤及神经毒性的保护作用。方法:可卡因急性肝损伤模型采用♂C57BL/6N小鼠,DPPD(200,400,800 mg·kg–1/d,ig)预给药4 d,末次给药30 min后,sc可卡因70 mg·kg-1造模,24 h后处死,测定血清ALT,AST,LDH的活性及肝脏MDA含量,观察肝脏病理变化。DPPD抗可卡因神经毒性实验采用♂ICR小鼠,DPPD预给药3 d(给药剂量同前),末次给药30 min后,sc可卡因20mg·kg-1造模,记录小鼠0-180 min的活动次数。结果:可卡因70 mg·kg-1致部分小鼠死亡(5/7),存活小鼠血清ALT,AST,LDH活性及肝脏MDA含量显著升高,肝脏病理损伤明显,而DPPD预给药组无死亡,血清ALT,AST,LDH活性及肝脏MDA含量显著降低,肝脏损伤明显改善,呈剂量-效应关系;DPPD抗可卡因神经毒性研究发现,DPPD预给药组小鼠自主活动量较模型组显著降低。结论:DPPD对可卡因致小鼠急性肝毒性及神经毒性有拮抗作用。