Effects of polyhemoglobin-antioxidant enzyme complex on ischemia-reperfusion in kidney

INTRODUCTION: The kidney suffers ischemia-reperfusion (I/R) injury during transplantation. The purpose of the present study was to investigate the therapeutic effect of artificials cells on renal I/R injury through biochemical assays and histological examination. METHODS: We prepared artificial cells using cross-linked hemoglobin (Hb), superoxide dismutase (SOD), and catalase. Normal male Sprague-Dawley rats were divided into 6 groups: the sham-operated control group, the group treated with polyHb,and the group treated with polyHb-SOD-catalase (PSC) (per groups were subjected to ischemia for 1 hour or 2 hours). After reperfusion for 4 hours, kidney and blood samples were obtained. RESULTS: The levels of SOD and catalase in the PSC group were 15 and 50 times higher than those of the control group, respectively. In the polyHb group, the levels of blood urea nitrogen (BUN), serum creatinine, renal hydrogen peroxide, and renal malondialdehyde were increased. However, their levels were significantly decreased by PSC administration. Renal SOD activity did not show any significant changes in the polyHb group, but renal catalase activity was decreased by polyHb treatment in comparison with the control group. The activities of renal SOD and catalase were increased using PSC treatment. In the histological findings, the PSC group showed no evidence of acute tubular necrosis in proximal convoluted tubules; their microvilli and cytoplasmic microorganelles were relatively well preserved. CONCLUSIONS: These results show that PSC effectively reduces renal damage via diminished oxygen free radical-mediated injury after I/R.     

Hesperidin Ameliorates Hepatic Ischemia-Reperfusion Injury in Sprague-Dawley Rats

ObjectiveHepatic ischemia and reperfusion (I/R) is a destructive event associated with high rates of liver failure after liver transplantation. Hesperidin significantly contributes to the antioxidant defense system and has been reported to act as a powerful agent against superoxide and hydroxyl radicals. Our objective was to investigate the protective effect of hesperidin against hepatic IR injury in a rat model.MethodsWe fed Sprague-Dawley rats either hesperidin (100 mg/kg/d) or saline. One week later, ischemia was induced by clamping the rats’ common hepatic artery and portal vein for 30 minutes. The rats were divided into 3 groups: 1. the sham operated group; 2. the I/R group; and 3. the I/R-hesperidin group.ResultsCompared to the sham group, the I/R group had higher expression of serum aspartate aminotransferase and serum alanine aminotransferase and lower expression of catalase, superoxide dismutase, glutathione peroxidase, antioxidant, nitric oxide, and albumin. Compared to the I/R group, the I/R-hesperidin group had higher expression of catalase, superoxide dismutase, antioxidant and nitric oxide and lower expression of serum aspartate aminotransferase and serum alanine aminotransferase.ConclusionsOur findings suggest that hesperidin is a potential therapeutic agent for hepatic I/R injury.     

姜黄素对大鼠肝缺血再灌注早期肝组织中氧自由基生成的影响

目的探讨姜黄素对大鼠肝脏缺血再灌注早期损伤的氧自由基生成的影响。方法将大鼠随机分为假手术组、对照组（肝血流阻断前30min和再灌注开始时经肠系膜上静脉各注入二甲基亚砜1ml）和实验组（姜黄素40mg／kg溶于二甲基亚砜1ml注入,余同对照组）。通过检测再灌注早期1、3h血清转氨酶水平、组织病理学改变及肝组织中超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、丙二醛（MDA）的含量来评价姜黄素对大鼠肝脏缺血再灌注早期损伤氧自由基生成的影响。结果姜黄素可降低大鼠肝脏缺血再灌注早期1、3h血清转氨酶水平,可增加肝组织中SOD、CAT含量,降低肝组织中MDA含量。结论姜黄素可通过减少肝组织氧自由基生成,减少肝缺血再灌注肝实质细胞的受损。     

The effects of allopurinol in hepatic ischemia and reperfusion: experimental study in rats

BACKGROUND/AIMS: Some studies have shown that postischemic hepatic dysfunction is mainly due to oxygen free radicals that are generated by xanthine oxidase. The present study was undertaken to determine the effect of allopurinol, an inhibitor of xanthine oxidase, on oxidative stress, liver injury and histologic alterations induced by hepatic ischemia-reperfusion in rats. METHODS: One hundred and sixty Wistar rats were used and divided into three groups. Group 1: sham operation; group 2: 50 min of ischemia followed by 1 h of reperfusion, and group 3: pretreatment with allopurinol and 50 min of ischemia followed by 1 h of reperfusion. The effect of allopurinol was evaluated by plasma levels of alanine aminotransferase and aspartate aminotransferase, histopathologic studies, and lipid peroxidation measured by the thiobarbituric acid reactive substances method and chemiluminescence initiated by tert-butyl hydroperoxide technique. RESULTS: Ischemia followed by reperfusion promoted an increase in lipid peroxidation of the hepatic cells when compared to the sham-operated group (p<0.05). This increase was attenuated in the group treated with allopurinol (p< 0.05). Allopurinol also showed a protective effect on hepatocellular necrosis (p<0.05), and the plasma levels of liver enzymes returned earlier to the normal range in rats pretreated with allopurinol in comparison to those that did not receive the drug (p<0.05). CONCLUSIONS: Allopurinol exerted a protective effect on hepatic ischemia and reperfusion in rats. The administration of this drug prior to liver operations should be considered to be submitted to trials in humans.     

Pulmonary reperfusion injury: evidence for oxygen-derived free radical mediated damage and effects of different free radical scavengers

Blood granulocyte-mediated reactions involving generation of oxygen-derived free radicals have recently been shown to be capable of causing injury to the lungs. These findings suggest a similar mechanism also to be involved in the development of pulmonary ischemia/reperfusion injury. In the present study, therefore, the effects of three oxygen-derived free radical scavengers, superoxide dismutase (SOD; 1 mg/kg), catalase (20000 IU/kg) and allopurinol (45 mg/kg), were evaluated during reperfusion in a rabbit model after 2 h normothermic ischemia of the lung. During reperfusion, ischemic lungs were found to have an elevated pulmonary vascular resistance, increased total and extravascular lung water content, and decreased arterial oxygen tension (PaO₂) compared to control animals. SOD and catalase, but not allopurinol, were able to reduce pulmonary injury by lowering the pulmonary vascular resistance, but could not prevent pulmonary damage as shown by total lung water (TLW) or PaO₂. It is concluded that oxygen-derived free radicals such as hydrogen peroxide and the superoxide anion may play an important role in precipitating pulmonary injury after ischemia. The failure of xanthine oxidase inhibition (allopurinol) to exert protective effects may suggest that oxygen-derived free radical generation following pulmonary ischemia occurs predominantly via leukocyte-mediated reactions.     

缺血后处理对大鼠肝脏缺血再灌注损伤细胞凋亡的影响

目的：探讨缺血后处理对缺血再灌注损伤大鼠肝脏细胞凋亡的影响。方法：建立大鼠局部肝脏缺血再灌注模型．将24只健康雄性Wistar大鼠随机分为假手术(S)、缺血再灌注(IR)、缺血后处理(IPo)3组，以缺血再灌注前反复多次的短暂预再灌注及停灌注作后处理，观察血清肝酶和肝组织中丙二醛(MDA)、超氧化物歧化酶(SOD)、谷胱甘肽(GSH)水平变化，用末端脱氧核苷酸转移酶介导的dUTP缺口末端标记法(TUNEL)及透射电镜观察肝细胞凋亡状态．并行肝组织病理形态学检查。结果：与IR组相比，IPo组血清肝酶水平及肝组织中MDA含量显著降低，而SOD和GSH活性则显著升高；再灌注后可见明显的肝实质细胞凋亡现象，IPo组凋亡指数较IR组显著下降，肝组织病理形态学损伤亦明显减轻。结论：IPo可通过抑制再灌注后氧自由基的过量生成而拮抗肝实质细胞凋亡的发生，从而减轻肝脏缺血再灌注损伤。     

氧自由基在肝脏保存再灌注损伤中的作用及丹参的保护作用

目的 探讨氧自由基在肝脏保存再灌注损伤（ｈｅｐａｔｉｃ ｐｒｅｓｅｒｖａｔｉｏｎ ｒｅｐｅｒｆｕｓｉｏｎ ｉｎｊｕｒｙ,ＨＰＲＩ）中的作用及丹参的保护作用。方法 建立大鼠肝脏保存再灌注模型,分别检测肝脏保存０、８、１６、２４、３２小时组在不同灌注时间点组织超氧化物酶（ＳＯＤ）、丙二醛（ＭＤＡ）和灌注液俗 草转氨酸（ＡＳＴ）的变化,并观察肝细胞形态学的改变。结果 与正常组（保存０小时组）比较,保存１     

Delivery of antioxidative enzyme genes protects against ischemia/reperfusion-induced liver injury in mice.

Hepatic ischemia/reperfusion (I/R) injury is characterized by the generation of reactive oxygen species (ROS), such as superoxide anions and hydrogen peroxide. The aim of this study is to investigate whether antioxidative gene delivery by our polylipid nanoparticles (PLNP) is an effective approach for prevention of the injury. Polyplexes of extracellular superoxide dismutase (EC-SOD) and/or catalase genes were injected via the portal vein 1 day prior to a warm I/R procedure in mice. The effects of the gene delivery were determined 6 hours after starting reperfusion. PLNP-mediated antioxidative gene delivery led to a marked increase in human EC-SOD and catalase gene expression in the liver. Liver superoxide dismutase (SOD) and catalase activity both increased approximately 10-fold. Increased liver superoxide anion levels caused by the I/R procedure were reduced to normal levels by EC-SOD gene delivery. The overexpression of these 2 antioxidative genes significantly suppressed the I/R-induced elevation of serum alanine aminotransferase (ALT) levels, decreased liver malondialdehyde content, restored glutathione reserve, and improved liver histology. In conclusion, EC-SOD or catalase gene delivery by PLNP resulted in high levels of the transgene activity in the liver, and markedly attenuated hepatic I/R injury. The protection is directly associated with elevated antioxidative enzyme activity as the result of the gene delivery. This novel approach may become a potential therapy to improve graft function and survival after liver transplantation.     

Reperfusion liver injury-induced superoxide dismutase and catalase expressions and the protective effects of N-acetyl cysteine

AIM: Reperfusion of the ischemic liver results in the generation of oxygen radicals. In this study, we analyzed if the mRNA and protein expressions of superoxide dismutase (SOD) and catalase increased after ischemia (I) and reperfusion (R) of the rat liver. MATERIALS AND METHODS: Ischemia was induced by clamping off the common hepatic artery and portal vein of rats for 40 minutes, which were then reperfused for 90 minutes. Blood samples collected prior to I and after R were analyzed for hydroxyl radical (.OH), nitric oxide (NO), and alanine transferase (ALT). Liver tissues were used to analyze the SOD and catalase mRNA and protein expressions by real-time polymerase chain reaction and Western blot. RESULTS: The results showed that this protocol resulted in elevation of the blood ALT, NO, and .OH levels (P<.001). mRNA (P<.01) and protein expressions (P<.05) of SOD and catalase were all increased. Pretreatment with antioxidant, N-acetyl cysteine, attenuated the liver injury. CONCLUSION: These results indicate that reperfusion of the ischemic liver induced antioxidant enzymes expressions so that oxygen radicals are scavenged. Oxygen radical scavenger could further attenuate the I/R-induced liver injury.     

Protective Effect of Citric Acid Against Hepatic Ischemia Reperfusion Injury in Sprague-Dawley Rats

ObjectiveHepatic ischemia reperfusion (I/R) injury is regarded as a serious concern in clinical practice. Citric acid reduces oxidative stress and inflammation during hypoxia and reoxygenation. Our objective was to investigate the protective effect of citric acid against hepatic I/R injury in rats.MethodsWe fed Sprague-Dawley rats either citric acid (100 mg/kg/d) or saline. One week later, ischemia was induced by clamping the rats’ common hepatic artery and portal vein for 30 minutes. The rats were randomly divided into 3 major groups that were treated as follows: 1. the sham operated group; 2. the I/R group; and 3. the I/R-citric acid group.ResultsCompared to the sham group, the I/R group had higher expression of aspartate aminotransferase and alanine aminotransferase and lower expression of catalase, superoxide dismutase, glutathione peroxidase, antioxidant, nitric oxide, and albumin. Compared to the I/R group, the I/R-citric acid group had higher expression of catalase, superoxide dismutase, antioxidants, and nitric oxide, and lower expression of aspartate aminotransferase and alanine aminotransferase.ConclusionsThese results suggest that citric acid therapy has significant therapeutic potential in ischemic liver injury.     

Rat liver ischemia/reperfusion induced proinflammatory mediator and antioxidant expressions analyzed by gene chips and real-time polymerase chain reactions

OBJECTIVE: Ischemia/reperfusion (I/R) of the rat liver induces injury; however, few studies have investigated gene expressions associated with this phenomenon. In this study, gene chip and real-time polymerase chain reactions (PCR) were used to study the expressions of the proinflammatory mediators and antioxidants after I/R. MATERIALS AND METHODS: Ischemia was induced by clamping the common hepatic artery and portal vein for 40 minutes followed by 90 minutes reperfusion. Blood samples collected before ischemia and after reperfusion were analyzed for alanine amino transferase, lactic dehydrogenase, hydroxyl radicals, nitric oxide (NO), and tumor necrosis factor alpha (TNFalpha). Expressions of TNFalpha, interleukin 12 (IL12), cyclooxygenase II (COXII), and other inflammatory mediators were analyzed by gene chips. COXII, TNFalpha, and antioxidants of mitochondrial superoxide dismutase (SOD(Mn)), catalase, and heat shock protein 70 (HSP70) were double confirmed by real-time PCRs. RESULTS: This protocol resulted in elevations in the blood concentrations of NO, hydroxyl radicals, TNFalpha, ALT, and LDH (P < .01) in the I/R but not the sham-operated group. Reperfusion induced significant increases in the expressions of TNFalpha, IL12, COXII, SOD(Mn), catalase, and HSP70. Real-time PCR also demonstrated increases in mRNA expressions of the proinflammatory mediators and antioxidants. CONCLUSIONS: This protocol resulted in oxidative stress, nitrosative stress, and liver injury. The increases in expressions of both proinflammatory mediators and antioxidants suggested that an imbalance between inflammation and anti-inflammation could be the possible reason for the liver injury after I/R.     

Improved survival in free skin flap transfers in rats

We have demonstrated previously that oxygen-derived free radicals are important mediators of tissue injury in experimental island skin flaps that have been subjected to prolonged ischemia (vascular occlusion) followed by reperfusion. In this study the role of oxygen free radicals in ischemia/reperfusion injury has been investigated in free flap transfers. Groin skin flaps were harvested, stored at room temperature for 21 to 24 hours, and transplanted to the contralateral groin. These free flap transfers normally exhibit a high incidence of complete necrosis. Treatment before the onset of reperfusion with a single dose of superoxide dismutase (SOD), a scavenger of superoxide radicals, increased the survival rate of these skin flaps from 38% in the control group to 76% (p less than 0.025). Tissue levels of SOD were measured before ischemia, after ischemia but before reperfusion, and 30 minutes after reperfusion: untreated flap tissues, which were destined to undergo necrosis, exhibited a significant decrease in SOD activity after reperfusion, whereas SOD-treated flap tissues, destined to survive, demonstrated increased enzyme activity. High levels of tissue SOD activity thus appeared to be associated with improved flap survival. The results have significant clinical implications with regard to organ preservation and transplantation.     

Effects of tetrandrine on ischemia/reperfusion injury in mouse liver

Objective

Hepatic ischemia/reperfusion injury (IRI) may cause acute inflammatory damage, producing significant organ dysfunction, an important problem for liver transplantation. Previous studies have demonstrated that Tetrandrine (Tet), a component of traditional Chinese herbal medicine, shows protective effects to scavenge active oxygen radicals and inhibit lipid peroxidation. In this study, we examined whether Tet has a protective effect on mouse hepatic IRI.

Materials and Methods

Male C57BL/6 mice were divided into sham, ischemic, and Tet-treated groups; 90 minutes of warm ischemia was performed on the left liver lobe. Tet (20 mg/kg) was injected intraperitoneally at 1 hour before ischemia with a second intravenous dose was injected just before reperfusion. Blood and liver samples were collected at 6 hours after reperfusion. We analyzed the hepatocellular injury, oxidative stress, neutrophil recruitment, and tumor necrosis factor-alpha (TNF-α) generation associated with hepatic IRI.

Results

Undergoing 90 minutes of ischemia and 6 hours reperfusion caused dramatic injuries in mouse livers. Administration of Tet (20 mg/kg) reduced serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH); decreased liver edema, TNF-α, myeloperoxidase (MPO) and malondialdehyde (MDA) contents; and ameliorated the down-regulation of superoxide dismutase (SOD) activity.

Conclusion

Tet showed protective effects on mouse hepatic IRI.     

二氮嗪对幼龄大鼠深低温脑缺血再灌注后氧自由基及细胞凋亡的影响

目的 探讨二氮嗪对幼龄大鼠深低温脑缺血再灌注后氧自由基和细胞凋亡的影响及相关的脑保护作用机制.方法 将54只3周龄健康sD大鼠随机分为假手术组、模型组和二氮嗪组,每组18只,建立深低温脑缺血再灌注模型.于术后24 h处死大鼠,检测脑组织超氧化物歧化酶(SOD)、丙二醛的含量,Western Blot法检测脑组织细胞质细胞色素C含量,免疫组化法检测脑组织细胞质Caspase-3含量.结果 模型组脑组织中SOD含量为(198±41)U/mg,低于假手术组的(321±36)U/rag(P<0.01);丙二醛含量为(212±21)nmol/mg,高于假手术组的(100±23)nmol/mg(P<0.01);细胞色素C蛋白表达(0.72±0.09)和Caspase-3蛋白表达(83±10)均高于假手术组(0.17±0.02和115±9)(P<0.01).二氮嗪组脑组织SOD含量为(264±34)U/rag,高于模型组(P<0.05);而丙二醛含量(174±19)nmol/mg、细胞色素C蛋白表达(0.41±0.05)和Caspase-3蛋白表达(99±11)均低于模型组(P<0.05).结论 二氮嗪对幼龄大鼠深低温脑缺血再灌注损伤具有脑保护作用,其机制与抑制氧自由基产生和细胞凋亡有关.     

Effect of Pharmacologic Preconditioning with Tetrandrine on Subsequent Ischemia/Reperfusion Injury in Rat Liver

The effect of tetrandrine (TET) pretreatment of Wistar rats subjected to warm hepatic ischemia/reperfusion (I/R) was investigated. After 50 minutes of ischemia in the left and median lobes of the liver and 24 hours of reperfusion (I/R group), the rats were killed. The TET+I/R group rats were pretreated with TET (50 mg/kg body weight IP) 30 minutes prior to the onset of ischemia. Blood samples were taken for measurement of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH). Tissue was taken from the ischemic lobes for measurement of superoxide dismutase (SOD), malonyldialdehyde (MDA), and myeloperoxidase (MPO); determination of the wet/dry weight (W/D) ratio; and histologic studies. The results showed that ALT, AST, and LDH levels in serum were increased in the I/R group; tissue MDA generation, MPO activity, and the W/D ratio were also increased, accompanied by decreased SOD activity. The serum ALT, AST, and LDH levels, as well as the tissue MPO level and W/D ratio, were lower in the TET+I/R group than in the I/R group; and the SOD level was higher in the TET+IR group than in the I/R group. Moreover, the serum ALT and AST, tissue MDA, and W/D ratio in the TET+I/R group were higher, and the SOD was lower than in the sham group. The histologic examination showed protection against liver damage in the TET+I/R group. The results demonstrated that pretreatment with TET could somewhat protect the liver against I/R injury but does not prevent it. The simultaneous decrease of both lipid peroxide generation and polymorphonuclear neutrophil infiltration in the ischemic liver may explain the acquisition of tolerance following administration of TET.     

联合应用超氧化物歧化酶,阿魏酸钠抗肝缺血再灌注损伤

目的研究联合应用外源性超氧化物歧化酶（ＳＯＤ）与阿魏酸钠（ＳＦ）对肝缺血再灌损伤的保护作用。方法将３２只成年雄性ＳＤ大鼠随机分为对照组、ＳＦ保护组、ＳＯＤ保护组和ＳＦ与ＳＯＤ联合保护组。通过阻断大鼠肝门１ｈ后再开放建立肝缺血再灌注损伤模型,在肝缺血前及肝再灌注２ｈ时测肝组织丙二醛（ＭＤＡ）,ＳＯＤ和测血谷丙转氨酶（ＡＬＴ）,谷草转氨酶（ＡＳＴ）。并取肝组织作光镜及电镜观察。结果再灌注２ｈ时ＳＦ保护组与ＳＯＤ保护组的肝组织ＭＤＡ生成,ＳＯＤ消耗,血清ＡＬＴ,ＡＳＴ升高值均高于ＳＦ与ＳＯＤ联合保护组（Ｐ＜０．０１或Ｐ＜０．０５）,且ＳＦ和ＳＯＤ联合保护组的肝细胞显微、超微结构损害的改变较ＳＯＤ或ＳＦ保护组轻。结论ＳＦ与ＳＯＤ联合保护组清除氧自由基（ＯＦＲ）的作用强于ＳＯＤ或ＳＦ保护组,对鼠肝缺血再灌注所致肝细胞的结构和功能损伤的保护作用比单独使用ＳＯＤ或ＳＦ强。     

Protection of preconditioning, postconditioning and combined therapy against hepatic ishemia/reperfusion injury

Objective： To study the protective effect of ischenlic preconditioning （I-pre） and ischemic postconditioning （I- post） against ischenlia/reperfusion （I/R） injury in rat＇ s liver. Methods： Using rat model of hepatic segmental I/R injury, rats were divided into 5 groups： Group A （sham group）, Group B （I/R injury）, Group C （I-pre group）, Group D （I-post group ） and Group E （combined treatment of I-pre and I-post ）. Serum alanine aminotransferase （ ALT ）, aspartate aminotransferase （ AST）, malondiaidehyde （ MDA ）, glutathione （ GSH ）, superoxide dismutase （ SOD ）, glutathione peroxidase （GSH-Px） and myeloperoxidase （MPO） in hepatic tissues were determined, respectively. In addition, 7 days＇survival of Groups B, C, D and E were evaluated. Results. Compared with Group B, Groups C, D and E exhibited significantly decreased ALT and AST release, minimized tissue injury, suppressed values of MDA and MPO, increased activities of SOD, GSH-Px and GSH （P〈0.05 ）, as well as improved animal survival. The differences among Groups C, D and E were not statistically significant. Conclusions： I-pre, I-post and combined therapy of I-pre and I-post have protective effect against hepatic I/R injury, which is correlated with its function of reducing the production of reactive oxygen species, maintaining the activities of antioxidant systems and suppressing neutrophils recruitment. No additive effect can be obtained in Group E.     

高渗氯化钠羟乙基淀粉40注射液高容量血液稀释对大鼠肝脏缺血再灌注损伤的影响

目的 探讨高渗氯化钠羟乙基淀粉40注射液高容量血液稀释对大鼠肝脏缺血再灌注损伤的影响.方法 雄性Wistar大鼠30只,体重300～350 g,随机分为3组(n=10):假手术组(S组)、缺血再灌注组(IR组)和高容量血液稀释组(HH组).S组仅开腹,不阻断血管;IR组阻断肝门静脉和左肝动脉30 min,再灌注2 h;HH组30 min内经尾静脉输注高渗氯化钠羟乙基淀粉40注射液10 ml/kg进行高容量血液稀释,输注完毕后15 min,行肝脏缺血再灌注.再灌注2 h时,下腔静脉取血样,测定血清谷丙转氨酶(ALT)和谷草转氨酶(AST)的活性;取左肝叶组织,光镜下观察病理学结果,采用比色法测定丙二醛(MDA)含量,采用黄嘌呤氧化酶法测定超氧化物歧化酶(SOD)活性.结果 与S组比较,IR组和HH组血清ALT和AST的活性、肝组织MDA含量升高,肝组织SOD活性降低(P<0.01),肝组织病理学损伤明显;与IR组比较,HH组血清ALT和AST的活性、肝组织MDA含量降低,肝组织SOD活性升高(P<0.01),肝组织病理学损伤减轻.结论 高渗氯化钠羟乙基淀粉40注射液高容量血液稀释可减轻大鼠肝脏缺血再灌注损伤,可能与氧自由基生成减少有关.     

l-Arginine Supplementation Protects Against Hepatic Ischemia-Reperfusion Lesions in Rabbits

We evaluated the effects of a substrate in the biosynthesis of nitric oxide (NO)-l-arginine (LARG)-on hepatic lesions caused by ischemia/reperfusion (I/R) injury in rabbit livers. Rabbits were pretreated with LARG (150 mg/kg IV) or saline solution 0.9% (SS) before the hepatic I/R procedure. The effects of LARG on hepatic injury were evaluated before and after I/R. The warm hepatic I/R procedure produced profound acute liver injury, as indicated by elevated values of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactic dehydrogenase (LDH), as well as a high apoptotic cell count. All changes were attenuated by treatment with LARG before the hepatic I/R procedure. These results suggested that LARG produced protective effects on hepatic I/R lesions. This protective effect of LARG was probably associated with blocking generation of superoxide anions during the hepatic I/R procedure.     

Ambroxol Alleviates Hepatic Ischemia Reperfusion Injury by Antioxidant and Antiapoptotic Pathways

Background

Hepatic ischemia/reperfusion (HI/R) injury is a common pathologic process caused by many clinical settings, such as liver resection, liver transplantation, hypovolemic shock, and trauma. The use of ambroxol, which acts as a mucolytic agent, provides antioxidant and anti-inflammatory effects.

Methods

A rat model of HI/R was induced by clamping the hepatic artery, the hepatoportal vein, and the bile duct with a vascular clamp for 30 minutes followed by reperfusion for 6 hours under anesthesia. The sham group underwent laparotomy without hepatic ischemia. The ambroxol group was injected into the tail vein in the ambroxol group 5 minutes before HI/R at one dose of 20 mg/kg, 80 mg/kg, or 140 mg/kg. The control group underwent the same procedure as the ambroxol group but with administration of physiological saline. Liver injury was evaluated by biochemical and histopathological examinations. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were assayed in serum samples. Superoxide dismutase (SOD), catalase (CAT), malondiadehyde (MDA), and glutathione (GSH) were spectrophotometrically measured. Furthermore, caspase-3, Bcl-2 and Bax expression as well as the level of c-Jun N-terminal kinases (JNK) we estimated activation.

Results

Wistar rats that received 20, 80 mg or 140 mg of ambroxol displayed reduced HI/R injury compared with controls. Use of ambroxol reduced the histologic injury and significantly decreased serum ALT and AST levels. In addition, ambroxol enhanced the activity of hepatic tissue SOD and CAT, increasing GSH but decreasing MDA tissue contents. In the ambroxol group, Bcl-2 expression was increased and Bax and caspase-3 decreased compared with the controls. Furthermore, ambroxol reduced levels of phosphorylated JNK (P < .05).

Conclusion

These results indicated that ambroxol attenuated rat HI/R through upregulation of intracellular antioxidant and anti-apoptotic signaling pathways.