L-精氨酸对梗阻性黄疸大鼠肾的保护作用

目的 :探套 L -精氨酸对于梗阻性黄疸大鼠肾的影响及相应的机制。　方法 :采用双重结扎大鼠胆总管造成梗阻性黄疸模型 ,14天后 ,不同组大鼠分别给予 L-精氨酸 (L- Arg) [5 0 0 mg/ (kg· d) ]或 L-精氨酸甲酯 (L- NAME)[10 mg/ (kg· d) ],2 1天后 ,测定肾组织匀浆中一氧化氮 (NO)、超氧化物歧化酶 (SOD)、丙二醛 (MDA)的含量以及肾功能改变 ,采用 Western杂交技术比较不同组大鼠肾热休克蛋白 70 (HSP70 )的表达情况 ,并观察肾形态学改变。　结果 :胆道梗阻后 2 1天 ,肾组织中 NO及 MDA含量均增高 ,而 SOD水平下降 ,肾功能受损 ,给予 L - Arg组大鼠肾组织中 NO含量较单纯梗阻性黄疸组增加显著 (P<0 .0 1) ,而 SOD活性增高 (P<0 .0 1) ,MDA水平降低 (P<0 .0 5 ) ,肾功能改善 ,而且 HSP70表达明显增强。肾组织结构损伤减轻。相反 ,给予 L- NAME组大鼠肾组织 NO含量与单纯梗阻性黄疸组相比 ,明显降低 (P<0 .0 5 ) ;SOD活性无明显增高 ,MDA水平亦无明显降低 ,肾功能未见改善 ,反而有损害加重趋势 ,HSP70表达无明显增加 ,肾组织损伤未见减轻。　结论 :L - Arg对梗阻性黄疸大鼠肾可起保护作用 ,这可能是通过 L- Arg增加 NO的通路实现的。     

L-精氨酸干预治疗对COPD大鼠肺动脉压的影响

[目的]探讨L-精氨酸干预治疗对慢性阻塞性肺疾病(COPD)大鼠模型肺动脉压力的影响。[方法]应用气道内注入脂多醣和香烟熏吸法建立COPD大鼠模型,测定各组大鼠肺动脉平均压力(mPAP)、肺组织匀浆的一氧化氮(NO)含量和诱导型一氧化氮合酶(iNOS)及内皮型一氧化氮合酶(eNOS)的表达情况。[结果]应用L-精氨酸干预后,大鼠肺动脉压降低,肺组织的iNOS表达减弱,而NO含量升高,eNOS表达增强。[结论]L-精氨酸干预治疗可降低COPD大鼠的肺动脉压,对COPD的发展有延缓作用。     

热休克蛋白70对急性坏死性胰腺炎大鼠肺损伤保护作用的实验研究

目的探讨热休克蛋白70(Hsp70)对急性坏死性胰腺炎(ANP)大鼠肺损伤的保护作用。方法温生理盐水(42~43℃)持续灌洗大鼠腹腔30 m in诱导胰腺组织高表达Hsp70,10 h后诱导大鼠急性胰腺炎(AP),术后6、12 h检测血清和肺组织TNF-α水平,肺湿重系数,肺泡灌洗液中蛋白含量和细胞数,肺组织常规病理评分及Hsp70免疫组化病理改变。结果与ANP组相比,42℃生理盐水腹腔持续灌洗预处理能明显降低SNP术后6 h和12 h的血清和肺组织TNF-α水平(P<0.05),并降低肺湿重系数、肺泡灌洗液中蛋白含量和细胞数水平以及肺组织常规病理评分(P<0.05)。结论Hsp70对SNP肺损伤有明显的保护作用,其机制可能是下调肺组织内TNF-α的表达。     

L-精氨酸对热应激大鼠血清皮质醇变化的影响

目的 观察补充L-精氨酸对热应激大鼠血清皮质醇含量的变化，探讨L-精氨酸对热应激胸腺具有保护作用的可能机制。方法 青春期雄性SD大鼠，随机分为对照组、L-精氨酸灌胃组、维生素E饲料组，观察各组常温和41℃应激1，2h后及热应激后0，4，8h3个时间点的血清皮质醇的变化。结果 (1)高温应激后各组血清皮质醇含量均明显升高，其中热应激后4h升到最高，补充L-精氨酸组明显低于未补充组；(2)补充适量L-精氨酸可减轻热应激大鼠胸腺和脾脏的急性萎缩。结论 适量的L-精氨酸能够抑制热应激引起的血清皮质醇含量的显著升高及减小胸腺和脾脏指数，适量的L-精氨酸对热应激大鼠胸腺具有明显的保护作用，可以增强机体的免疫力。     

非酒精性脂肪性肝病大鼠肝组织NO和iNOS的变化

目的观察非酒精性脂肪性肝病大鼠肝组织NO和iNOS的变化,研究NO和iNOS在非酒精性脂肪性肝病中的作用机制。方法雄性SD大鼠20只,按体重随机分层分2组:正常对照组饲喂基础饲料,模型组以高脂饲料,喂养16W后处死大鼠,测体重、肝脏湿重,检测血清ALT、AST、ALP、胆碱酯酶(CHE)、总胆汁酸,病理组织学观察,采用硝酸还原法检测肝组织NO水平和以H3-精氨酸转化实验测定肝组织iNOS活性。结果16W末,模型组肝脏出现明显肝细胞脂肪变性和肝小叶炎症,肝指数、ALT、AST、ALP、胆碱酯酶(CHE)、总胆汁酸均高于对照组(P<0.05),模型组肝组织NO水平较正常组显著增高,模型组大鼠肝组织中iNOS活性也较正常组有明显提高,(P均<0.05)。结论高脂喂养脂肪肝大鼠肝脏中iNOS活性增强,以及诱导生成的NO水平也增高,iNOS,NO在脂肪肝肝损害中发挥重要作用。     

缺氧预处理预防大鼠手术后疲劳综合征的研究

[目的]探讨缺氧预处理对大鼠手术后疲劳综合征模型的作用并对其作用机制进行初步的探讨.[方法]建立大鼠手术后疲劳综合征模型,观察缺氧预处理对大鼠体力活动及血清超氧化物歧化酶和丙二醛水平的影响.[结果]缺氧预处理能改善模型术后大鼠的活动能力.同时,缺氧预处理组大鼠血清超氧化物歧化酶水平明显升高,丙二醛水平明显降低.[结论]缺氧预处理可提高大鼠的抗氧化能力,对手术后疲劳综合征有明显的改善作用.     

硝酸酯类药物对预防缺氧性肺动脉高压的研究

缺氧性肺动脉高压 (HPH)是慢性肺心病的重要发病环节 ,其主要特点是肺血管收缩反应增强和肺血管结构重建。本研究通过观察大鼠急性缺氧时及硝酸甘油治疗后平均肺动脉压 (mPAP)、血中内皮素 -1(ET -1)和一氧化氮 (NO)水平的变化 ,进一步探讨缺氧性肺动脉高压的发生机制及硝酸酯类药物降低肺动脉压的作用机理。1　材料和方法1 1　实验动物 :成年雄性大鼠 3 0只 ,平均体重 3 50g ,随机平均分为 3组 :常氧对照组 :吸入 (2 1 0± 1 5) %氮氧混合气 ;急性缺氧组 :吸入 (9 0± 1 5) %氮氧混合气 ;治疗组 :缺氧过程中 ,同时以硝酸甘油 4μg/min…     

吡格列酮减轻急性出血坏死性胰腺炎肺损伤的机制研究

目的 探讨吡格列酮减轻急性出血坏死性急性胰腺炎肺损伤作用的机制.方法 采用逆行胰胆管牛磺胆酸钠注射制造急性出血坏死性急性胰腺炎大鼠模型,分假手术组、急性出血坏死性急性胰腺炎组、吡格列酮治疗组.硝酸还原酶法检测肺组织NO的浓度变化,RT-PCR和Western Blot检测肺组织TLR2,4 mRNA表达变化.结果 与假手术组比较,急性出血坏死性急性胰腺炎组肺组织TLR2,4表达明显增高,NO浓度降低,肺损伤加重（P〈0.05）.吡格列酮治疗组TLR2,4表达降低,肺组织NO升高,肺损伤减轻（P〈0.05）.结论 吡格列酮可能通过抑制TLR2,4 mRNA的表达,提高NO的合成和释放,减少细胞因子的合成及释放,减轻AHNP并发肺损伤.     

铀矿尘对大鼠肺组织及血浆中转化生长因子-β1和一氧化氮水平影响

目的探讨铀矿尘致大鼠肺纤维化过程中,肺组织和血浆中转化生长因子-β1(TGF-β1)、一氧化氮(NO)水平变化。方法 60只成年Wistar大鼠,随机分为铀矿尘组与对照组。采用一次性非暴露式气管灌注法,铀矿尘组一次性气管内灌注质量浓度为20 g/L铀矿粉尘悬液1 ml,对照组一次性气管内灌注生理氯化钠溶液1 ml。每组分别于染尘后第7、14、21、30及60天随机处死6只动物,取周围血及肺组织。肺组织形态学观察采用HE染色法;肺组织及血浆中TGF-β1水平的测定采用酶联免疫吸附法(ELISA法);肺组织及血浆中NO水平的测定采用硝酸还原酶法。结果实验观察期内铀矿尘致大鼠肺组织纤维增生病变;铀矿尘在致肺组织纤维化过程中,可引起肺组织及血浆中TGF-β1及NO水平增高,且在染尘后第30、60天时其肺组织和血浆中TGF-β1及NO水平与对照组比较,差异有统计学意义(P<0.05);肺组织与血浆中TGF-β1及NO水平变化存在直线正相关(rTGF=0.887,P<0.05;rNO=0.958,P<0.05)。结论在铀矿尘致大鼠肺纤维化过程中,其肺组织和血浆中TGF-β1和NO的水平可见明显增高,肺组织与血浆中TGF-β1及NO水平变化存在直线正相关。     

褪黑素对脓毒症大鼠心肌损伤的保护作用研究

目的:探讨褪黑素对脓毒症心肌损伤的作用及其机制。方法:30只SPF级雄性SD大鼠随机分为正常对照组、脓毒症组、褪黑素预处理组。采用盲肠结扎穿刺法制作脓毒症大鼠模型,褪黑素预处理组术前7d每日腹腔注射褪黑素4mg/kg。盲肠结扎穿刺术后12h经右颈总动脉左心室内插管监测各组大鼠LVSP、LVEDP、±dp/dt max等血流动力学指标,收集大鼠血清检测肌酸激酶同工酶CK-MB、乳酸脱氢酶LDH的含量,测定大鼠心肌组织MDA、SOD和 NO含量。结果:脓毒症组大鼠LVSP、±dp/dt max均有所降低,LVEDP升高,而褪黑素预处理组以上各项指标均有不同程度改善;脓毒症模型组大鼠血清CK-MB、LDH以及心肌组织MDA、NO含量均明显升高,心肌组织SOD含量明显减少(P0.05);褪黑素预处理明显降低了大鼠血清CK-MB、LDH以及心肌组织MDA、NO含量,增加了大鼠心肌组织SOD的活力。结论:褪黑素预处理通过抑制氧化损伤,减轻脓毒症心肌损伤。     

被动吸烟致大鼠肺损伤及其对细胞因子的影响

目的 观察长期被动吸烟所致大鼠肺损伤情况及春对体内一氧化氮、白细胞介素－６、８（ＩＬ－６、ＩＬ－８）影响作用如何。方法 采用生化分光光度法测定ＮＯ＾－２／ＮＯ＾－３含量,代表大鼠体内ＮＯ水平。用酶联免疫标记法测定ＩＬ－６、ＩＬ－８含量。结果单纯吸烟组,血清、支气管肺泡灌洗液、肺组织中的ＮＯ含量均明显低于正常对照组。ＩＬ－６、ＩＬ－８含量均高于正常对照组。结论 长期被动吸烟可引成肺组织一定程度的损伤     

iNOS基因甲基化对交通相关PM_(2.5)诱导大鼠哮喘加重中NO的调控作用

目的探讨交通相关PM_(2.5)能否改变iNOS基因DNA启动子区甲基化水平从而调控大鼠哮喘加重中NO的释放水平。方法选择45只雄性SD大鼠,用卵清蛋白致敏、激发建立大鼠哮喘模型,在激发阶段以气管滴注染毒不同剂量(1.5、6、24 mg/kg)PM_(2.5),构建PM_(2.5)刺激的哮喘加重模型。实验大鼠随机分为5组,分别为生理盐水对照组、哮喘组及PM_(2.5)低、中、高剂量刺激哮喘组。收集支气管肺泡灌洗液(BALF),计数细胞总数和嗜酸性粒细胞所占百分比;制作肺组织病理切片,以HE染色观察病理变化;以甲基化阳性对照标准曲线方法测定iNOS基因DNA启动子区甲基化水平,以qRTPCR测定iNOS mRNA水平,以硝酸还原酶法测定BALF中NO含量。结果哮喘组及PM_(2.5)低、中、高剂量刺激哮喘组大鼠的左肺脏器系数、BALF中嗜酸性粒细胞百分比、肺组织iNOS mRNA水平、BALF中NO含量均高于生理盐水对照组,肺组织iNOS基因DNA启动子区甲基化水平低于生理盐水对照组,差异均有统计学意义(P0.05);PM_(2.5)低、中、高剂量刺激哮喘组大鼠的BALF中嗜酸性粒细胞百分比、NO含量均高于哮喘组,肺组织iNOS基因DNA启动子区甲基化水平和BALF中细胞总数低于哮喘组,差异均有统计学意义(P0.05)。大鼠肺组织iNOS基因DNA启动子甲基化水平与iNOS mRNA水平呈负相关(r=-0.556,P=0.003),BALF中NO含量与iNOS mRNA水平呈正相关(r=0.446,P=0.025)。结论交通相关PM_(2.5)可降低iNOS基因DNA启动子区甲基化水平,后者可能参与调控大鼠哮喘加重中NO释放水平。     

Dietary protein or arginine deficiency impairs constitutive and inducible nitric oxide synthesis by young rats.

Effects of dietary protein or arginine deficiency on constitutive and lipopolysaccharide (LPS)-induced nitric oxide (NO) synthesis were determined in young rats by quantifying urinary nitrate excretion. In Experiment 1, 30-d-old rats (n = 16) were divided randomly into two groups (n = 8/group) and pair-fed on the basis of body weight semipurified isocaloric diets containing 20 or 5% casein. In Experiment 2, 30-d-old rats (n = 24) were divided randomly into three groups (n = 8) and pair-fed on the basis of body weight purified isonitrogenous and isocaloric diets (composed of amino acids) containing 0.0, 0.3 or 1.0% L-arginine. In both experiments, daily collection of urine was initiated 10 d after the start of pair-feeding. On d 17 after the pair-feeding was initiated, LPS (1 mg/kg body wt) was injected intraperitoneally into rats, and urine was collected daily for an additional 7 d. In Experiments 3 and 4, activities of constitutive and inducible NO synthases were measured in macrophages and various tissues from protein- or arginine-deficient rats (n = 6). Body weight was lower in rats fed the 5% casein diet or the 0.0 and 0.3% arginine diets than in those fed 20% casein or 1% arginine, respectively. Dietary protein or arginine deficiency decreased serum concentrations of arginine and urinary nitrate excretion before and after LPS treatment, indicating impaired constitutive and inducible NO synthesis. Protein malnutrition reduced constitutive and inducible NO synthase activities in brain, heart, jejunum, lung, skeletal muscle and spleen, and inducible NO synthase activity in macrophages. Because NO is a mediator of the immune response and is the endothelium-dependent relaxing factor, impaired NO synthesis may help explain immunodeficiency and cardiovascular dysfunction in protein- or arginine-deficient subjects.     

SD大鼠生长发育指标和主要脏器正常参考值的探讨

目的：为掌握清洁级SD大鼠体重等生长发育指标和主要脏器正常参考值并进行探讨。方法：SD离乳大鼠,120只（雌雄各半）,正常喂养4～8周,测定并计算各项指标。结果：每周摄食量与体重呈线性正相关,食物利用率与体重呈线性负相关;雄性大鼠总增重和总食物利用率明显高于雌性大鼠（P〈0.01）;雄性大鼠肝、肾、脾重量显著高于雌性大鼠,其差异均有统计学意义（P〈0.01）,但雌雄大鼠脏体比之间的性别差异无统计学意义（P〉0.05）。结论：不同的实验动物环境对大鼠的正常值有一定的影响,本项实验的SD大鼠正常参考值结果对毒理学研究具有一定的实际应用价值。     

NO2-/NO3- levels in blood and principal organs in rats treated with lipopolysaccharide

It is well revealed that activation of macrophages stimulated by endotoxin resulted in induction of nitric oxide synthase which catalyze nitric oxide (NO) formation from L-arginine. Consequently, blood concentrations of NO2-/NO3- (NOx-) are shown to increase. We studied on pharmaco/toxicokinetics of NOx- in serum and principal organs in Wistar male rats after i.p. administrations of LPS and NaNO3. The serum levels of NOx- at 1 h and 6 h after nitrate administration (10 mg/kg, i.p.) were 240 and 120 microM, respectively. Tissue levels of NOx- in lung, liver and kidneys were ca.1/2 of the serum level. Those levels in spleen and brain were ca.1/4 and 1/10 of the serum level, respectively. The correlation of NOx- levels in serum and these 5 organ tissues between 1 h and 6 h after administration of nitrate was r = 0.992 suggesting no specific accumulation of NOx- in these organs. The serum level of NOx- at 18 h after LPS treatment (1 mg/kg, i.p.) was 430 microM. The correlation of NOx- levels in serum and 5 organ tissues between LPS and nitrate administrations was shown to be r = 0.851. NOx- levels of serum, lung, kidneys and brain showed good correlation but liver and spleen showed out of the correlation. The liver tissue level of NOx- after LPS treatment was low compared with the expected value from the serum level. The reason may be explained partially by the liver weight increase and the liver toxicity with increased GPT and gamma-GT levels due to LPS. Contrary to this, NOx- level of spleen tissue after LPS treatment was more than 2-fold compared with the expected value from the serum level suggesting NO formation in the spleen. This was supported by the markedly high concentration (73.2 nmol/g tissue) of NO2- in the spleen tissue. NO2- levels in lung (34.5 nmol/g tissue) and brain (14.3) were also found to be significantly high after stimulation with LPS suggesting NO formation in these organs. Increased formation of NO2- in these organs by LPS stimulation suggests the formation of active nitrogen oxides such as N2O3 which is an effective nitrosating agent in non-acidic conditions in vivo.     

Dietary L-arginine supplementation enhances endothelial nitric oxide synthesis in streptozotocin-induced diabetic rats

This study tested the hypothesis that dietary arginine supplementation increases endothelial tetrahydrobiopterin (BH(4)) availability for nitric oxide (NO) synthesis in diabetic rats. Streptozotocin-induced diabetic rats either were given unrestricted access to a casein-based diet (Expt. 1) or were pair-fed the diet on the basis of the food intake per kg of body weight of nondiabetic rats (Expt. 2). Beginning 1 d after vehicle or streptozotocin injection, arginine-HCl (1.51%) or alanine (isonitrogenous control, 2.55%) was added daily to the drinking water for nondiabetic rats, whereas concentrations were adjusted (0.43% arginine-HCl and 0.73% alanine) in the drinking water for diabetic rats (which consumed more water) to ensure isonitrogenous provision. At 2 wk after the initiation of arginine supplementation, coronary endothelial cells and plasma were obtained for the measurement of NO synthesis and metabolites. In both experiments, plasma and endothelial concentrations of N(G)-monomethylarginine, asymmetric dimethylarginine, and symmetric dimethylarginine increased, but those of arginine as well as endothelial BH(4) availability and NO synthesis decreased in diabetic rats, compared with nondiabetic rats. In both diabetic and nondiabetic rats, arginine supplementation increased plasma concentrations of arginine and insulin, endothelial concentrations of arginine and BH(4), and endothelial NO synthesis, but did not affect plasma and endothelial concentrations of methylarginines or plasma concentrations of homocysteine. Dietary arginine supplementation or provision of a BH(4) precursor normalized endothelial NO synthesis in diabetic rats. Arginine supplementation did not affect plasma glucose levels in nondiabetic rats, but reduced body weight loss and plasma glucose levels in diabetic rats. Thus, dietary L-arginine supplementation stimulates endothelial NO synthesis by increasing BH(4) provision, which is beneficial for vascular function and glucose homeostasis in diabetic subjects.     

游泳运动对慢性支气管炎大鼠肺组织MDA和SOD的影响

目的：探讨有氧运动对慢性支气管炎大鼠肺组织MDA含量和SOD活性的影响。方法：将SD大鼠30只按照随机数字表法分为正常组、模型组和运动模型组,每组10只。采用改良烟熏法建立慢性支气管炎大鼠模型,并对慢性支气管炎模型大鼠进行8周游泳运动干预,检测运动干预后各组大鼠肺组织MDA和SOD含量变化。结果：与正常组相比,慢性支气管炎模型组大鼠体重显著降低（P〈0.05）,运动模型组体重降低不明显。慢性支气管炎模型组大鼠肺组织和支气管肺泡灌洗液（BALF）中MDA含量明显高于正常对照组和运动模型组（P〈0.05）。同时慢性支气管炎模型组大鼠肺组织和支气管肺泡灌洗液（BALF）中SOD含量显著低于正常对照组和运动模型组（P〈0.05）。结论：8周游泳运动明显提高了慢性支气管炎大鼠肺组织SOD活性,降低了MDA含量,提高了大鼠抗氧化损伤能力,减轻了炎症反应,改善了肺功能。     

两种染尘方法对大鼠肺组织病理及细胞因子的影响

目的探讨不同染尘方法对大鼠肺脏器组织病理学和肺组织细胞因子变化影响。方法选取SPF级Wistar健康雄性大鼠84只随机分为对照组、动式染尘组和气管灌注组(各28只),各组大鼠在接触矽尘后于3、14、28和60 d时随机选取7只处死。计算各组大鼠的体重和肺脏器系数;采用苏木素-伊红染色法观察肺组织病理变化,采用Masson染色法评估肺脏胶原纤维化,天狼猩红染色偏振光法观察肺组织胶原纤维面积比变化;采用酶联免疫吸附实验检测肺组织匀浆转化生长因子(TGF)-β1和羟脯氨酸(HYP)水平。结果大鼠染尘后,3、14、28和60 d动式染尘组和气管灌注组大鼠肺脏器病理变化明显,且肺泡炎症和肺纤维化评分与对照组大鼠比较差异均有统计学意义(P<0.05);3、14、28和60 d气管灌注组I型和III型胶原纤维面积百分比均高于动式染尘组,差异均有统计学意义(P<0.05);3和14 d时气管灌注组大鼠肺组织匀浆中TGF-β1含量高于动式染尘组,差异均有统计学意义(P<0.05);28 d时气管灌注组HYP含量高于动式染尘组,差异均有统计学意义(P<0.05)。结论动式吸入染尘和一次性气管灌注染尘均可造成大鼠急性肺损伤,肺组织病理均表现出炎症和纤维化,但一次性气管灌注染尘对大鼠肺组织损伤更严重,病理变化更明显。