Effect of melatonin on altered expression of vasoregulatory genes during hepatic ischemia/reperfusion

The production of reactive oxygen species during hepatic ischemia/reperfusion (I/R) can help create disturbances in microcirculation. This study examined the effect of melatonin, a pineal secretory product and a potent antioxidant, on the expression of vascular stress genes during hepatic I/R. Rats were subjected to 60 min of hepatic warm ischemia followed by 5 h reperfusion. Melatonin (10 mg/kg) was administered intraperitoneally 15 min before ischemia and immediately before reperfusion. The serum alanine aminotransferase and hepatic malondialdehyde levels increased markedly after I/R. These increases were significantly inhibited by melatonin. The levels of endothelin-1 (ET-1) and its receptor, ET(B) mRNA, were elevated by I/R but attenuated by melatonin. The mRNA levels of endothelial nitric oxide synthase (eNOS), inducible nitric oxide synthase (iNOS), and heme oxygenase-1 were significantly higher after I/ R. Melatonin augmented the increase in the eNOS mRNA level, whereas it reduced the increase in the iNOS mRNA level. The expression of tumor necrosis factor-alpha was increased markedly by I/R. This increase was also attenuated by melatonin. These results suggest that melatonin ameliorates the imbalanced expression of the vascular stress genes during hepatic I/R through its antioxidant property.     

Antioxidant and prooxidant properties of ascorbic acid on hepatic dysfunction induced by cold ischemia/reperfusion

Oxidative stress, which has been generated during reperfusion after a liver transplant, has been implicated in the higher rates of postoperative organ dysfunction. The aim of this study was to examine the effect of ascorbic acid on reperfusion injury after hepatic cold preservation. Isolated perfused rat livers were preserved in a University of Wisconsin solution for 30 h at 4 °C. The bile output was significantly lower after cold ischemia/reperfusion. In contrast, the portal pressure, lactate dehydrogenase and purine nucleoside phosphorylase activities were elevated by cold ischemia/reperfusion. These changes were attenuated at ascorbic acid concentrations of 0.25 and 0.5 mM. However, they were augmented at a concentration of 2 mM. Cold ischemia/reperfusion decreased the reduced to oxidized glutathione ratio, whereas it increased the level of lipid peroxidation and mitochondrial swelling. These changes were prevented exposing the liver to 0.5 mM ascorbic acid but were augmented at 2 mM ascorbic acid. These results suggest that cold ischemia/reperfusion injury is associated with a higher level of oxidative stress and ascorbic acid may act not only as an antioxidant but also as a prooxidant during cold ischemia/reperfusion.     

依达拉奉对培养乳鼠海马神经元缺血再灌注损伤的保护作用

目的:探讨依达拉奉对海马神经元缺血再灌注损伤的保护作用及其机制.方法:原代培养海马神经元细胞,制成缺血再灌注损伤模型,分别用 1 μmol·L-1、10 μmol·L-1、100 μmol·L-1、300 μmol·L-1 依达拉奉干预后,在细胞水平上研究依达拉奉对脂质过氧化、线粒体膜电位以及细胞内钙离子浓度的作用.结果:海马神经元在缺血再灌注损伤后,依达拉奉干预均能有效地降低脂质过氧化产物丙二醛含量,增加细胞内超氧化物歧化酶活性.与正常细胞相比,缺血再灌注损伤后,海马神经元的线粒体膜电位降低了60%,加入 100 μmol·L-1和 300 μmol·L-1依达拉奉可以显著提高损伤海马神经元的线粒体膜电位,达到正常神经元线粒体膜电位的82% 和87%.与正常对照组比较, 缺血再灌注损伤组细胞内钙离子浓度增加了81%.依达拉奉 100 μmol·L-1、300 μmol·L-1组的胞内钙离子浓度分别降低了35%和36%.结论:海马神经元缺血再灌注损伤后,依达拉奉具有清除氧自由基、抑制脂质过氧化、稳定线粒体膜电位及降低细胞内钙离子浓度的作用.     

Effect of silymarin on biochemical parameters of oxidative stress in aged and young rat brain

Silymarin (SM), the active complex of milk thistle, is a lipophilic fruit extract and is composed of several isomer flavonolignans. Flavonoids are antioxidants found molecules capable of intercepting reactive oxygen species (ROS). The oxidative stress (OS) is caused by imbalance between antioxidant defenses and production of ROS causing oxidative damage to macromolecules. Brain is susceptible to oxidative stress and it is associated with age-related brain dysfunction. This study evaluated the effect of SM on biochemical parameters that evaluate OS in aged and young rat brain. For measures of OS were used measures of total oxyradical scavenging capacity (ACAP) through the concentration of ROS by fluorescence, lipid peroxidation (LPO), via FOX and TBARS, proteins oxidation by Western blot (WB). Rats were treated with SM at doses of 200 and 400 mg/kg/day (SM200 and SM400). The LPO analyzed through FOX was increased in the hippocampus of aged animals treated with SM400, but in the cortex of young and aged, the highest dose of SM decreased LPO analyzed through TBARS. Both doses have seemed most effective in the reduction of oxidized proteins in aged brain. These results suggest that SM may contribute to the prevention of aged-related and pathological degenerative processes in the brain.     

蛇床子素对肾脏缺血-再灌注损伤的作用研究

目的探讨蛇床子素对肾脏缺血-再灌注损伤(Renal ischemia reperfusion injury,IRI)的作用及其机制。方法通过夹闭左侧肾蒂并切除右肾的方法构建大鼠IRI模型。观察各组尿素氮(BUN)、血清肌酐(Cr)、肾脏病理形态、肿瘤坏死因子α(TNF-α)、单核细胞趋化蛋白-1(MCP-1)和白细胞介素-6(IL-6)、丙二醛(MDA)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GPx)和超氧化物歧化酶(SOD)的表达,评估蛇床子素对大鼠肾脏缺血-再灌注损伤的作用。结果蛇床子素可增加CAT、GPx和SOD表达,减少Cr、BUN、MDA、TNF-α、M CP-1和IL-6的表达以及肾脏病理形态的改变。结论蛇床子素可通过抑制炎症和氧化应激反应而减轻肾脏缺血-再灌注损伤。     

Oxidative damage on lymphocyte membranes is increased in patients suffering from acute carbon monoxide poisoning

Increased oxidative damage seems to be a relevant mechanism in the pathophysiology of patients with an acute carbon monoxide (CO) poisoning. We have investigated the degree of membrane oxidative damage through the assessment of lipid peroxidation in circulating lymphocytes from five patients acutely intoxicated by CO. Since mitochondria are a major source of reactive oxygen species and mitochondrial cytochrome c oxidase (COX) has been reported to be inhibited after acute CO poisoning, we have also assessed the lymphocyte COX activity and its relationship with the degree of lipid peroxidation. Data were compared with those from 32 non-smoker healthy controls comparable in terms of age, gender and physical activity. In intoxicated patients, we have found a significant increase of lipid peroxidation compared to control individuals (P<0.05), as well as a marked COX inhibition (P<0.001). Both parameters showed a positive, nearly significant correlation (r=0.81, P=0.09). We conclude that oxidative damage of lymphocyte membranes is increased after acute CO poisoning, and suggest that such increase could be partially mediated by mitochondrial COX inhibition caused by CO.     

Therapeutic potential of cannabidiol against ischemia/reperfusion liver injury in rats

The therapeutic potential of cannabidiol, the major non-psychotropic Cannabis constituent, was investigated in rats exposed to ischemia/reperfusion liver injury. Ischemia was induced by clamping the pedicle of the left hepatic lobe for 30 min, and cannabidiol (5 mg/kg, i.v.) was given 1 h following the procedure and every 24 h thereafter for 2 days. Ischemia/reperfusion caused significant elevations of serum alanine aminotransferase and hepatic malondialdehyde, tumor necrosis factor-α and nitric oxide levels, associated with significant decrease in hepatic reduced glutathione. Cannabidiol significantly attenuated the deterioration in the measured biochemical parameters mediated by ischemia/reperfusion. Histopathological examination showed that cannabidiol ameliorated ischemia/reperfusion-induced liver damage. Immunohistochemical analysis revealed that cannabidiol significantly reduced the expression of inducible nitric oxide synthase, cyclooxygenase-2, nuclear factor-κB, Fas ligand and caspase-3, and increased the expression of survivin protein in ischemic/reperfused liver tissue. These results emphasize that cannabidiol represents a potential therapeutic option to protect the liver against hypoxia–reoxygenation injury.     

Binding pattern and toxicological effects of lectins from genus Canavalia on bovine sperm

The aim of this study was to determine the binding patterns of Canavalia ensiformis (ConA), Canavalia boliviana (ConBol) and Canavalia brasiliensis (ConBr) lectins to bovine sperm and their effects on sperm motility, viability, lipid peroxidation, reactive oxygen species production and fertilization ability. ConA bound to whole spermatozoa, with the exception of the equatorial segment, ConBol did not interact with the acrosome region and ConBr exhibited a fragmented binding pattern. The three lectins decreased sperm motility but did not affect cell viability or lipid peroxidation. Nevertheless, ROS production was increased in comparison to controls and a reduction in the cleavage and blastocyst ratio was induced in comparison to controls. In conclusion, this study determined that structurally similar lectins interact differently with bovine sperm and affect sperm motility, viability, lipid peroxidation, ROS production and fertilization ability in various ways.     

Xanthone对实验性脑缺血再灌注损伤的作用机制

分别以５０ｍｇ．ｋｇ＾－１和１０ｍｇ．ｋｇ＾－１的１,８－ｄｉｈｙｄｒｏｘｙ,３,５－ｄｉｍｅｔｙｈｏｘｙｘａｎｔｈｏｎｅ（ＸＴ）给大鼠静脉给药３ｄ,探讨其对实验性脑缺血再灌注损伤的保护作用及机理;实验结果显示。ＸＴ明显减轻缺血再灌注引起的大鼠脑水肿,减少大脑皮层ＭＤＡ含量,提高ＣＡＴ和ＳＯＤ活性,提高ＧＳＨ含量,并使皮层的ＡＴＰ含量增多,乳酸含量降低。     

珠子参总皂苷对大鼠心肌缺血／再灌注损伤的保护作用及机制研究

目的：研究珠子参总皂苷预处理对大鼠心肌缺血再灌注损伤（Myocardiumischemia／Reperfusioninjury,MI／RI）的保护作用及可能的作用机制。方法：实验大鼠随机分为假手术组、缺血／再灌注模型组、珠子参总皂苷100和200mg／kg组。治疗组各组大鼠分别给予相应的药物,给药7d后,行冠状动脉结扎术,结扎30rain后,再灌注24h。记录再灌注后30min内心律失常发生情况,24h后进行血流动力学测定,然后取血进行乳酸脱氢酶（LDH）、肌酸激酶（CK）、超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH—Px）、丙二醛（MDA）和过氧化氢酶（CAT）含量分析;心脏经TTC染色和HE染色,计算心肌梗死面积和心肌组织形态学观察。实时定量PCR检测SOD／GPX／CAT反应系统SODl～SOD3、GPXl和CAT基因表达,Westernblot检测细胞质和细胞核Nrf2蛋白表达。结果：珠子参总皂苷（100、200mg／kg）可显著降低心律失常发生率（P〈0．01）,能明显改善心功能,降低血液中CK、LDH含量和MDA水平,增加SOD、GSH—Px、CAT酶的活性;减轻ROS所致心肌氧化应激损伤,降低心肌梗死面积（P〈0．05,P〈0．01）和改善心脏组织形态学;上调SOD／GPx／CAT反应系统基因表达水平和促进Nrf2核移位,增加心肌细胞核内Nrf2的表达水平（P〈0．01）。结论：珠子参总皂苷对MI／RI具有较好的保护作用,激活Nrf2抗氧化途径和抗脂质过氧化可能是其作用机制之一。     

Influence of polyphenolic extracts from Enydra fluctuans on oxidative stress induced by acephate in rats

Acephate, an organophosphorus pesticide, has been proved to play an important role in tissue damage by inducing oxidative stress through the release of free radicals. The aim of this study was to evaluate the protective effect of the plant phenolic compounds present in Enydra fluctuans against acephate toxicity based on lipid peroxidation and antioxidant enzymes profile in rats. An oral dose of acephate at 30 mg/kg of body weight has been given against the extracts containing 20 mg of polyphenolic compounds (expressed as gallic acid equivalents)/kg body weight for 14 days. The results showed that under the influence of the pesticides, there was significant decrease in the activities of the antioxidant enzymes SOD, Catalase and Glutathione peroxidase (GPx) and an increase in the non-enzymatic Glutathione, with respect to the normal and the plant extract gavaged groups. Also that there was an increase in the plasma and erythrocyte membrane lipid peroxidation levels in the pesticide treated group compared to the normal or the group treated with the plant extract. The present study thus gives an insight into the ill-effects of this organophosphate and the protective role of plant polyphenols in minimizing those effects.     

Betaine supplementation protects against renal injury induced by cadmium intoxication in rats: Role of oxidative stress and caspase-3

Cadmium (Cd) is an environmental and industrial pollutant that can induce a broad spectrum of toxicological effects that affect various organs in humans and experimental animals. This study aims to investigate the effect of betaine supplementation on cadmium-induced oxidative impairment in rat kidney. The animals were divided into four groups (n = 10 per group): control, cadmium, betaine and betaine + cadmium (1) saline control group; (2) cadmium group in which cadmium chloride (CdCl₂) was given orally at a daily dose of 5 mg/kg body weight for four weeks; (3) betaine group, in which betaine was given to rats at a dose of 250 mg/kg/day, orally via gavage for six weeks; (4) cadmium + betaine group in which betaine was given at a dose of 250 mg/kg/day, orally via gavage for two weeks prior to cadmium administration and concurrently during cadmium administration for four weeks. Cadmium nephrotoxicity was indicated by elevated blood urea nitrogen (BUN) and serum creatinine levels. Kidneys from cadmium-treated rats showed an increase in lipid peroxidation measured as thiobarbituric acid-reactive substances (TBARS) concentration and reductions in total antioxidant status (TAS), reduced glutathione (GSH) content, glutathione peroxidase (GSH-Px) activity, superoxide dismutase concentration (SOD) and catalase activity. Caspase-3 activity, a marker of DNA damage was also elevated in renal tissues of cadmium-treated rats. Pre-treatment of rats with betaine substantially attenuated the increase in BUN and serum creatinine levels. Betaine also inhibited the increase in TBARS concentration and reversed the cadmium-induced depletion in total antioxidant status, GSH, GSH-Px, SOD and catalase concentrations in renal tissues. Renal caspase-3 activity was also reduced with betaine supplementation. These data emphasize the importance of oxidative stress and caspase signaling cascade in cadmium nephrotoxicity and suggest that betaine pretreatment reduces severity of cadmium nephrotoxicity probably via antioxidant action and suppression of apoptosis.     

不稳定性心绞痛患者体内P-选择素的变化及意义

目的 探讨P-选择素在不稳定性心绞痛（UA）发生、发展中的作用,以及与脂质代谢、氧化应激的相关性.方法 选择病例组冠心病（CHD）患者68例,包括稳定性心绞痛（SA）患者20例,UA患者48例,对照组正常人20例,分别测定血浆和血小板内P-选择素含量以及血脂（血清TC、TG、LDL-C、HDL-C）、超氧化物歧化酶（SOD）、丙二醛（MDA）含量,同时分析P-选择素与血脂、脂质过氧化物的相关性.结果 UA患者血浆及血小板内P-选择素含量均显著高于SA患者和正常对照者（均P＜0.01）,而SA患者血浆及血小板内P-选择素含量与正常对照组相比差异无统计学意义（P＞0.05）.血浆P-选择素与血小板P-选择素、TG、LDL-C、MDA水平成明显正相关（均P＜0.01）,而与SOD水平成明显负相关（P＜0.01）.结论 UA患者体内P-选择素含量明显升高,提示血小板活性增强,其原理可能与脂质代谢紊乱以及氧化应激增强有关.     

Protect effect of bicyclol on cisplatin-induced nephrotoxicity in mice

This study investigated the protective effects of bicyclol against cisplatin-induced nephrotoxicity and the possible mechanisms in mice. Bicyclol (250 mg/kg, p.o., 5 days) showed significant protection as evidenced by the decrease of elevated serum creatine and blood urea nitrogen, and improvement of histopathological injury induced by cisplatin. The formation of kidney malondialdehyde with a concomitant reduction of reduced glutathione were also inhibited by bicyclol, while the activities of kidney superoxide dismutase, catalase and glutathione peroxidase were all increased, respectively. Bicyclol also inhibited the increase of kidney and serum nitric oxide induced by cisplatin. In addition, induction of induced nitric oxide synthase and nitrotyrosine were suppressed by bicyclol. Bicyclol suppressed cisplatin-induced extracelluar signal regulated kinases 1/2 and p38 mitogen-activated protein kinase activation in the kidney of mice. Results obtained demonstrate that bicyclol pre-administration can prevent the nephrotoxicity induced by cisplatin.     

葛根素预处理在大鼠肝脏缺血再灌注损伤中的抗氧化作用

目的观察葛根素预处理对大鼠肝脏缺血再灌注损伤的防护作用。方法雄性SD大鼠,建立肝脏缺血再灌注模型（HIR）。随机分为假手术组、HIR组和HIR-葛根素预处理组。黄嘌呤氧化酶法、硫代巴比妥酸比色法分别测定肝组织中丙二醛（MDA）含量和超氧化物歧化酶（SOD）活性的变化,同时分析NO含量的改变。结果肝脏缺血再灌注损伤后,与假手术组比较,肝组织中MDA活性及NO含量均显著增加,而SOD活性显著降低;经40mg/kg剂量的葛根素预处理7d后,与模型组相比,肝组织中MDA活性及NO含量显著降低,而SOD活性增高。结论葛根素预处理对大鼠缺血再灌注肝脏损伤有一定的保护作用。     

Dose- and time-dependent effects of sulfur mustard on antioxidant system in liver and brain of rat

This study investigates the dose- and time-dependent effects of sulfur mustard (SM) on antioxidant system and lipid peroxidation in liver and brain of rats. For this purpose, male Wistar rats were randomly divided into eight groups and treated as follows: group 1 as control and groups 2-8 as experimental groups that received SM (1-80 mg/kg) through intraperitoneal injection. Rats were killed after 2, 7 and 14 days of exposure. SM dose-dependently decreased body weight. Superoxide dismutase (SOD), catalase (CAT) and glutathione S-transferase (GST) activities in liver were significantly increased at SM doses lower than 10 mg/kg after 2 and 7 days of exposure. However, the recovery of these parameters was observed after 14 days. At these concentrations, no significant change in glutathione (GSH) and malondialdehyde (MDA) levels were observed. At doses higher than 10 mg/kg, SM significantly decreased SOD, CAT, glutathione peroxidase (GPX), and GST activities in liver and brain and decreased glutathione reductase (GR) activity in liver, which was associated with a depletion of GSH and increased MDA level. Present data indicate that the effect of SM is dose- and time-dependent and at higher doses (>10 mg/kg) induces an oxidative stress response by depleting the antioxidant defense systems and increasing lipid peroxidation in liver and brain of rats.     

含血停搏液对未成熟心肌缺血-再灌注损伤的实验研究

目的观察冷血浆停搏液对未成熟心肌缺血-再灌注损伤的保护作用。方法选择14～26日龄日本大耳白兔20只,建立Langendorff离体心脏灌注模型。随机抽取4只作为正常对照组(C组),其余16只随机均分为冷血浆组(P组)和冷血组(B组)。C组灌注10minK-H液终止灌注,取右室心肌做检测用。P组、B组降温同时开始分别灌注冷血浆停搏液和冷血停搏液(4℃)15mL/kg,低温(10℃)停搏30min开始复温,再灌注37℃K-H液10min后,采集、处理和保存右室心肌标本。TUNEL法测定心肌细胞凋亡。RT-PCR检测Bcl-2mRNA,行半定量分析。结果C组心肌组织凋亡率为0,P组和B组均出现心肌细胞凋亡,P组凋亡率低于B组(P<0.05)。缺血-再灌注损伤可以使心肌组织中Bcl-2mRNA表达减弱,B组Bcl-2mRNA表达减弱更为明显,P组、B组分别与对照组比较,有显著性差异(P<0.05,P<0.01)。结论未成熟心肌缺血-再灌注伴有细胞凋亡。冷血停搏液、冷血浆停搏液对未成熟心肌缺血均具有保护作用,而冷血浆停搏液作用更为明显。     

Role of melatonin in reducing hypoxia-induced oxidative stress and morphological changes in the liver of male mice

Oxygen deficiency during critical illness may cause profound changes in cellular metabolism and subsequent tissue and organ dysfunction. Thus, the present study was designed to determine the effects of hypoxia and reoxygenation on the levels of lipid peroxidation and the morphological changes in the liver of male mice as well as the protective role of melatonin as an antioxidant. Two experiments were carried out in this study. Experiment I includes three groups of mice (control, hypoxic, and hypoxic + melatonin) while the experiment II includes two groups (reoxygenated and reoxygenated + melatonin). The levels of oxidized lipids were measured and the morphological changes were investigated using light and electron microscopy. In experiment I, hypoxia strongly stimulated lipid peroxidation levels (88%) while melatonin administration inhibited this increase (69%). Severe morphological changes (necrosis, dilated congested blood vessels, collection of inflammatory cells, condensed heterochromatic with irregular outlines nuclei, and mitochondrial degeneration) were detected in the liver of hypoxic mice. In experiment II, reoxygenation inhibited the levels of oxidized lipids (42%) versus hypoxic mice and some morphological changes were detected. When melatonin was given before reoxygenation, it inhibited the levels of lipid peroxidation by 66% versus hypoxic mice. Also, melatonin enhanced the recovery profile by 41% when compared with mice that reoxygenated with room air only. All morphological alterations that detected in both hypoxic and reoxygenated mice were repaired when melatonin administered. These results indicate that hypoxia and reoxygenation induce severe alterations in the liver and that melatonin exerts beneficial role in restoring tissue alterations after subjection to hypoxia.