8-OHdG在不同级别胶质瘤中的表达及意义

目的：探讨8-羟基脱氧鸟苷（8-OHdG）在不同级别胶质瘤中的表达及其意义。方法：采用免疫组化SP法检测45例不同级别胶质瘤组织中8-OHdG的表达,并结合临床资料分析其与胶质瘤临床特征之间的关系。结果：DNA氧化性损伤标志物8-OHdG在高级别（Ⅲ-Ⅳ级）胶质瘤中的表达强于低级别（Ⅰ-Ⅱ级）胶质瘤,在不同性别、年龄的胶质瘤患者中8-OHdG的表达差异无统计学意义。结论：高级别胶质瘤组织中的DNA氧化性损伤较低级别严重,8-OHdG可作为胶质瘤病理级别的辅助性诊断指标。

Effect of Chromium on Oxidative Damage and Antioxidant Capacity of Ctenopharyngodon idellus

[Objective] This study aimed to investigate the effect of chromium on ox- idative damage and antioxidant capacity of Ctenopharyngodon idellus （grass carp）. [Method] The grass carps were treated with hexavalent chromium （Cr^6＋） solution at concentrations of 0, 7.23, 14.47, 28.94 mg/L, and then the content of malondialde- hyde （MDA）, the level of total antioxidative capacity （T-AOC） and the activity of gtu- tathione-S-transferase （GST） in the hepatopancreas of grass carp were determined after 96 hours in different treatment groups. [Result] The content of MDA presented increasing trend with the increase of exposure Cr^6＋ concentrations. The activity of T-AOC increased firstly, then decreased with the increasing Cr^6＋ exposure concentra- tions, showing that the level of T-AOC was induced in tow and medium concentrat ions （7.23 and 14.47 mg/L）, but inhibited in high concentrations （28.94 mg/L）. Among the exposure groups, the level of T-AOC in medium concentration group （14.47 mg/L） was significantly higher than the control （P〈0.05）. Except the low concentration groups （7.23 mg/L） of which the GST activity was slightly induced, the GST activities of the other groups all showed downward trend with increasing Cr^6＋ levels, and the activity of GST in 28.94 mg/L group was significantly lower than the control group （P〈0.05）. [Conclusion] Cr^6＋ could cause large oxidative damage in the hepatopancreas of grass carp, thus poisoning it, and Cr^6＋ may further damage the organizational structure and physiological function of grass carp.

Protective Effects of Zingiberis and Acniti Praeparatae Decoction on Myocardial IschemiaReperfusion Injury in Rats

This study aimed to investigate the protective effects of zin-giberis and acniti praeparatae decoction on oxidative stress injury induced by my-ocardial ischemia reperfusion in rats. [Method] Myocardial ischemia-reperfusion was performed by ligation of the left anterior descending coronary artery for 30 min, fol-lowed by reperfusion for 60 min. The effects of zingiberis and acniti praeparatae decoction on ECG ST segment, myocardial infarction percentage, malondialdehyde （MDA） content in the serum, superoxide dismutase （SOD） activity and other indica-tors were observed. [Result] Zingiberis and acniti praeparatae decoction could effec-tively inhibit ECG ST segment elevation caused by myocardial ischemia-reperfusion injuries, reduce the percentage of myocardial infarction, decline the content of MDA in the serum, and increase the activity of SOD. [Conclusion] Zingiberis and acniti praeparatae decoction exhibits protective effects on oxidative injuries caused by my-ocardial ischemia-reperfusion injuries in rats, which may be involved in reducing the formation of myocardial free radicals and enhancing antioxidant capacity of my-ocardium.

Protective effect of estradiol on hepatocytic oxidative damage

AIM: To examine the protective effect of estradiol on the cultured hepatocytes under oxidative stress. METHODS: Hepatocytes of rat were isolated by using perfusion method, and oxidative stress was induced by a serum-free medium and FeNTA. MDA level was determined with TBA method. Cell damage was assessed by LDH assay. Apoptosis of hepatocytes was assessed with cytoflowmetric analysis. Expression of Bcl-xl in cultured hepatocytes was detected by Western blot. The radical-scavenging activity of estradiol was valued by its ability to scavenge the stable free radical of DDPH. RESULTS: Oxidative stress increased LDH from 168 +/- 25 x 10(-6)IU.cell(-1) to 780 +/- 62 x 10(-6)IU.cell(-1) and MDA(from 0.28 +/- 0.07 x 10(-6)nmol.cell(-1) to 1.35 +/- 0.12 x 10(-6)nmol.cell(-1)) levels in cultured hepatocyte, and estradiol inhibited both LDH and MDA production in a dose dependent manner. In the presence of estradiol 10(-6)mol.L(-1), 10( -7 )mol.L(-1) and 10(-8)mol.L(-1),the LDH levels are 410 +/- 53 x 10(-6)IU.cell(-1) (P【0.01 vs oxidative group), 530 +/- 37 X 10(-6)IU.cell(-1 ) (P【0.01 vs oxidative group), 687+/-42 x 10(-6)IU.cell(-1) (P【0.05 vs oxidative group) respectively, and the MDA level are 0.71+/-0.12 x 10(-6)nmol.cell(-1) (P【0.01 vs oxidative group),0.97+/-0.11 x 10(-6)nmol.cell(-1 )(P【0.01 vs oxidative group) and 1.27+/-0.19 x 10(-6)nmol.cell(-1) respectively. Estradiol suppressed apoptosis of hepatocytes induced by oxidative stress, administration of estradiol(10(-6)mol/L)decreased the apoptotic rate of hepatocytes under oxidative stress from 18.6 +/- 1.2% to 6.5 +/-2.5%, P【0.01. Bcl-xl expression was related to the degree of liver cell damage due to oxidative stress, and estradiol showed a protective action. CONCLUSION: Estradiol protects hepatocytes from oxidative damage by means of its antioxidant activity.

Bile-acid-induced cell injury and protection

Several studies have characterized the cellular and molecular mechanisms of hepatocyte injury caused by the retention of hydrophobic bile acids （BAs） in cholestatic diseases. BAs may disrupt cell membranes through their detergent action on lipid components and can promote the generation of reactive oxygen species that, in turn, oxidatively modify lipids, proteins, and nucleic acids, and eventually cause hepatocyte necrosis and apoptosis. Several pathways are involved in triggering hepatocyte apoptosis. Toxic BAs can activate hepatocyte death receptors directly and induce oxidative damage, thereby causing mitochondrial dysfunction, and induce endoplasmic reticulum stress. When these compounds are taken up and accumulate inside biliary cells, they can also cause apoptosis. Regarding extrahepatic tissues, the accumulation of BAs in the systemic circulation may contribute to endothelial injury in the kidney and lungs. In gastrointestinal cells, BAs may behave as cancer promoters through an indirect mechanism involving oxidative stress and DNA damage, as well as acting as selection agents for apoptosis-resistant cells. The accumulation of BAs may have also deleterious effects on placental and fetal cells. However, other BAs, such as ursodeoxycholic acid, have been shown to modulate BA-induced injury in hepatocytes. The major beneficial effects of treatment with ursodeoxycholic acid are protection against cytotoxicity due to more toxic BAs; the stimulation of hepatobiliary secretion; antioxidant activity, due in part to an enhancement in glutathione levels; and the inhibition of liver cell apoptosis. Other natural BAs or their derivatives, such as cholyI-N- methylglycine or pharmacological properties. cholylsarcosine, interest owing have also aroused to their protective

Glutamine is highly effective in preventing in vivo cobalt-induced oxidative stress in rat liver

AIM: To evaluate the in vivo effect of glutamine on cobaltgenerated oxidative stress and (HO-1) induction in rat liver.METHODS: Fasted female Wistar rats received a single injection of cobalt chloride (375 μmol/kg body weight) and then were killed at different times. Lipid peroxidation and soluble and enzymatic antioxidant defense system (reduced glutathione (GSH), catalase (CAT), glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD)) were measured in liver homogenates. Ferritin and ferritin iron contents as well as heme oxygenase-1 (HO-1) activity and expression were also determined. The antioxidant properties of glutamine (Gin) were also evaluated. RESULTS: Cobalt chloride increased lipid peroxidation (50% over control values) 1 h after treatment. GSH reached a minimum at 3 h (40%) increasing thereafter. Twelve hours after CoCl2 injection, the antioxidant enzymes CAT, GSH-Px and SOD also diminished by about 30%. Heme oxygenase-1 induction was observed 6 h after treatment reaching a maximum value of 14-fold over the controls, 12 h after cobalt treatment. A 1.7-fold increase in ferritin and ferritin-bound iron 24 h after treatment were also obtained. Administration of glutamine (300 mg/kg body weight) by gavage 24 h before CoCl2 treatment entirely prevented the increase in thiobarbituric acid reactive substances (TBARS) content, the decrease in GSH levels, and partially reverted heme oxygenase-1 induction. CONCLUSION: These results suggested that a natural product such as glutamine prevents glutathione depletion and consequently heme oxygenase induction.

Ameliorative effects of bombesin and neurotensin on trinitrobenzene sulphonic acid-induced colitis,oxidative damage and apoptosis in rats

AIM:To investigate the effects of bombesin (BBS) and neurotensin (NTS) on apoptosis and colitis in an ulcerative colitis model. METHODS:In this study, a total of 50 rats were divided equally into 5 groups. In the control group, no colitis induction or drug administration was performed. Colitis was induced in all other groups. Following the induction of colitis, BBS, NTS or both were applied to three groups of rats. The remaining group (colitis group) received no treatment. On the 11th d after induction of colitis and drug treatment, blood samples were collected for TNF-α and IL-6 level studies. Malondialdehyde (MDA), carbonyl, myeloperoxidase (MPO) and caspase-3 activities, as well as histopathological findings, evaluated in colonic tissues. RESULTS:According to the macroscopic and microscopic findings, the study groups treated with BBS, NTS and BBS + NTS showed significantly lower damage and inflammation compared with the colitis group (macroscopic score, 2.1 ± 0.87, 3.7 ± 0.94 and 2.1 ± 0.87 vs 7.3 ± 0.94;microscopic score, 2.0 ± 0.66, 3.3 ± 0.82 and 1.8 ± 0.63 vs 5.2 ± 0.78, P < 0.01). TNF-α and IL-6 levels were increased significantly in all groups compared with the control group. These increases were significantly smaller in the BBS, NTS and BBS + NTS groups compared with the colitis group (TNF-α levels, 169.69 ± 53.56, 245.86 ± 64.85 and 175.54 ± 42.19 vs 556.44 ± 49.82;IL-6 levels, 443.30 ± 53.99, 612.80 ± 70.39 and 396.80 ± 78.43 vs 1505.90 ± 222.23, P < 0.05). The colonic MPO and MDA levels were significantly lower in control, BBS, NTS and BBS + NTS groups than in the colitis group (MPO levels, 24.36 ± 8.10, 40.51 ± 8.67 and 25.83 ± 6.43 vs 161.47 ± 38.24;MDA levels, 4.70 ± 1.41, 6.55 ± 1.12 and 4.51 ± 0.54 vs 15.60 ± 1.88, P < 0.05). Carbonyl content and caspase-3 levels were higher in the colitis and NTS groups than in control, BBS and BBS + NTS groups (carbonyl levels, 553.99 ± 59.58 and 336.26 ± 35.72 vs 209.76 ± 30.92, 219.76 ± 25.77 and 220.34 ± 36.95;caspase-3 levels, 451.70 ± 68.27 and 216.20 ± 28.17 vs 28.60 ± 6.46, 170.50 ± 32.37 and 166.50 ± 30.95, P < 0.05). CONCLUSION:The results of this study suggest BBS and NTS, through their anti-inflammatory actions, support the maintenance of colonic integrity and merit consideration as potential agents for ameliorating colonic inflammation.

N-acetylcysteine attenuates alcohol-induced oxidative stress in the rat

AIM: There is increasing evidence that alcohol-induced liverdamage may be associated with increased oxidative stress.We aimed to investigate free-radical scavenger effect of n-acetylcysteine in rats intragastrically fed with ethanol.METHODS: Twenty-four rats divided into three groups werefed with ethanol (6 g/kg/day, Group 1), ethanol and n-acetylcysteine (1 g/kg, Group 2), or isocaloric dextrose(control group, Group 3) for 4 weeks. Then animals weresacrificed under ether anesthesia, intracardiac blood andliver tissues were obtained. Measurements were performedboth in serum and in homogenized liver tissues.Malondialdehyde (MDA) level was measured by TBARSmethod. Glutathione peroxidase (GSH-Px) and superoxidedismutase (SOD) levels were studied by commercial kits.Kruskal-Wallis test was used for statistical analysis.RESULTS: ALT and AST in Group 1 (154 U/Land 302 U/L,respectively) were higher than those in Group 2 (94 U/L and155 U/L) and Group 3 (99 U/L and 168 U/L) (P＝0.001 forboth). Serum and tissue levels of MDA in Group 1 (1.84 nmol/mL and 96 nmol/100 mg-protein) were higher than Group 2(0.91 nmol/mL and 64 nmol/100 mg-protein) and Group 3(0.94 nmol/mL and 49 nmol/100 mg-protein) (P＜0.001 forboth). On the other hand, serum GSH-Px level in Group 1(8.21 U/g-Hb) was lower than Group 2 (16 U/g-Hb) andGroup 3 (16 U/g-Hb) (P＜0.001). Serum and liver tissue levelsof SOD in Group 1 (11 U/mL and 26 U/100 mg-protein)were lower than Group 2 (18 U/mL and 60 U/100 mg-protein)and Group 3 (20 U/mL and 60 U/100 mg-protein) (P＜0.001for both).CONCLUSION: This study demonstrated that ethanol-induced liver damage is associated with oxidative stress,and co-administration of n-acetylcysteine attenuates thisdamage effectively in rat model.

N-acetylcysteine attenuates alcohol-induced oxidative stess in rats

AIM:To investigate free-radical scavenger effect of n- acetylcysteine in rats intragastrically fed with ethanol. METHODS:Twenty-four rats divided into three groups were fed with ethanol (6 g/kg/day,Group 1),ethanol and n- acetylcysteine (1 g/kg,Group 2),or isocaloric dextrose (control group,Group 3) for 4 weeks.Then animals were sacrificed under ether anesthesia,and intracardiac blood and liver tissues were obtained.Measurements were made in both serum and homogenized liver tissues. Malondialdehyde (MDA) level was measured by TBARS method.Glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) levels were studied by commercial kits. Kruskal-Wallis test was used for statistical analysis. RESULTS:ALT and AST in Group 1 (154 U/L and 302 U/L, respectively) were higher than those in Group 2 (94 U/L and 155 U/L) and Group 3 (99 U/L and 168 U/L) (P=0.001 for both).Serum and tissue levels of MDA in Group 1 (1.84 nmol/mL and 96 nmol/100 mg-protein) were higher than that in Group 2 (0.91 nmol/mL and 64 nmol/100 mg protein) and Group 3 (0.94 nmol/ml and 49 nmol/100 mg-protein) (P<0.001 for both).On the other hand,serum GSH-Px level in Group 1 (8.21 U/g Hb) was lower than that in Group 2 (16 U/g Hb) and Group 3 (16 U/g-Hb) (P<0.001).Serum and liver tissue levels of SOD in Group 1 (11 U/mL and 26 U/100 rag-protein) were lower than that in Group 2 (18 U/ mL and 60 U/100 mg protein) and Group 3 (20 U/mL and 60 U/100 rag-protein) (P<0.001 for both). CONCLUSION:Ethanol-induced liver damage was associated with oxidative stress,and co-administration of n-acetylolsteine attenuates this damage effectively in rat model.

CYP2E1-dependent hepatotoxicity and oxidative damage after ethanol administration in human primary hepatocytes

AIM： To observe the relationship between ethanol-induced oxidative damage in human primary cultured hepatocytes and cytochrome P450 2E1 （CYP2E1） activity, in order to address if inhibition of CYP2E1 could attenuate ethanol- induced cellular damage. METHODS： The dose-dependent （25-100 mmol/L） and time-dependent （0-24 h） exposures of primary human cultured hepatocytes to ethanol were carried out. CYP2E1 activity and protein expression were detected by spectrophotometer and Western blot analysis respectively. Hepatotoxicity was investigated by determination of lactate dehydrogenase （LDH） and aspartate transaminase （AST） level in hepatocyte culture supernatants, as well as the intracellular formation of malondialdehyde （MDA）. RESULTS： A dose-and time-dependent response between ethanol exposure and CYP2E1 activity in human hepatocytes was demonstrated. Moreover, there was a time-dependent increase of CYP2E1 protein after 100 mmol/L ethanol exposure. Meanwhile, ethanol exposure of hepatocytes caused a time-dependent increase of cellular MDA level, LDH, and AST activities in supernatants. Furthermore, the inhibitor of CYP2E1, diallyl sulfide （DAS） could partly attenuate the increases of MDA, LDH, and AST in human hepatocytes. CONCLUSION： A positive relationship between ethanolinduced oxidative damage in human primary cultured hepatocytes and CYP2E1 activity was exhibited, and the inhibition of CYP2E1 could partly attenuate ethanol-induced oxidative damage.

Lansoprazole prevents experimental gastric injury induced by non-steroidal anti-inflammatory drugs through a reduction of mucosal oxidative damage

AIM:This study investigated the mechanisms of protection afforded by the proton pump inhibitor lansoprazole against gastric injury induced by different non-steroidal anti-inflammatory drugs (NSAIDs) in rats. METHODS: Male Sprague-Dawley rats were orally treated with indomethacin (100 μmol/kg), diclofenac (60 μmol/kg), piroxicam (150 μmol/kg) or ketoprofen (150 μmol/kg). Thirty minutes before NSAIDs, animals were orally treated with lansoprazole 18 or 90 umol/kg. Four hours after the end of treatments, the following parameters were assessed: gastric mucosal PGE2, malondialdehyde (MDA), myeloperoxidase (MPO) or non-proteic sulfhydryl compounds (GSH) levels; reverse transcription-polymerase chain reaction (RT-PCR) of mucosal COX-2 mRNA; gastric acid secretion in pylorus-ligated animals; in vitro effects of lansoprazole (1-300 μmol/L) on the oxidation of low density lipoproteins (LDLs) induced by copper sulphate. RESULTS: All NSAIDs elicited mucosal necrotic lesions which were associated with neutrophil infiltration and reduction of PGE2 levels. Increments of MPO and MDA contents, as well as a decrease in GSH levels were detected in the gastric mucosa of indomethacin- or piroxicam-treated animals. Indomethacin enhanced mucosal cyclooxygenase-2 expression, while not affecting cyclooxygenase-1. At the oral dose of 18 μmol/kg lansoprazole partly counteracted diclofenac-induced mucosal damage, whereas at 90 μmol/kg it markedly prevented injuries evoked by all test NSAIDs. Lansoprazole at 90 μmol/kg reversed also the effects of NSAIDs on MPO, MDA and GSH mucosal contents, without interfering with the decrease in PGE2 levels or indomethacin-induced cyclooxygenase-2 expression. However, both lansoprazole doses markedly inhibited acid secretion in pylorus-ligated rats. Lansoprazole concentration-dependently reduced the oxidation of LDLs in vitro. CONCLUSION: These results suggest that, besides the inhibition of acid secretion, lansoprazole protection against NSAID-induced gastric damage depends on a reduction in mucosal oxidative injury, which is also responsible for an increment of sulfhydryl radical bioavailability. It is also suggested that lansoprazole does not influence the down-regulation of gastric prostaglandin production associated with NSAID treatment.

Reduced antioxidant level and increased oxidative damage in intact liver lobes during ischaemia-reperfusion

AIM： To determine whether increased blood flow of the liver can cause oxidative stress and hepatocyte damage, and to elaborate methods suitable for measuring the antioxidant defence during hepatic surgery on rat model.METHODS： In nembutal narcosis, the left lateral and the medial lobes of the liver were clipped for 45 rain to make the total blood supply flow through the other lobes. Total antioxidant status, glutathione peroxidase and superoxide dysmutase activity, as well as the concentrations of diene conjugates and free sulphydril groups, H-donating ability and reducing power of the liver samples were determined. Chemiluminescent intensity of the liver was also measured. Metal ions （Al, Ca, Cu, Fe, Mg, Mn, Zn） and P and S concentrations of the liver were determined with an inductively coupled plasma optical emission spectrometer and Se content was measured by cathodic stripping voltammetry.RESULTS： Glutathione peroxidase and superoxide dysmutase activities of the liver decreased significantly in the hyperemia group compared to those observed in the sham operated group. The level of total antioxidant status was also significantly lower in the hyperemia group. H-donating ability, reducing power and free sulphydril group concentration showed the same tendency. A significant correlation （P〈0.05） was found between the changes in non-specific antioxidant activities. This pointed to simultaneous activity of the antioxidant defence system. Al, Cu, Mn, Zn, and S were lower in the hyperemia group than in the sham operated group when the levels of Ca, Fe, Mg, Se and P ions were higher during hyperemia.CONCLUSION： Oxidative stress is one of the main factors for the injury of intact liver lobes during ischaemia-reperfusion.

Experimental and clinical evidence of antioxidant therapy in acute pancreatitis

Oxidative stress has been shown to play an important role in the pathogenesis of acute pancreatitis (AP). Antioxidants, alone or in combination with conventional therapy, should improve oxidative-stress-induced organ damage and therefore accelerate the rate of recovery. In recent years, substantial amounts of data about the efficiency of antioxidants against oxidative damage have been obtained from experiments with rodents. Some of these antioxidants have been found beneficial in the treatment of AP in humans; however, at present there is insufficient clinical data to support the benefits of antioxidants, alone or in combination with conven-tional therapy, in the management of AP in humans. Conflicting results obtained from experimental animals and humans may represent distinct pathophysiological mechanisms mediating tissue injury in different species. Further detailed studies should be done to clarify the exact mechanisms of tissue injury in human AP. Herein I tried to review the existing experimental and clinical studies on AP in order to determine the efficiency of antioxidants. The use of antioxidant enriched nutrition is a potential direction of clinical research in AP given the lack of clues about the efficiency and safety of antioxidant usage in patients with AP.

Oxidative damage,pro-inflammatory cytokines,TGF-αand c-myc in chronic HCV-related hepatitis and cirrhosis

AIM： To assess whether a correlation exists between oxidative DNA damage occurring in chronic HCV-related hepatitis and expression levels of pro-inflammatory cytokines, TGF-α and c-myc. METHODS： The series included 37 patients with chronic active HCV-related hepatitis and 11 with HCV-related compensated cirrhosis. Eight-hydroxydeoxyguanosine in liver biopsies was quantified using an electrochemical detector. The mRNA expression of TNF-α, IL-1β, TGF-α and c-myc in liver specimens was detected by semiquantitative comparaUve RT-PCR. RESULTS： TNF-α levels were significantly higher in hepatitis patients than in cirrhosis patients （P=0.05）. IL-1β was higher in cirrhosis patients （P=0.05）. A sig- nificant correlation was found between TNF-α and staging （P= 0.05） and between IL-1β levels and grading （P=0.04）. c-myc showed a significantly higher expression in cirrhosis patients （P=0.001）. Eight-hydroxydeoxyguanosine levels were significantly higher in cirrhosis patients （P=0.05） and in HCV genotype 1 （P=0.03）. Considering all patients, 8-hydroxydeoxyguanosine levels were found to be correlated with genotype （P=0.04） and grading （P=0.007）. Also multiple logistic regression analysis demonstrated a significant correlation among the number of DNA adducts, TNF-α expression and HCV genotype （P= 0.02）. CONCLUSION： In chronic HCV-related liver damage, oxidative DNA damage correlates with HCV genotype, grading and TNF-α levels. As HCV-related liver damage progresses, TNF-α levels drop while IL-1β and c-myc levels increase, which may be relevant to liver carcinogenesis.

Decreased mitochondrial deoxyribonucleic acid and increased oxidative damage in chronic hepatitis C

AIM： To determine whether alteration of the mito- chondria DNA （mtDNA） copy number and its oxidative damage index （mtDNA△CT） can be detected by analysis of peripheral blood cells in hepatitis C virus （HCV）- infected patients. METHODS： This study enrolled two groups of pa- tients aged 40-60 years： a control group and an HCV- infected group in Department of Gastroenterology and Hepatology in Changhua Christian Hospital. Patients with co-infection with hepatitis B virus or human im- munodeficiency virus, autoimmune disease, malignant neoplasia, pregnancy, thyroid disease, or alcohol con- sumption 〉 40 g/d were excluded. HCV-infected pa- tients who met the following criteria were included： （1） positive HCV antibodies for 〉 6 mo; （2） alanine aminotransferase （ALT） levels more than twice the upper lim- it of normal on at least two occasions during the past 6 mo; and （3） histological fibrosis stage higher than F1. The mtDNA copy number and oxidative damage index of HCV mtDNA （mtDNA△CT） were measured in periph- eral blood leukocytes. The association between mtDNA copy number and mtDNA△CT was further analyzed using clinical data. RESULTS： Forty-seven normal controls （male/female： 26/21, mean age 50.51 ± 6.15 years） and 132 HCV- infected patients （male/female： 76/61, mean age 51.65 ± 5.50 years） were included in the study. The geno- types of HCV-infected patients include type 1a （n = 3）, type 1b （n = 83）, type 2a （n = 32）, and type 2b （n = 14）. Liver fibrosis stages were distributed as follows： F1/F2/F3/F4 = 1/61/45/25 and activity scores were A0/ A1/A2/A3 = 7/45/55/25. There were no age or gender differences between the two groups. HCV-infected pa- tients had higher hepatitis activity （aspartate transami- nase levels 108.77 ± 60.73 vs 23.19 ± 5.47, P 〈 0.01; ALT levels 168.69 ± 93.12 vs 23.15 ± 9.45, P 〈 0.01） and lower platelet count （170.40±58.00 vs 251.24 ± 63.42, P 〈 0.01） than controls. The mtDNA copy num- ber was lower in HCV-infected patients than in controls （173.49 vs 247.93, P 〈 0.05）. The mtDNA△CT was higher in HCV-infected patients than in controls （2.92 vs 0.64, P 〈 0.05）. To clarify the clinical significance of these results in HCV-infected patients, their association with different clinical parameters among HCV-infected pa- tients was analyzed. A negative association was found between mtDNA copy number and elevated aspartate transaminase levels （r = -0.17, P 〈 0.05）. Changes in mtDNA copy number were not associated with HCV RNA levels, HCV genotypes, liver fibrosis severity, or inflammatory activity in the liver biopsy specimen. How- ever, a correlation was observed between mtDNA△CT and platelet count （r = -0.22, P 〈 0.01）, HCV RNA level （r = 0.36, P 〈 0.01）, and hepatitis activity （r = 0.20, P = 0.02）. However, no difference in the change in mtDNA△CT was observed between different fibrosis stages or HCV CONCLUSION： Oxidative stress and mtDNA dam- age are detectable in patient＇s peripheral leukocytes. Increased leukocyte mtDNA△CT correlates with higher HCV viremia, increased hepatitis activity, and lower platelet count.

Polaprezinc protects human colon cells from oxidative injury induced by hydrogen peroxide:Relevant to cytoprotective heat shock proteins

AIM： To investigate the effect of polaprezinc on cellular damage induced by hydrogen peroxide （H202） in human colon CaCo2 cells. METHODS： CaCo2 cells were treated with polaprezinc （10-100 pmol/L） for 6 h. After polaprezinc treatment, the cells were incubated with H202 （20μmol/L） for 1 h. Cell viability was measured by MTT assay. Western blot analysis for heat shock protein （HSP） 27 and HSP72 in the cells was performed. Moreover, cells were pretreated with quercetin （200 μmol/L）, an inhibitor of HSP synthesis, 2 h before polaprezinc treatment, and cell viability and the expression of HSP27 and 72 were assessed in these cells. RESULTS： Polaprezinc significantly protected CaCo2 cells from cell damage induced by H2O2, and up-regulated the expressions of HSP27 and HSP72 in the cells （10, 30 and 100 pmol/L of polaprezinc; 35.0% ± 7.7%, 58.3% ± 14.6% and 64.2% ± 8.2%, respectively. P 〈 0.01 versus polaprezinc-nontreated cells; 6.0% ± 4.4%）. Quercetin inhibited the up-regulation of HSP27 and HSP72 by polaprezinc and diminished the protective effect of polaprezinc against H2O2-caused injury in the cells. CONCLUSION： Polaprezinc is a useful therapeutic agent for treatment of colitis and its effects depend on the function of cytoprotective HSP in colon.

Protective effect of ascorbic acid in experimental gastric cancer: reduction of oxidative stress

AIM;Oxidative stress participates in the cell carcinogenesis by inducing DNA mutations.Our aim was to assess whether ascorbic acid,an antioxidant,could have a role in preventing ROS(Reactive Oxygen Species)generation in experimental gastric carcinoma in a rat model. METHODS:Experimental gastric cancer was induced in twelve Wistar male rats(weighting 250-350 g)by profound duodeno-gastric reflux throught split gastrojenunostomy.The rats were allocated to the following groups:Group Ⅰ(n=6) was the control;Group Ⅱ(n=6)which was mantained with daily intake of tape water with Vitamin C(30 mg/Kg).After 6 or 12 months,samples of gastric tumor or non tumor mucosa were taken from the anastomosis of both groups. Oxidative stress was measured by superoxide quantification through lucigenin-amplified chemiluminescence base and by staining with Nitrobluetetrazolium.The histopathologic confirmation of adenocarcinoma was made by eosin- hemathoxilin method. RESULTS:The intestinal type of gastric adenocarcinoma was microscopically identified in all animals of group Ⅰ whereas only 3 rats of group Ⅱ showed an adenocarcinoma without macroscopic evidence of them.The cancers were located in the anastomosis in all cases.Basal luminescence from tumor gastric tissue generated 38.4±6.8 count per minute/mg/×10~6(mean±SD)and 14.9±4.0 count per minute/mg/×10~6,respectively,in group Ⅰ and Ⅱ animals(P <0.05).The Nitrobluetetrazolium method showed intense staining in tumor tissues but not in non neoplasic mucosa. CONCLUSION:Experimental gastric tumors seem to produce more reactive oxygen species than non neoplasic gastric tissue.The reduction of oxidative stress and gastric tumor incidence in rats were induced by the intake of ascorbic acid.Therefore,it may have a role in the prevention of gastric carcinoma. Oliveira CPMS Kassab P Lopasso FP Souza HP Janiszewski M Laurindo FRM Iriya K Laudanna AA.Protective effect of ascorbic acid in experimental gastric cancer:reduction of oxidative stress.World J Gastroenterol 2003;9(3):446-448 http://www.wjgnet.com/1007-9327/9/446.htm

PROTECTION OF CARBON MONOXIDE INHALATION ON LIPOPOLY-SACCHARIDE-INDUCED MULTIPLE ORGAN INJURY IN RATS

Objective To observe the protection of carbon monoxide （CO） inhalation on lipopolysaccharide （LPS）-induced rat multiple organ injury. Methods Sprague-Dawley rats with multiple organ injury induced by 5 mg/kg LPS intravenous injection were exposed to room air or 2.5 × 10 ^-4 （V/V） CO for 3 hours. The lung and intestine tissues of rats were harvested to measure the expression of heme oxygenase-1 （ HO-1 ） with reverse transcription-polymerase chain reaction, the levels of pulmonary tumor necrosis factor-or （ TNF-α）, interleukin-6 （ IL-6）, and intestinal platelet activator factor （ PAF）, intercellular adhesion molecule-1 （ICAM-1） with enzyme-linked immunosorbent assay, the content of maleic dialdehyde （MDA） and the activity of myeloperoxidase （MPO） with chemical method, the cell apoptosis rate with flow cytometry, and the pathological changes with light microscope. Results CO inhalation obviously up-regulated the expression of HO-1 in lung （5.43 ± 0. 92） and intestine （6. 29 ± 1.56） in LPS ＋ CO group compared with （ 3.08 ± 0. 82） and （ 3.97 ± 1.16 ） in LPS group （ both P 〈 0. 05 ）. The levels of TNF-ot, IL-6 in lung and PAF, ICAM-1 in intestine ofLPS ＋ CO group were 0. 91 ±0. 25,0. 64 ±0.05, 1. 19 ± 0. 52, and 1.83 ±0. 35 pg/mg, respectively, significantly lower than the corresponding values in LPS group （ 1.48 ± 0. 23, 1.16 ± 0. 26, 1.84 ± 0. 73, and 3.48 ± 0. 36 pg/mg, all P 〈 0. 05 ）. The levels of MDA, MPO, and cell apoptosis rate in lung and intestine of LPS ＋ CO group were 1.02 ± 0. 23 nmol/mg, 1.74 ± 0. 17 nmol/mg, 7.18 ± 1.62 U/mg, 6. 30 ±0. 97 U/mg, 1.60% ±0. 34%, and 30. 56% ±6. 33%, respectively, significantly lower than the corresponding values in LPS group （ 1.27 ± 0. 33 nmol/mg, 2. 75 ± 0. 39 nmol/mg, 8. 16 ± 1.49 U/mg, 7. 72 ± 1.07 U/mg, 3.18% ±0. 51%, and 41.52% -＋3.36%, all P 〈0.05）. In addition, injury of lung and intestine induced by LPS was attenuated at presence of CO inhalation. Conclusion CO inhalation protects rat lung and intestine from LPS-induced injury via anti-oxidantion, anti-inflammation, anti-apoptosis, and up-regulation of HO-1 expression.

Hepatic injury induced by carbon dioxide pneumoperitoneum in experimental rats

AIM： To observe the hepatic injury induced by carbon dioxide pneumoperitoneum in rats and to explore its potential mechanism.METHODS： Thirty healthy male SD rats were randomly divided into control group （n = 10）, 0 h experimental group （n = 10） and 1 h experimental group （n = 10） after sham operation with carbon dioxide pneumoperitoneum. Histological changes in liver tissue were observed with hematoxylineosin staining. Liver function was assayed with an automatic biochemical analyzer. Concentration of malonyldialdehyde （MDA） and activity of superoxide dismutase （SOD） were assayed by colorimetry. Activity of adenine nucleotide translocator in liver tissue was detected with the atractyloside-inhibitor stop technique. Expression of hypoxia inducible factor-1 （HIF-1） mRNA in liver tissue was detected with in situ hybridization.RESULTS： Carbon dioxide 60 min could induce liver pneumoperitoneum for injury in rats. Alanine aminotransferase and aspartate aminotransferase were 95.7 ± 7.8 U/L and 86.8 ± 6.9 U/L in 0 h experimental group, and 101.4 ± 9.3 U/L and 106.6 ±8.7 U/L in 1 h experimental group. However, no significant difference was found in total billirubin, albumin, and pre-albumin in the three groups. In 0 h experimental group, the concentration of MDA was 9.83 ±2.53 μmol/g in liver homogenate and 7.64 ± 2.19 μmol/g in serum respectively, the activity of SOD was 67.58±9.75 nu/mg in liver and 64.47 ± 10.23 nu/mg in serum respectively. In 1 h experimental group, the concentration of MDA was 16.57±3.45 μmol/g in liver tissue and 12.49 ±4.21 μmol/g in serum respectively, the activity of SOD was 54.29 ±7.96 nu/mg in liver tissue and 56.31 ±9.85 nu/mg in serum respectively. The activity of ANT in liver tissue was 9.52 ± 1.56 in control group, 6.37± 1.33 in 0 h experimental group and 7.2 8±1.45 （10^-9 mol/min per gram protein） in 1 h experimental group, respectively. The expression of HIF-1 mRNA in liver tissue was not detected in control group, and its optical density difference value was 6.14±1.03 in 0 h experimental group and 9.51 ± 1.74 in 1 h experimental group, respectively. CONCLUSION： Carbon dioxide pneumoperitoneum during the sham operation can induce hepatic injury in rats. The probable mechanisms of liver injury include anoxia, ischemia reperfusion and oxidative stress. Liver injury should be avoided during clinical laparoscopic operation with carbon dioxide pneumoperitoneum.

The complex role of physical exercise and reactive oxygen species on brain

Reactive oxygen species （ROS） are continuously generated during aerobic metabolism and at moderate level. They play a role in redox signaling, but in significant concentration they cause oxidative damage and neurodegeneration. Because of the enhanced sensitivity of brain to ROS, it is especially important to maintain the normal redox state in different types of neuron cells. In last decade it became clear that regular exercise beneficially affects brain function, and can play an important preventive and therapeutic role in stroke, Alzheimer, and Parkinson diseases. The effects of exercise appear to be very complex and could include neurogenesis via neurotrophic factors, increased capillariszation, decreased oxidative damage, and increased proteolyfic degradation by proteasome and neprilysin. Data from our and other laboratories indicate that exercise-induced modulation of ROS levels plays a role in the protein content and expression of brain-derived neurotrophic factor, tyrosinerelated kinase B （TrkB）, and cAMP response element binding protein, resulting in better function and increased neurogenesis. Therefore, it appears that exercise-induced modulation of the redox state is an important means, by which exercise benefits brain function, increases the resistance against oxidative stress, facilitates recovery from oxidative stress, and attenuates age-associated decline in cognition.