诱导型一氧化氮合成酶在迟发性血管痉挛中的作用

目的　以大鼠迟发性脑血管痉挛模型为基础研究诱导型一氧化氮合成酶 (iNOS)在迟发性血管痉挛发展中的作用。方法　 3 2只雄性SD大鼠随机分为实验组和对照组 ,实验组枕大池二次注血诱导迟发性脑血管痉挛 ,对照组枕大池注射生理盐水。第 8天行脑血管造影 ,枕大池抽取脑脊液测一氧化氮 (NO)浓度。逆转录 聚合酶链反应 (RT PCR )法和免疫组织化学法测定并评价iNOSmRNA和蛋白质在基底动脉、大脑中动脉和皮质中的表达。结果　颅内动脉血管减影提示对照组颈内动脉颅内段、大脑中动脉 (MCA)明显变细 ,大脑中动脉中段直径 (MD)与镫骨动脉中段直径 (SD)之比衡量大脑中动脉的管径显示实验组MCA管径较对照组MCA管径减少 3 0 %。对照组脑脊液中NO浓度为 (11.70± 2 .62 ) μmol/L ,实验组脑脊液中NO的浓度为(5 5 .67± 12 .84)μmol/L。iNOSmRNA和蛋白质表达于基底动脉、大脑中动脉和皮质 ,其中基底动脉表达最强。 结论　iNOS作为迟发性脑血管痉挛发展中的关键因素参与血管壁的迟发性损伤。     

Heterogeneity of the effects of combined nitric oxide synthase inhibition on organ perfusion in ovine sepsis

Introduction

Previous studies demonstrated beneficial effects of early neuronal nitric oxide synthase (nNOS) and subsequent inducible NOS (iNOS) inhibition on the development of multiple organ dysfunctions in septic sheep. However, the effects of NOS inhibition on regional blood flow remained undetermined. The current study was conducted to assess the effects of combined NOS inhibition on blood flow to various organs in an ovine sepsis model.

Methods

Eighteen adult, female sheep were randomly allocated to the following groups: (1) sham-injured, non-treated group, (2) injured (smoke inhalation and instillation of Pseudomonas aeruginosa into the lungs), non-treated group (control), and (3) injured, treated group (specific nNOS inhibition from 1 h to 12 h and iNOS inhibition from 12 h to 24 h post-injury). Fluorescent microspheres were injected at baseline and various time points post-injury. At the end of the 24-h experimental period, tissue from various organs was harvested.

Results

Blood flow to the ileum was significantly increased in the control group from 12 h to 24 h versus sham (P < 0.05). This increase was attenuated in the treatment group (P < 0.05). In contrast, blood flow to the pancreas was significantly increased in the treatment group after 12 h and 24 h versus both sham and control (P < 0.05). Blood flow to the spleen was significantly lower after 24 h in the control group versus sham and treatment (P < 0.05 both).

Conclusions

Combined NOS inhibition significantly influenced the pathologically altered organ perfusion during ovine sepsis. However, this treatment strategy showed heterogeneous effects on organ perfusion, perhaps dependent on the sepsis-related degree of NO production and ensuing changes in regional flow.     

血管内皮生长因子对关节软骨细胞诱导型一氧化氮合酶的影响

目的 观察血管内皮生长因子(VEGF)对体外培养的关节软骨细胞诱导型一氧化氮合酶(iNOS)表达的影响。方法 体外培养SD乳鼠关节软骨细胞,用白细胞介素(IL)-1β诱导的方法建立骨关节炎(OA)体外模型,实验分为4组,每组加入不同处理因素进行干预,A组:(正常对照组)不加任何处理因素;B组:10 μg/L VEGF;C组:10 μg/L IL-1β;D组:10 μg/L VEGF+ 10 μg/LIL-1β。采用实时荧光定量PCR( Real Time PCR)检测iNOS mRNA的表达,采用蛋白免疫印迹法( Western blot)检测iNOS蛋白的表达。结果 iNOS mRNA的表达:A组iNOS mRNA无表达,B组(9.64±1.64)、C组(17.27±2.01)及D组(28.93±6.63),3组的iNOS mRNA表达量显著升高,进一步组间比较,D组软骨细胞iNOS的mRNA表达水平明显高于B组(P＜0.01)及C组(P＜0.05),C组软骨细胞iNOS的mRNA表达水平高于B组(P＜0.05)。iNOS蛋白的表达:A组iNOS蛋白无表达,B组(0.44±0.12)、C组(0.74±0.07)及D组(1.38±0.38),3组的iNOS蛋白表达量显著升高,进一步组间比较,D组软骨细胞iNOS的蛋白表达水平明显高于B组(P＜0.01)及C组(P＜0.05),C组软骨细胞iNOS的mRNA表达水平高于B组(P＜0.01)。结论 在OA的发病过程中,VEGF可能通过上调软骨细胞iNOS的表达发挥重要作用。     

白细胞介素-10对大鼠脊髓诱导型一氧化氮合酶基因表达的干预作用

目的　探讨诱导性一氧化氮合酶 (iNOS)mRNA在损伤脊髓组织中的表达规律及白细胞介素 (IL) 10的干预作用。方法　将 64只SD大鼠随机分为 3组 :单纯脊髓损伤 (SCI)组、IL 10组及假损伤组 (Sham组 )。除Sham组不致伤脊髓外 ,均以改良Allen(10 g× 5cm)打击法制作大鼠急性SCI模型 ,IL 10组于脊髓损伤后 3 0min腹腔注射IL 10溶液 10 μg ,分别于伤后 3、12、2 4、48及 72h处死 ,用逆转录 聚合酶链反应 (RT PCR)法测定损伤脊髓组织iNOSmRNA的表达情况 ,并与单纯SCI组和Sham组作对照。结果　脊髓无损伤时未发现iNOSmRNA表达 ,损伤后逐渐出现表达上调 ,于伤后 12h明显增强 ,2 4h达高峰 (0 .60 85± 0 .0 166) ;IL 10组中 2 4h亚组iNOSmRNA表达 (0 .5 70 5± 0 .0 2 0 3 )出现抑制性改变 ,差异有显著性 (P <0 .0 1)。结论　IL 10可明显抑制大鼠脊髓损伤后iNOSmRNA的高表达     

诱生型一氧化氮合酶在胆道感染大鼠肝细胞中的表达

目的　了解诱生型一氧化氮合酶 (induciblenitricoxidesynthase ,iNOS)在胆道感染大鼠肝细胞中表达的情况及其规律。方法　制作大鼠胆道感染模型 ,采用还原型辅酶Ⅱ黄递酶组织化学法检测大鼠肝细胞中iNOS的表达。结果　大鼠胆道感染 2h后肝细胞即有iNOS的表达切片积分光度(13 5 8± 0 6 4) ,与对照组切片积分光度 (3 5 9± 0 2 8)相比 ,P <0 0 1。 8h达到峰值切片积分光度(2 9 2 7± 0 90 ) ,2 4h至 48h仍有较高表达切片积分光度分别为 (19 47± 0 6 5 )和 (19 96± 0 78)。结论　胆道感染时肝细胞可持续高效地表达iNOS ,提示胆道感染时肝脏是合成NO的重要器官 ,并可能对胆道感染的转归具有重要影响     

Coronary flow reserve and nitric oxide synthases after cardiac transplantation in humans

Objective: Coronary endothelial dysfunction may precede morphological changes in both the epicardial conduit and microvascular resistance vessels in heart transplant recipients. Since the development of transplant atherosclerosis is the major limiting factor for long-term survival, the identification of early mediators of vasomotor dysfunction may be of therapeutic interest. We therefore investigated the potential relationship between the expression of nitric oxide synthases (NOS) and coronary endothelial function in human cardiac transplant recipients over time. Methods: Forty-two human cardiac transplant recipients were studied at 1 and 12 months after heart transplantation (HTx). The microvascular coronary flow velocity reserve (CFVR) was tested for endothelium-dependent (acetylcholine) and -independent (adenosine) stimuli by intravascular Doppler flow-wire. Epicardial diameter changes were evaluated by quantitative coronary angiography. Endomyocardial inducible (iNOS) and endothelial constitutive nitric oxide synthase were determined by RT-PCR. Nitric oxide production (nitrite and nitrate (NOx)) and TNF- were measured in plasma samples from the aorta and coronary sinus. Results: CFVR was impaired in 26.1% (n=11) of patients at 1 month and in 31% (n=13) 12 months after HTx. iNOS-mRNA levels were significantly higher in patients with impaired endothelium-dependent CFVR. In addition, only in these patients were TNF- levels higher and these correlated with plasma NOx levels at 1 and 12 months post-HTx (1 month: r=0.81, P=0.001; 12 months: r=0.62, P=0.04). Conclusions: Coronary microcirculatory dysfunction in response to acetylcholine is present in nearly 30% of patients during the first year following transplantation. These patients present with higher iNOS-mRNA expression and TNF- plasma levels. Selective modulation of the TNF-/iNOS-pathway may be of therapeutic value to improve coronary endothelial dysfunction in cardiac transplant recipients.     

重症急性胰腺炎患者血和腹水一氧化氮的动态变化

目的　研究诱生型一氧化氮合酶 (iNOS)活性在重症急性胰腺炎 (SAP)患者中的变化。方法　动态观察 30例重症急性胰腺炎患者发病后血性腹水和外周血一氧化氮 (NO)代谢产物NO2 - /NO3- 的变化。逆转录 聚合酶链反应 (RT PCR)检测外周血单个核细胞iNOSmRNA的变化。结果　SAP患者血性腹水NO2 - /NO3- 含量为 (385 .0± 92 .3) μmol/L与对照组 (41 .3± 1 9.5)μmol/L比较显著升高 (P <0 .0 0 1 )。起病后第 1、7、1 4天外周血NO2 - /NO3- 含量分别为(1 38.8±30 .2 ) μmol/L、(1 2 6 .4± 35 .4) μmol/L和 (77.8± 37.1 ) μmol/L ,随病情好转逐渐下降(P <0 .0 1 )。外周血单个核细胞iNOSmRNA表达在病情严重时显著增强。结论　iNOS活性增强产生过量NO参与重症急性胰腺炎全身病理生理的改变     

诱导型一氧化氮合成酶在大鼠坏死性胰腺炎肺泡巨噬细胞的表达

目的通过研究诱导型一氧化氮合成酶(iNOS)在急性坏死性胰腺炎(ANP)肺泡巨噬细胞(AM)中的表达,明确其在ANP所致肺损伤中的作用。方法72只成年SD大鼠随机分为正常对照组、ANP组、N-硝基-L-精氨酸甲酯(L-NAME)组,每组24只。逆行性胰胆管注射3%牛磺酸钠建立ANP大鼠模型。经支气管肺泡灌洗获取AM,检测支气管肺泡灌洗液(BALF)中蛋白含量、肺组织髓过氧化物酶(MPO)水平,AM分泌iNOS水平及iNOSmRNA表达情况,并行肺组织学检查。结果ANP大鼠AM iNOS的表达随时间进展而增强,同时肺损伤也逐渐加重。L-NAME组则恰好相反,与ANP组相比有显著性差异(P<0.05)。结论ANP发生后,肺泡巨噬细胞iNOS表达增强,并促进肺损伤。     

诱导型一氧化氮合成酶对同系大鼠移植肠运动功能的作用

目的 观察诱导型一氧化氮合成酶(iNOS)对同系原位全小肠移植术后早期移植肠运动功能的影响.方法 分为对照组、移植组、L-NIL治疗组,每组12只大鼠.对照组行十二指肠造瘘术,另两组均行同系原位全小肠移植及十二指肠造瘘术,术后分别给予生理盐水、L-N6-(1-亚氨乙基)-赖氨酸(L-NIL).于术后2 d,各组取6只获取肠段行病理组织学检查,观察炎性损伤程度,并采用RT-PCR和免疫组织化学方法检测iNOS mRNA及蛋白表达水平.各组另6只行小肠传输实验,观测小肠传输功能.结果 移植组呈明显炎性损伤改变,iNOS mRNA及蛋白表达水平(1.278±0.142)%,(56.33±5.16)%较对照组(0.066±0.016)%,(9.17±3.17%)上调(P＜0.01),较对照组小肠传输延迟(P＜0.01).L-NIL治疗组炎性损伤程度较移植组减轻,iNOS mRNA及蛋白表达水平(0.588±0.096)%,(26.17±4.14)%较移植组下调(P＜0.01),且小肠传输延迟有改善(P＜0.01).结论 iNOS在术后早期移植肠炎症损伤及其引发的肠运动功能障碍中可能起重要作用.     

Enteral resveratrol supplementation attenuates intestinal epithelial inducible nitric oxide synthase activity and mucosal damage in experimental necrotizing enterocolitis

Background/Purpose

The release of various enzymes including inducible nitric oxide synthase (iNOS) leads to enterocyte apoptosis through free nitrogen radicals, which in turn leads to impaired mucosal barrier and bacterial translocation with resultant sepsis in necrotizing enterocolitis (NEC). Resveratrol, a polyphenol compound from phytoalexins with antioxidant and scavenger properties, also play a critical role in modulating key enzymes in cell cycle including iNOS. We therefore hypothesized that resveratrol would prevent mucosal damage in experimental NEC in rats.

Methods

Newborn rats were randomized into 3 groups: group 1 was left to breast-feed (BF), whereas group 2 (NEC) was induced by enteral formula feedings twice daily and by being subjected to hypoxia thrice. The third group (R) received the same treatment as the NEC group but the enteral feeds were supplemented with resveratrol. Rats were killed on day 4, and their terminal ileal samples were harvested for histopathologic analysis. Expression of iNOS was assessed by sodium dodecyl sulfate polyacrylamide-gel electrophoresis analysis and immunohistochemistry. Band densities were quantified by using the software NIH image.

Results

The epithelial structure in group BF was normal. In the NEC group, there were marked loss of the brush border, vacuolization, and necrosis. The epithelial structure was found to be preserved in group R. Western blot analysis revealed marked elevation in the expression of iNOS protein at 130 kD molecular weight (band densities in groups BF, NEC, and R were 0.3 ± 3.5, 3.7 ± 2.9, and 0.6 ± 5.1, respectively; P < .01). Immunohistochemical analysis revealed that iNOS staining was significantly increased in the NEC group, whereas it remained minimal for the BF and R groups. Ileal tissue nitrate/nitrite levels for groups BF, NEC, and R were 178.3 ± 7, 191.4 ± 4.1, and 181 ± 3.6 μmol/(L·g), respectively (P < .01).

Conclusions

These findings may provide insights for the beneficial effect of enteral resveratrol supplementation on inflammatory conditions of the bowel including NEC through attenuating the release of iNOS and preservation of mucosal integrity.     

Impact of bronchial circulation on bronchial exudates following combined burn and smoke inhalation injury in sheep

We previously reported bronchial circulation contributes to pulmonary edema and increases shunt fraction following smoke inhalation, and bronchial blood flow significantly increases in inhalation injury. We hypothesized reduction of bronchial blood flow reduces exudation to the airway and ameliorates lung injury from combined burn and smoke insults (B&S injury).

Method

Merino ewes (n = 28) randomly divided into three groups: (1) bronchial artery ligated and injured (injury + ligation group); (2) bronchial artery left intact and injured (injury + no ligation group); (3) bronchial artery ligated but not injured (no injury + ligation group) were subjected to a flame burn and inhalation injury under halothane anesthesia. Parameters were analyzed using Scheffe's post hoc test (P < 0.05). All Groups were resuscitated with Ringer lactate solution and placed on a ventilator for 48 h.

Results

Pulmonary gas exchange (PaO₂/FiO₂) improved in injury + ligation group. Further, obstruction score, an index of airway cast formation, significantly changed between injury + no ligation group compared to both ligation groups.

Conclusion

Bronchial circulation plays a significant role in lung injury after B&S injury, and reduction of bronchial blood flow by bronchial artery ligation reduces bronchial exudates, resulting in improved gas exchange.     

内源性CO和NO在大鼠脑缺血-再灌注损伤中的作用

目的 研究血红素氧合酶-1(heme oxygenase-1,HO-1)/一氧化碳(CO)体系和诱导型一氧化氮合酶(inducible nitric oxide synthase,iNOS)/一氧化氮(NO)体系在大鼠脑缺血-再灌注损伤中的相互作用,探讨脑保护策略.方法 24只Wistar大鼠随机均分为四组:脑缺血-再灌注+锌原踮啉组(Z组)、脑缺血-再灌注+氨基胍组(A组)、脑缺血-再灌注组(IR组)、假手术组(C组).Z组和A组夹闭两侧颈总动脉前30 min腹腔分别注射锌原卟啉45 μmol/kg或氨基胍500 mg/kg,C组和IR组腹腔注射等量生理盐水.缺血20 min再灌注6h后处死大鼠取海马,检测大鼠海马组织中CO、NO、SOD、MDA量的变化及HO-1-mRNA和iNOS-mRNA表达水平;电镜观察海马线粒体的变化.结果 与C组相比,IR组CO、NO、MDA的含量增高,SOD降低,HO-1-mRNA和iNOS-mRNA表达增高(P<0.01),电镜观察线粒体受损.与IR组相比,Z组CO和SOD的量降低,NO、MDA的量增高,HO-1-mRNA的表达降低(P<0.01),电镜观察线粒体受损加重;A组NO、MDA的量降低,SOD的量增高,iNOS-mRNA表达降低(P<0.01),电镜观察线粒体受损减轻.结论 脑缺血-再灌注损伤过程中,iNOS/NO体系介导了神经细胞的损伤,而HO-1/CO体系具有抗损伤的作用;iNOS抑制剂在脑缺血-再灌注损伤过程中对神经细胞有保护作用.     

盐酸戊乙奎醚对创伤性休克兔肠组织诱导型一氧化氮合酶活性和一氧化氮含量的影响

目的 研究盐酸戊乙奎醚(penehyclidine hydrochloride,PHC)对创伤性休克兔复苏后肠黏膜损伤的保护作用.方法 采用Lamson's法建立创伤性休克动物模型,24只健康日本长耳大白兔,采用随机数字表法分为4组(每组6只):对照组(Con组)、生理盐水复苏组(NS组)、PHC处理组(PHC组)、山莨菪碱(anisodamine,ANI)处理组(ANI组).分别在休克前(T1),休克末(T2),复苏后即刻(T3)、2 h (T4)、4 h(T5)、6 h(T6)等6个时间点动态观察MAP和HR,实验结束后放血处死动物取小肠组织,观察肠组织中诱导型一氧化氮合酶(inducible nitric oxide synthase,iNOS)活性和一氧化氮(nitric oxide,NO)含量的变化,光镜下检查组织病理学变化. 结果 各实验组动物T2时的MAP显著降低(均≤45 mmHg)(1 mmHg=0.133 kPa);与Con组和PHC组比较,T3-T6时NS组的MAP显著低于T1时,差异有统计学意义(P＜0.05).与Con组和PHC组比较,T3～T6时NS组的HR较T1时显著降低,差异有统计学意义(P＜0.05);NS组、PHC组和ANI组肠组织iNOS活性[(4.39±0.44)、(1.59±0.49)、(1.62±0.62) U/mg]及NO含量[(5.81±0.27)、(2.10±0.24)、(2.15±0.30) μmol/g]与Con组[(0.70±0.24) U/mg、(0.70±0.32)μmol/g]比较,差异有统计学意义(P＜0.05).NS组肠组织iNOS活性及NO含量显著高于PHC组、ANI组,差异有统计学意义(P＜0.05).病理组织学检查显示PHC组和ANI组肠黏膜损伤较NS组显著减轻. 结论 PHC和ANI有助于稳定创伤性休克兔的血流动力学,对创伤性休克造成的肠黏膜损伤有一定的保护作用,其作用机制可能是通过抑制iNOS活性,从而减少NO含量的生成而起作用的.     

iNOS/NO对结直肠肿瘤发生发展的影响

一氧化氮（nitric oxide,NO）具有广泛的生物学活性。近年来发现一氧化氮（NO）、一氧化氮合成酶（nitric oxide synthase-2,NOS-2）与结直肠肿瘤的发生、发展密切相关,它与环氧化酶（cy-cloxygenase-2,COX-2）之间存在复杂的调控机制。对NO清除剂、NOS抑制剂和释放NO的非甾体抗炎药的研究为结直肠肿瘤的防治提供了一个思路。     

诱导型一氧化氮合酶在异氟醚延迟相预处理心肌保护中的作用

目的研究诱导型一氧化氮合酶(iNOS)在异氟醚延迟相预处理心肌保护中的作用。方法新西兰白兔36只随机分成五组:异氟醚预处理组(n=9),异氟醚持续吸入2h;1400Wa组(n=6),给予选择性iNOS阻滞药1400W;1400Wb组(n=6),于缺血-再灌注前30min给予1400W;异氟醚 1400W组(n=6),给予异氟醚持续吸入2h,在缺血-再灌注前30min给予1400W;对照组(n=9),给予生理盐水。各组建立心肌局部缺血-再灌注模型。监测缺血-再灌注期间血流动力学参数,测定心肌梗死范围,检测iNOS基因水平表达和蛋白表达。结果异氟醚预处理组[(23.98±2.65)%]和对照组[(42.14±3.06)%]相比明显减少心肌缺血-再灌注后心肌梗死范围(P<0.01),异氟醚 1400W组[(42.12%±2.60)%]和异氟醚预处理组相比,1400W可以取消异氟醚的减少心肌梗死范围的作用(P<0.01)。iNOS在基因水平和蛋白表达水平均增加。结论异氟醚延迟相预处理具有抗心肌缺血-再灌注损伤的作用,而且这种作用是由iNOS所介导。     

靶向大鼠诱导型一氧化氮合酶基因的shRNA重组腺病毒载体的构建及鉴定

目的 构建携带增强型绿色荧光蛋白基因(EGFP)标志针对大鼠诱导型一氧化氮合酶(iNOS)基因的shRNA重组腺病毒载体并在人胚肾-293细胞中扩增制备重组病毒.方法 利用AdMax包装系统,用先期构建的带有EGFP标记基因的穿梭质粒pDC316-iNOS-shRNA-EGFP,与骨架质粒pBHGlox_El,3Cre共转染293包装细胞,同源重组产生复制缺陷型重组腺病毒载体Ad5-inosshRNA-EGFP,反复感染293细胞扩增病毒后,离子交换法纯化病毒,并测定病毒颗粒数及滴度.结果 经聚合酶链反应(PCR)检测和EGFP表达证明已成功构建了携带iNOS-shRNA-EGFP的重组腺病毒载体;扩增纯化后,测得重组腺病毒颗粒数为3.6×1011 VP/ml,A260/A280值约为1.25,病毒活性为7.94×109IU/ml.结论 已成功构建重组腺病毒载体Ad5-inos-shRNA-EGFP,为利用基因激活技术治疗勃起功能障碍的研究奠定实验基础.

Abstract：

Objective To construct an adenovirus vector expressing short hairpin RNA (shRNA)of rat inducible oxide synthase (iNOS) carrying enhanced green fluorescent protein (EGFP) and amplify the adenovirus vector in HEK-293 cells. Methods The shuttle plasmid pDC316-inos-shRNA-EGFP that was constructed at an earlier date, was cotransfected with the adenovirus skeleton plasmid pBHGlox_E1,3Cre into 293 cells to obtain the produced replication defective recombinant adenovirus vector Ad5-inosshRNA-EGFP. The recombinant adenovirus was propagated by repeat infection of 293 cells and purified by ion exchange method, then the virus particles were counted and the purity and titer were determined.Results Recombinant adenoviral vector Ad-ACE-shRNA was constructed successfully, which was confirmed by polymerase chain reaction (PCR) and GFP expression. After amplification and purification, the virus particle count, A260/A280 and titer of recombinant adenovirus were 3.6 × 1011 VP/ml, 1.25 and 7.94 ×109 IU/ml,respectively. Conclusion Recombinant adenovirus vector Ad5-inos-shRNA-EGFP is successfully constructed, which laid a foundation for gene activation in erectile dysfunction treatment.     

一氧化氮及一氧化氮合酶与吗啡耐受关系的新进展

疼痛治疗中长期给予吗啡易导致严重的耐受问题.多年来,针对耐受机制的研究表明NMDA/NO级联反应参与耐受的发生及发展.一氧化氮(nitric oxide,NO)主要是由一氧化氮合酶(nitric oxide synthase,NOS)催化其惟一前体--L-精氨酸生成NO和瓜氨酸.研究者们证实了大鼠鞘内吗啡耐受后脊髓内NOS尤其是nNOS的表达增高,耐受机制主要通过N-甲基-天门冬氨酸(N-methyL-D-aspartate,NMDA)受体的激活以及胞内钙离子浓度的升高来调节NOS的活性而触发NMDA/NO级联反应,继而影响耐受的发展.诸多研究给予吗啡的同时给予NOS抑制剂可以阻止耐受的发生,甚至在耐受形成后应用NOS抑制剂也可以翻转已经建立的耐受.但证实NOS各亚型在耐受中的具体作用仍不明确,需开展相关的研究进一步阐述其间的关系.     

抗氧化剂抑制内毒素性休克大鼠诱导型一氧化氮合酶基因表达

感染性休克时循环机能障碍的显著特点表现为进行性、顽固性低血压,伴对血管活性药物敏感性降低,以至组织器官灌注不足、重要器官机能代谢障碍,病死率仍高达30％～70％。休克时循环机能障碍所涉及的病理生理机制极其复杂,脂质过氧化物的堆积和NO的爆发生成是其中的关键病理因素之一。我们以往的研究中发现抗氧化剂能部分逆转内毒素休克大鼠的血管低反应性,为了进一步探讨其治疗学机制,本实验对抗氧化剂在内毒素性休克大鼠iNOS mRNA表达中的作用进行了观察。     

洛沙坦对糖尿病大鼠肾组织一氧化氮水平的影响

目的 研究洛沙坦对糖尿病大鼠肾组织一氧化氮（NO）水平的影响。方法 雄性Wistar大鼠分为3组,A组（11只）为正常对照组,B组（11只）为糖尿病未干预组,C组（9只）为糖尿病大鼠洛沙坦干预组。以链脲菌素制备糖尿病大鼠模型,大鼠饲养18周后取出肾脏检测诱导型NO合成酶（iNOS）mRNA的表达,电镜检测大鼠肾小球基底膜厚度及系膜基质密度（系膜基质面积/系膜面积）。收集24h尿测定尿白蛋白排泄（UAE）及肌酐,并心脏内取血检测血肌酐。mRNA表达采用RT-PCR,以β-actin作为内对照。UAE测定采用大鼠白蛋白特异的酶免疫分析试剂盒。结果 肾组织iNOSmRNA表达在B组大鼠（0.30±0.12）显著高于A组（0.12±0.04,P<0.01）,C组（0.25±0.14）与B组比较差异无显著性意义（P>0.05）。肾组织NO水平在B组大鼠[（0.56±0.20）μmol/mg肾组织]显著低于A组[（1.05±0.25）μmol/mg肾组织]和C组[（1.13±0.62）μmol/mg肾组织,P均<0.01]。UAE在B组大鼠[（2.18±1.98）mg/d]显著高于A组[（0.41±0.47）mg/d]和C组[（0.65±0.89）mg/d,P均<0.05]。肌酥清除率在B组大鼠[（19.75±9.60）ml/d]显著低于A组[（59.63±22.75）ml/d]和C组[（40.88±25.57）ml/d,P均<0.05]。基底膜厚度在B组大鼠[（531.6±107.6）nm]显著高于A组[（312.4±25     

Glycyrrhizin treatment is associated with attenuation of lipopolysaccharide-induced acute lung injury by inhibiting cyclooxygenase-2 and inducible nitric oxide synthase expression

Glycyrrhizin (GL), a major active constituent of licorice root, has been attributed numerous pharmacologic effects, including anti-inflammatory, anti-viral, anti-tumor, and hepatoprotective activities. In this study, we investigated the anti-inflammatory effect of GL on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice. ALI was induced in Balb/c mice by intratracheal instillation of LPS (1 mg/kg). Before 1 h of LPS administration, the mice received intraperitoneal injection of GL at varied doses (10, 25, and 50 mg/kg). The severity of pulmonary injury was evaluated 12 h after LPS administration. GL pretreatment led to significant attenuation of LPS induced evident lung histopathologic changes, alveolar hemorrhage, and neutrophil infiltration with evidence of reduced myeloperoxidase (MPO) activity. The lung wet/dry weight ratios, as an index of lung edema, were markedly reduced by GL pretreatment. The concentrations of pro-inflammatory cytokines interleukin (IL)-1β and tumor necrosis factor (TNF)-α were elevated in bronchoalveolar lavage fluid (BALF) after LPS administration, which were significantly inhibited by GL pretreatment. GL pretreatment also reduced the concentrations of nitric oxide (NO) in lung tissues. Furthermore, the expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) was suppressed by GL pretreatment. In conclusion, GL potently protected against LPS-induced ALI, and the protective effects of GL may attribute partly to the suppression of COX-2 and iNOS expression.