参麦注射液对再灌注性大鼠心肌细胞保护的研究

目的:探讨参麦注射液对再灌注性大鼠心肌细胞保护的作用机制.方法:结扎冠状动脉前降支复制大鼠心肌缺血再灌注损伤模型,测定心肌组织丙二醛(MDA)含量及结构型、诱导型一氧化氮合酶(cNOS,iNOS)、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、血清肌酸激酶(CK)的活性.结果:参麦注射液组心肌组织cNOS、SOD、GSH-Px活性高于缺血再灌注组(P＜0.01),MDA含量、iNOS及血清CK活性低于MI/R组(P＜0.01).结论:参麦注射液保护心肌再灌注性损伤的作用与其抑制iNOS活性、激活cNOS、提高心肌抗氧化能力、清除氧自由基、减轻细胞膜脂质过氧化状态相关.     

蕲蛇酶减轻大鼠局灶性脑缺血再灌注损伤的实验研究

目的 :探讨蕲蛇酶 (acutobin)在局灶性脑缺血再灌注损伤模型中的保护作用及其机制。方法 :线栓法制备大鼠大脑中动脉闭塞 (MCAO)模型 ,缺血3h后恢复血流再灌 2 4h。观察蕲蛇酶对脑梗死面积、脑组织中髓过氧化物酶 (MPO)、诱导型一氧化氮合酶 (iNOS)活性、一氧化氮 (NO)、丙二醛 (MDA)含量和超氧化物歧化酶 (SOD)活性的影响。结果 :蕲蛇酶能有效减小脑梗死灶 ,缓解MPO升高、降低MDA含量、抑制iNOS活性 ,降低NO含量。结论 :蕲蛇酶对脑缺血再灌注损伤有保护作用 ,其机制可能与缓解MPO升高以及抑制脑组织中iNOS活性 ,降低NO、MDA含量有关     

四氢生物蝶呤对大鼠肾缺血再灌注损伤的作用

目的：探讨四氢生物蝶呤(BH4)对肾缺血再灌注损伤(IR)模型的作用及其作用机制。方法：复制大鼠肾缺血再灌注模型，手术前1h喂饲BH4，动态检测其对肾组织NO含量、cNOS和iNOS活性的影响，并通过肾功能、MPO、MDA的变化来评价BH4对肾IR模型的作用。结果：BH4能够升高再灌注早期cNOS活性，增加内皮源性NO含量，减轻炎症反应，减弱再灌注后期对iNOS的诱导作用。结论：BH4可改善再灌注初期cNOS活性，保护肾功能。     

胡黄连苷Ⅱ对脑缺血再灌注大鼠神经损伤的保护作用研究

目的研究胡黄连苷Ⅱ对大鼠脑缺血再灌注损伤的保护作用。方法采用线栓法制作大鼠大脑中动脉闭塞再灌注（MCAO/R）模型,经尾静脉注射胡黄连苷Ⅱ10、30mg/kg,以银杏叶提取物注射液为阳性药。于缺血再灌注24h后进行神经功能评分和提高躯体摆动实验（EBST）,观察病灶处病理学变化,测定脑匀浆上清超氧化物歧化酶（SOD）活性、丙二醛（MDA）含量、还原型谷胱甘肽含量、一氧化氮合酶（NOS）活性等。结果与模型组比较,胡黄连苷Ⅱ治疗组神经功能评分和对侧旋转次数水平降低,差异有统计学意义（P〈0.05或P〈0.01）;病理学研究显示病灶处皮质神经元肿胀坏死有所减轻;脑匀浆上清SOD活性和GSH含量明显升高,MDA含量显著降低（P〈0.01）;总NOS（T-NOS）、诱导型NOS（iNOS）、构建型NOS（cNOS）活性均明显降低,P〈0.01或P〈0.001。结论胡黄连苷Ⅱ可保护MCAO/R模型大鼠神经功能,该作用与胡黄连苷Ⅱ提高模型大鼠脑组织的抗氧化能力、减少脑缺血再灌注所致的氧化性损伤有关。     

缺血后适应的心肌保护作用及其对心肌血红素氧化酶-1表达的影响

目的观察新西兰大白兔缺血后适应的心肌保护作用,并对其机制进行探讨。方法采用结扎冠状动脉前降支根部行30min缺血／3h再灌注．制作缺血／再灌注模型。随机分为两组：（1）缺血再灌注组（Con组）;（2）缺血后适应组（PC组）：再灌注时行3次10s复流／10s闭合操作;每组随机抽取6只测定心肌梗死面积及测定血清CK、MPO、MDA、SOD、NOS含量：其余6只测定心肌超微结构的变化,及通过免疫组化方法观察对心脏血红素氧化酶-1（HO—1）蛋白表达的影响。结果PC组可以显著降低缺血再灌注心律失常,缩小心肌梗死面积．降低血清再灌注1h、2h、3hCK值,降低MPO、MDA活性,升高SOD、NOS活性。PC组可以显著改善心肌超微结构损伤．并可上调心肌HO-1的表达。结论缺血后适应可以产生强大的心肌保护作用,心肌HO-1表．达的上调可能与缺血后适应心肌保护作用有关。     

罗格列酮对大鼠脑缺血/再灌注损伤的保护作用

目的探讨罗格列酮对局灶性脑缺血/再灌注损伤的保护作用及其机制。方法线栓法制备大鼠大脑中动脉局灶性脑栓塞模型,缺血2h,再灌注24h。评价神经功能状态,测定脑梗死体积;分光光度法测定组织丙二醛(MDA)和一氧化氮(NO)含量以及一氧化氮合酶(NOS)、超氧化物歧化酶(SOD)和髓过氧化物酶(MPO)活性。免疫组化法测定细胞间粘附分子-1(ICAM-1)表达,HE染色观察组织病理学改变。结果罗格列酮能降低缺血再灌注后脑梗死体积,改善神经功能状态,降低脑组织MDA、NO含量,升高SOD活性并降低NOS、MPO活性以及组织ICAM-1表达,同时能减轻脑组织病理学损害。结论罗格列酮对大鼠脑缺血/再灌注损伤具有明显保护作用,其机制与其清除氧自由基和抗炎有关。     

水黄皮根乙酸乙酯萃取物对大鼠乙醇型胃黏膜损伤的保护作用(英文)

目的研究水黄皮根乙酸乙酯萃取物(PREA)对乙醇致胃黏膜损伤的治疗作用。方法建立乙醇致大鼠胃黏膜损伤模型,通过观察胃组织病理学改变、计算胃黏膜损伤指数、检测胃黏膜组织一氧化氮(NO)、丙二醛(MDA)含量和超氧化物歧化酶(SOD)活性评价PREA对乙醇型胃黏膜损伤的保护作用。采用幽门结扎模型,观察PREA对大鼠胃液分泌和胃黏液分泌的影响。结果与模型组比较,PREA可剂量依赖性地降低乙醇所致胃黏膜损伤指数,明显改善胃黏膜损伤的病理变化,抑制乙醇引起的胃黏膜MDA含量升高及NO水平和SOD活性降低,并显著减少胃酸分泌、抑制游离胃酸酸度和总酸度,对胃蛋白酶活性没有明显影响。另外,可显著抑制幽门结扎模型大鼠胃腔游离黏液以及胃壁结合黏液的分泌。结论PREA对乙醇型胃黏膜损伤具有明显的保护作用,提示PREA可能成为预防或治疗乙醇所致胃损伤的药物。     

天贞子胶囊对大鼠脑缺血再灌注损伤的保护作用

目的 观察天贞子胶囊对大鼠腩缺血再灌注损伤的保护作用.方法 采用SD大鼠大脑中动脉缺血2 h再灌注22 h模型,ig给药;采用经神经病学评分,图象分析系统测定脑梗死范围,并测定腩组织中水的含量,一氧化氮合酶(NOS)、超氧化物歧化酶(SOD)的活性和丙二醛(MDA)的含量.结果 天贞子胶囊可明显改善大鼠的脑缺血损伤症状,降低神经病学评分、脑梗死范围、脑组织中水的含量、MDA的含量、NOS的活性,并升高SOD的活性.结论 天贞子胶囊对大鼠脑缺血再灌注损伤有保护作用,作用机制与抑制NOS的活性、提高SOD的活性、减少神经细胞的脂质过氧化损伤有关.     

大鼠缺血再灌注肾组织一氧化氮合成酶mRNA表达的研究

目的 探讨大鼠缺血再灌注肾组织一氧化氮合成酶（NOS）mRNA表达的特点,分析缺血再灌注肾损伤的分子机制。方法 建立大鼠肾缺血再灌注模型。采用组织细胞原位杂交及图像分析技术对不同实验条件下各型NOS（eNOS,nNOS及iNOS)mRNA表达的定位及含量进行检测。并对肾组织NOS总活性及血肌酐（Cr)值进行生化测定。结果（1）正常情况下,eNOS,nNOS及iNOS在正常肾组织中均有表达,cNOS/iNOS比值为2.29;eNOS和nNOS主分布于肾小球及血管内皮;iNOS仅分布于皮质远,近曲小管上皮。（2）缺血时,肾组织NOS总活性显著下降,三种NOSmRNA在皮,髓质及小球中的表达均下调,以eNSO最明显,cNSO/iNOS比值降为2.01。（3）再灌注后,三种NOSmRNA的表达明显上调,以iNOSmRNA最明显,cNOS/iNOS比值降为1.77,eNOS及nNOS上调部位仅限于肾皮,髓质血管,而小球及小管中则表现为下调,尤以nNOSmRNA在小球中的下调最明显。结论 （1）缺血再灌注后,皮质肾小管上皮中iNOSmRNA的高表达是导致肾缺血再灌注损伤的重要分子机制。（2）cNOS/iN-OS比值与缺血再灌注过程中肾功能的变化密切相关,该比值的恒定对肾血流量和肾小球滤过率（GFR）的调节可能具有重要意义。     

钩藤总碱抗实验性脑缺血的作用

目的　观察钩藤总碱 (Rhynchophyllatotalalkaloids,RTA )对脑缺血损伤的影响并对其作用机制作初步探讨。方法　采用小鼠断头张口喘气模型 ,大鼠大脑中动脉缺血 2h/再灌注 2 2h模型 ,神经病学评分 ,脑梗死范围及脑组织水含量变化 ,观察对脑缺血 /再灌注损伤的影响 ;通过测定大鼠脑组织中一氧化氮合酶 (nitricoxidesynthase,NOS)、超氧化物歧化酶 (superoxidedisumtase ,SOD)活性及丙二醛 (malon dialdehyde ,MDA)含量的变化 ,并经原位末端标记法观察对脑细胞凋亡的影响以探讨药物作用的机制。结果　RTA可延长小鼠张口喘气时间 ,降低大鼠脑缺血 /再灌注后神经病学评分及梗死范围 ,降低脑组织MDA、NOS含量及升高SOD活性 ,RTA还能减少神经细胞的凋亡。结论　RTA对脑缺血 /再灌注损伤有保护作用 ,其作用与抑制NOS活性 ,提高SOD活性 ,减少神经细胞脂质过氧化损伤和抑制神经细胞凋亡有关。     

L-arginine protects against stress-induced gastric mucosal lesions by preserving gastric mucus

1. We have shown that exogenously administered L-arginine protects against water immersion restraint (WIR) stress-induced gastric mucosal lesions in rats through preservation of nitric oxide (NO) generation via constitutive nitric oxide synthase (cNOS), but not inducible nitric oxide synthase (iNOS), in the gastric mucosa. We have also indicated that impaired gastric mucus synthesis and secretion occur through a decrease in gastric cNOS activity in WIR-stressed rats. Therefore, in the presesnt study, we examined whether exogenously administered L-arginine exerts a protective effect against WIR stress-induced gastric mucosal lesions in rats through preservation of gastric mucus synthesis and secretion by NO generated from the administered amino acid via cNOS in the gastric mucosa. 2. Rats were subjected to WIR stress for 3 and 6 h. Either L-arginine (150-600 mg/kg) or D-arginine (600 mg/kg) was injected intraperitoneally 0.5 h prior to WIR stress. Either N(G)-monomethyl L-arginine (L-NMMA; 100 mg/kg) or N(G)-monomethyl D-arginine (D-NMMA; 100 mg/kg) was injected subcutaneously 0.5 h prior to WIR stress. Total NOS, cNOS, iNOS, nitrite and nitrate (breakdown products of NO), hexosamine (an index of gastric mucin) and adherent mucus were assayed in the gastric mucosa. 3. Pretreatment with L-arginine, but not D-arginine, protected against gastric mucosal lesions in rats subjected to WIR stress for 3 and 6 h in a dose-dependent manner. Pretreatment with L-arginine, but not D-arginine, attenuated decreases in hexosamine and adherent mucus concentrations and cNOS activity and increases in total NOS and iNOS activities and nitrite/nitrate concentration in the gastric mucosal tissue of rats subjected to WIR stress for 3 and 6 h in a dose-dependent manner. Both the protective effect of L-arginine against gastric mucosal lesions and the attenuating effect of the amino acid on the decreases in gastric mucosal hexosamine and adherent mucus concentrations and cNOS activity in rats subjected to WIR stress for 6 h were counteracted by cotreatment with L-NMMA, a nitric oxide synthase inhibitor, but not D-NMMA. 4. These results suggest that exogenously administered L-arginine exerts a protective effect against stress-induced gastric mucosal lesions in rats at least partly through preservation of gastric mucus synthesis and secretion by NO produced from the administered amino acid via cNOS in gastric mucosal tissue.     

Preventive effect of teprenone on stress-induced gastric mucosal lesions and its relation to gastric mucosal constitutive nitric oxide synthase activity.

Recently, we demonstrated that teprenone, an anti-ulcer agent, exerts protective and preventive actions against water immersion restraint (WIR) stress-induced gastric mucosal lesions in rats both by inhibiting neutrophil infiltration into the gastric mucosal tissue and by preserving gastric mucus synthesis and secretion. In rats with WIR stress we have also found a decrease in gastric mucosal constitutive nitric oxide synthase (cNOS) activity and a drastic increase in gastric mucosal inducible nitric oxide synthase (iNOS) activity. The decrease in gastric mucosal cNOS activity is closely related to an increase in neutrophil infiltration into the gastric mucosa and a decrease in the level of gastric mucus. In this study of WIR-stressed rats, therefore, we examined whether the inhibitory actions of teprenone on neutrophil infiltration and decreases in mucus synthesis and secretion in the gastric mucosa of rats are related to the change in gastric mucosal cNOS activity during the development of gastric mucosal lesions. Pre-administration of teprenone (200 mg kg-1) prevented the decrease in gastric mucosal cNOS activity with attenuations of neutrophil infiltration into gastric mucosal tissues and decreased levels of gastric mucosal hexosamine, an index of gastric mucin, and adherent mucus in rats with 3 or 6 h of WIR stress. These preventive effects of teprenone on the gastric mucosal neutrophil infiltration and the decrease in gastric mucus levels in rats with WIR stress were completely reversed with inhibition of gastric mucosal cNOS activity by co-administration of NG-monomethyl L-arginine (L-NMMA), a non-selective NOS inhibitor. These results suggest that the inhibitory actions of teprenone on neutrophil infiltration and decreases in mucus synthesis and secretion in the gastric mucosa of rats with WIR stress are closely related to the maintenance of cNOS activity in the gastric mucosal tissue.     

Protective effect of L-arginine against stress-induced gastric mucosal lesions in rats and its relation to nitric oxide-mediated inhibition of neutrophil infiltration.

Pretreatment with l -arginine (150-600 mg kg(-1), i.p.), but not d -arginine (600 mg kg(-1), i.p.), protected against gastric mucosal lesions in rats with water immersion restraint stress over a 6-h period. This protective effect occurred in a dose-dependent manner. Increases in the activities of inducible nitric oxide synthase (iNOS) and myeloperoxidase (MPO), an index of tissue neutrophil infiltration, and the concentration of nitrite/nitrate, breakdown products of nitric oxide, and a decrease in the activity of constitutive nitric oxide synthase (cNOS) occurred in the gastric mucosal tissue with the development of gastric mucosal lesions. The l -arginine pretreatment attenuated the increases in iNOS and MPO activities and nitrite/nitrate concentration and the decrease in cNOS activity in the gastric mucosal tissue in a dose-dependent manner, while the d -arginine pretreatment did not. Both the protective effect of l -arginine (300 mg kg(-1)) against stress-induced gastric mucosal lesions and the attenuating effect of the amino acid on the increases in gastric mucosal iNOS and MPO activities and the decrease in gastric mucosal cNOS activity with the lesion development were counteracted by pretreatment with N(G)-monomethyl- l -arginine (100 mg kg(-1), s.c.), a nitric oxide synthase inhibitor, but not its d -isomer (100 mg kg(-1), s.c.). These results suggest that the protective effect of exogenously administered l -arginine against stress-induced gastric mucosal lesions in rats is, at least in part, due to nitric oxide-mediated inhibition of neutrophil infiltration into the gastric mucosal tissue.     

Protective effect of rutin against acute gastric mucosal lesions induced by ischemia-reperfusion

Abstract

Context: Rutin, a flavonoid commonly present in onions, apples and tea, has been suggested to have a variety of pharmacological activities, including immunomodulator, anti-inflammatory and antioxidant activities.

Objectives: The present study was to examine the protective effects of rutin on gastric mucosal damage induced by gastric ischemia-reperfusion (I/R) in rats.

Materials and methods: Rutin (50, 100, 200?mg/kg) was administered intragastrically for five consecutive days before ischemia. Sixty minutes after the last administration of rutin, under anesthesia, the celiac artery was clamped for 30?min, and then the clamp was removed for 60?min reperfusion. After reperfusion, the stomach was removed for biochemical and histological examinations.

Results: As compared with the I/R group (116.7?±?21.5), administration of rutin at doses of 50, 100 and 200?mg/kg significantly prevented the increase of gastric mucosal injury index induced by gastric I/R (73.4?±?14.8, 65.9?±?9.6 and 26.9?±?5.7, respectively). ED₅₀ value was 138.7?mg/kg. Moreover, rutin at doses of 50, 100 and 200?mg/kg showed an inhibition on the increased myeloperoxidase (24.6, 41.3 and 53.1% reduction) activity and malondialdehyde levels (27.4, 40.3 and 50.7% reduction) in gastric mucosa. Also, the elevation of inducible NO synthase (iNOS) activity as well as the decrease of constitutive NO synthase (cNOS) in the gastric mucosa were significantly prevented by rutin pretreatment.

Conclusion: These results suggested that rutin has a protective effect against gastric mucosal injury induced by gastric I/R and that the gastroprotection was related to the NOS/NO pathway and its antioxidant activity.     

Protective effect of -arginine against stress-induced gastric mucosal lesions in rats and its relation to nitric oxide-mediated inhibition of neutrophil infiltration

Pretreatment with -arginine (150–600 mg kg⁻¹, i.p.), but not -arginine (600 mg kg⁻¹, i.p.), protected against gastric mucosal lesions in rats with water immersion restraint stress over a 6-h period. This protective effect occurred in a dose-dependent manner. Increases in the activities of inducible nitric oxide synthase (iNOS) and myeloperoxidase (MPO), an index of tissue neutrophil infiltration, and the concentration of nitrite/nitrate, breakdown products of nitric oxide, and a decrease in the activity of constitutive nitric oxide synthase (cNOS) occurred in the gastric mucosal tissue with the development of gastric mucosal lesions. The -arginine pretreatment attenuated the increases in iNOS and MPO activities and nitrite/nitrate concentration and the decrease in cNOS activity in the gastric mucosal tissue in a dose-dependent manner, while the -arginine pretreatment did not. Both the protective effect of -arginine (300 mg kg⁻¹) against stress-induced gastric mucosal lesions and the attenuating effect of the amino acid on the increases in gastric mucosal iNOS and MPO activities and the decrease in gastric mucosal cNOS activity with the lesion development were counteracted by pretreatment with N^G-monomethyl- -arginine (100 mg kg⁻¹, s.c.), a nitric oxide synthase inhibitor, but not its -isomer (100 mg kg⁻¹, s.c.). These results suggest that the protective effect of exogenously administered -arginine against stress-induced gastric mucosal lesions in rats is, at least in part, due to nitric oxide-mediated inhibition of neutrophil infiltration into the gastric mucosal tissue.     

Role of nitric oxide and mucus in ischemia/reperfusion-induced gastric mucosal injury in rats

The present study aims at investigating the role of nitric oxide (NO) on the oxidative damage in gastric mucosa of rats which received ischemia/reperfusion (I/R) and its relation to mucus. NO synthesis modulators such as L-arginine and N(G)-nitro-L-arginine methyl ester (L-NAME) were injected intraperitoneally to the rats 30 min prior to I/R which was induced by clamping the celiac artery and the superior mesenteric artery for 30 min and reperfusion for 1 h. As a result, I/R increased lipid peroxide production and decreased the contents of glutathione (GSH), cGMP and mucus as well as GSH peroxidase activities of gastric mucosa. I/R decreased the activity and protein of NO synthase (NOS) in gastric mucosa. Pretreatment of L-arginine, a substrate for NOS, prevented I/R-induced alterations of gastric mucosa. However, L-NAME, an NOS inhibitor, deteriorated oxidative damage induced by I/R. In conclusion, NO has an antioxidant defensive role on gastric mucosa by maintaining mucus, GSH and GSH peroxidase, which were related to preservation of cGMP and NOS in gastric mucosa.     

Involvement of nitric oxide (NO) in the mechanism of gastric preconditioning induced by short ischemia

Gastric mucosa subjected to repeated brief episodes of ischemia exhibits an increased resistance to damage caused by a subsequent prolonged ischemic insult and this is called gastric preconditioning. In this study, L-NNA, a non-selective NO-synthase inhibitor, and aminoguanidine, a relative inhibitor of inducible NO-synthase (iNOS), were applied prior to short ischemia (occlusion of celiac artery 1-5 times for 5 min) followed by a subsequent exposure to 0.5 h of ischemia and 3 h of reperfusion (I/R). Short ischemia significantly reduced the I/R-induced lesions while raising significantly the GBF and luminal NO content. These effects were attenuated by L-NNA and aminoguanidine and restored by addition of L-arginine and SNAP to L-NNA and aminoguanidine. The cNOS mRNA, but not iNOSmRNA, was detected in intact mucosa and only cNOS mRNA was strongly upregulated in the preconditioned mucosa. We conclude that overexpression of cNOS with the subsequent release of NO plays a key role in the mechanism of gastric preconditioning.     

次枸橼酸铋钾胃粘膜保护作用机制研究

目的：探讨次枸橼酸铋钾（CBS）抗溃疡作用与CBS对胃粘膜中一氧化氮（NO）含量和一氧化氮合酶（NOS）活力影响之间的关系。方法：无水乙醇诱发大鼠粘膜损伤性胃溃疡；CBS进行治疗；联苯胺荧光分光光度法测定NO含量和NOS活力。结果：CBS灌胃给药显著降低溃疡面积，并使异常升高的诱生型NOS（iNOS）活力和NO含量显著降低，并恢复到正常水平。CBS腹腔给药可显著降低胃粘膜NO含量和iNOS活力，升高原生型NOS（cNOS）活力。体外CBS可抑制NOS活力。结论：CBS胃粘膜保护作用机制可能与其降低胃粘膜中异常升高的NO含量和iNOS活力有关。     

Protective effect of (+)-catechin against gastric mucosal injury induced by ischaemia-reperfusion in rats

Ischaemia and reperfusion are known to induce gastric lesions, predominantly due to excessive formation of reactive oxygen metabolites, adhesion of neutrophils to endothelial cells, microvascular dysfunction, gastric acid secretion, endogenous histamine and gastrin release. We have studied the effect of (+)-catechin on a gastric ulcer model involving damage to gastric injury by ischaemia- reperfusion (I/R) in rats. (+)-Catechin 50 mg kg(-1)administered orally, once daily for three days after the initiation of I/R injury showed a significant (P<0.001) anti-ulcer activity against mucosal dam- age. However, (+)-catechin significantly decreased the lipid peroxidation and increased the level of catalase in the I/R condition. Elevated levels of alkaline phosphatase in the I/R group was significantly lowered (P<0.01) by (+)-catechin. The amount of H(+)K(+)ATPase was significantly decreased (P<0.001) in (+)-catechin-treated as compared with I/R rats. (+)-Catechin significantly decreased elevated plasma histamine (P<0.05) and corticosterone (P<0.05). The results suggested that (+)-catechin protected gastric mucosa against ischaemia-reperfusion-induced gastric ulcers by its antioxidant activity and mucus protection.