Protection by free oxygen radical scavenging enzymes against glucose-induced embryonic malformations in vitro

Summary This study addresses the possibility that the teratogenic effects of a diabetic pregnancy are associated with increased embryonic activities of free oxygen radicals. Rat embryos were cultured in 50 mmol/l glucose for 48 h and subsequently showed pronounced growth retardation and severe malformations. The enzyme inducer citiolone and the free oxygen radical scavenging enzymes Superoxide dismutase, catalase and glutathione peroxidase protected against the disturbed growth and development of the embryos at 50 mmol/l glucose when added to the culture media. Enzymatic measurements indicated that citiolone induced an increased activity of superoxide dismutase in the embryonic tissues and that the added enzymes were taken up by both the yolk sac and the embryo proper. The protection against embryonic maldevelopment was thus conferred by agents that increased the free oxygen radical scavenging capacity of the embryonic tissues. The results suggest that a high glucose concentration in vitro causes embryonic dysmorphogenesis by generation of free oxygen radicals. An enhanced production of such radicals in embryonic tissues may be directly related to the increased risk of congenital malformations in diabetic pregnancy.This study was presented in part at the 26th Annual Meeting of the European Association for the Study of Diabetes, Copenhagen, Denmark, 10–14 September 1990     

维生素E对D-半乳糖亚急性中毒拟衰老模型鼠氧自由基及相关生化指标的影响

目的研究维生素E(VE)对D-半乳糖(D-gal)亚急性中毒拟衰老模型鼠自由基产生及相关生化指标的影响。方法昆明小鼠颈背部皮下注射D-gal40mg·kg-1.d-1制备D-gal亚急性中毒导致的衰老鼠模型。将模型鼠分为模型组和高、中、低剂量VE组(分别灌胃60、30、15mg·kg-1.d-1VE),10w后杀鼠。采用硫代巴比妥酸(TBA)法检测血清中丙二醛(MDA)含量,黄嘌呤氧化酶法检测血清中总超氧化物歧化酶(SOD)活性;采用ISP半自动生化分析仪检测血清中血糖(Glu)、总胆固醇(TC)、甘油三酯(TG)的含量。结果模型鼠血清中MDA含量、Glu、TC、TG含量显著高于正常对照组,SOD含量显著低于正常对照组(均P<0.05),高、中、低剂量VE组血清MDA含量显著低于模型对照组,总SOD含量显著高于模型对照组(均P<0.05)。高、中、低剂量VE组小鼠血清Glu、TC、TG含量与模型对照组无显著差异。结论VE可以对衰老鼠的氧自由基损伤发挥保护作用,为临床将VE作为一种抗衰老药物应用提供了进一步的试验依据。     

氧自由基在小儿病毒性心肌炎发病中的作用和硫酸锌治疗作用研究

为探讨氧自由基（OFR）在病毒性心肌炎（VMC）发病中的作用及硫酸锌（ZnSO4)对OFR损伤心肌的治疗作用，进行了相关临床研究和动物实验。结果显示，61例VMC患儿血中过氧化物歧化酶（SOD）降低；丙二醛(MDA）及左室 射血分数（LVEF）升高；SOD与CK－MB呈负相关，与LVEF呈正相关；MDA与CK－MB呈正相关，与LVEF呈负相关。ZnSO4与维生素C均可使心肌细胞存活力升高，LDH浓度降低，SOD活力升高，MDA降低；Na-KATP酶和CaATP酶活力升高。大剂量ZnSO4治疗VMC的疗效好于大剂量维生素C和小剂量ZnSO4.     

The oxygen free radical system: from equations through membrane-protein interactions to cardiovascular injury and protection.

Highly toxic oxygen radicals and their metabolites have been implicated in the pathogenesis of ischaemia/reperfusion injury. These reactive oxygen species include the superoxide anion, hydrogen peroxide, hydroxyl radical, and singlet oxygen. The central theme of this review is first to discuss the basic mechanisms of free radical generation from various potential sources, to point out and emphasise the growing importance of the role of singlet oxygen, and then to discuss in depth membrane-protein interactions that ultimately lead to myocardial damage and dysfunction. With this background, we highlight several novel therapeutic strategies aimed at interrupting the oxygen free radical mediated component of ischaemia/reperfusion injury. It is hoped that this thesis will then serve as a future impetus to challenge these hypotheses and further build on this truly unique system that has assumed such an important role in the pathophysiology of myocardial ischaemia/reperfusion and inflammation. "To those of us who are humbly exploring the mysteries of science, we must project our findings and model our systems. For if correct, we have made a small contribution and, if wrong, we have forced others to eventually think." A V Hill, on the occasion of the 50th anniversary of E H Starling's Linacre lecture (University College, London, 1968).     

Involvement of peripheral benzodiazepine receptors in the protection of hematopoietic cells against oxygen radical damage

Several putative functions have been attributed to the peripheral benzodiazepine receptor (PBR), but its precise physiologic role has not been elucidated. In the present study, we investigated PBR function by quantifying this receptor in leukocyte subsets from healthy donors and in leukemic blasts from lymphoid and myeloid lineages. Using a monoclonal antibody (MoAb) directed against the human PBR and a quantitative flow cytometric assay, we found that phagocytic cells from healthy donors displayed a higher level of PBRs than lymphocytes or natural killer (NK) cells. Among the lymphoid lineage, thymocytes and IgD-negative B cells expressed the lowest levels. However, because of the wide heterogeneity of PBR levels among 42 acute or chronic lymphoid and myeloid leukemias, it was not possible to assign PBR expression to a stage of maturation or a cell lineage. Although the PBR displayed a mitochondrial subcellular localization, its expression was not correlated with the mitochondrial content, suggesting a modulation of PBR density at the level of the mitochondria. This modulation was confirmed when we studied in detail the PBR expression during T-cell development by both flow cytometry and confocal microscopy. We found that the PBR was expressed with a bimodal profile during T-cell development, identical to the one observed with the proto-oncogene, Bcl- 2. The high similarity in the expression of both the PBR and the Bcl-2 proto-oncogene in T-cell and B-cell subsets, their common mitochondrial localization, and the observation of high quantities of PBR in phagocytic cells, which are known to produce high levels of radical oxygen species, suggested that PBRs may participate in an antioxidant pathway. Indeed, a strong correlation was established between the ability of hematopoietic cell lines to resist H202 cytotoxicity and their level of PBR expression. Demonstration of the role of PBR in the protection against H202 was obtained by transfecting JURKAT cells with the human PBR cDNA. Transfected cells exhibited increased resistance to H202 compared with wild-type cells, suggesting that PBR may prevent mitochondria from radical damages and thereby modulate apoptosis in the hematopoietic system.     

The oxygen free radical system: potential mediator of myocardial injury

The sequential univalent reduction of oxygen gives rise to very reactive intermediate products including superoxide anion radical, hydrogen peroxide and free hydroxyl radicals. Normally, the tissue concentration of these intermediate products of oxygen is severely limited; however, if oxygen free radicals are produced in excess of the capacity of the tissues to eliminate them, they may cause serious damage. The biochemistry and possible sources of free radical generation in animal models of ischemic/reperfusion injury are reviewed. The ability of scavengers of oxygen free radicals to improve mechanical, mitochondrial and sarcoplasmic reticulum function in animal models of ischemic/reperfusion injury suggests that oxygen free radicals are partly responsible for myocardial injury in these models. Future research should be directed at establishing the relevance of oxygen radical-mediated myocardial injury in the experimental setting to analogous clinical situations.     

Coronary artery disease - free radical damage, antioxidant protection and the role of homocysteine

Traditional risk factors for coronary artery disease (CAD) can only explain approximately two thirds of observed clinical events. This has maintained interest in other nutritional and biochemical factors that might contribute to the underlying pathophysiology of vascular disease. Two such factors are dietary antioxidants and plasma homocysteine. Established risk factors such as hypertension, smoking and diabetes mellitus are all associated with increased oxidative stresses due to excess free radical activity in the vascular wall. This may facilitate the development of vascular disease because of (i) increased oxidation of low-density lipoprotein (LDL) particles which increases their propensity to deposition in the vascular wall, (ii) inactivation of endotheliumderived nitric oxide, and (iii) direct cytotoxicity to endothelial cells. Protective antioxidant molecules include vitamin C and vitamin E of which the latter is lipid soluble and is the primary antioxidant defence in circulating LDL particles. Epidemiological studies have suggested strongly that individuals who have high circulating concentrations or dietary intake of natural antioxidant vitamins are protected against vascular disease events (18). Furthermore, many studies have demonstrated a beneficial effect of natural and synthetic antioxidants on surrogate markers of vascular disease such as endothelial function and lipoprotein oxidation. However, large prospective randomized controlled intervention trials, mostly involving vitamin E (e.g. CHAOS, HOPE (22)), have failed to demonstrate any beneficial effect upon vascular mortality in high risk individuals. Possible reasons for these disappointing results include the pro-oxidant effects of high dose antioxidant supplements, particularly in patients with established vascular disease. Homocysteine is a sulphydryl-containing amino acid derived from the demethylation of dietary methionine. Epidemiological studies over 30 years have shown that increased concentrations of homocysteine are associated with vascular disease. This link is independent of other risk factors, is consistent across many studies and is strongly dose-related. Recently, evidence has accumulated to suggest that this link is also biologically plausible because homocysteine promotes oxidant injury to the vascular endothelium, impairs endothelium-dependent vasomotor regulation and may also alter the coagulant properties of the blood. Plasma homocysteine levels can be reduced by dietary supplements of folic acid and B vitamins. Studies are currently being undertaken to examine the impact of these vitamins in high risk patients and, thereby, establish a causative role for homocysteine in promoting vascular events.     

Effect of thyroid hormones on mitochondrial oxygen free radical production and DNA oxidative damage in the rat heart

Mitochondria seem to be involved in oxygen radical damage and aging. However, the possible relationships between oxygen consumption and oxygen radical production by functional mitochondria, and oxidative DNA damage, have not been studied previously. In order to analyze these relationships, male Wistar rats of 12 weeks of age were rendered hyper- and hypothyroid by chronic T(3) and 6-n-propyl-2-thiouracil treatments, respectively. Hypothyroidism decreased heart mitochondrial H(2)O(2) production in States 4 (to 51% of controls; P<0.05) and 3 (to 21% of controls; P<0.05). In agreement with this, 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) decreased in the heart genomic DNA of hypothyroid animals to 40% of controls (P<0.001). Studies with respiratory inhibitors showed that the decrease in oxygen radical generation observed in hypothyroidism occurred at Complex III (mainly) and at Complex I; that decrease was due to the presence of a lower free radical leak in the respiratory chain (P<0.05). Hyperthyroidism did not significantly change heart mitochondrial H(2)O(2) production since the increase in State 4 oxygen consumption in comparison with control and hypothyroid animals (P<0.05) was compensated by a decrease in the free radical leak in relation to control animals (P<0.05). In agreement with this, heart 8-oxodG was not changed in hyperthyroid animals. The lack of increase in H(2)O(2) production per unit of mitochondrial protein will protect mitochondria themselves against self-inflicted damage during hyperthyroidism.     

Influence of acute alcohol exposure on hemorheological parameters and platelet function in vivo and in vitro

We have analysed the influence of acute alcohol exposure in vivo and in vitro on blood flow properties and platelet function. 12 healthy male volunteers drank either 4.36 ml red wine/kg body weight (=0.5 g ethanol/kg) or water at 06.00 p.m. under fasting conditions. Blood was drawn immediately before, and 1, 2, 4 and 13 h after alcohol ingestion. Alcohol had a detectable osmotic effect on erythrocytes; the mean cellular volume (MCV) was significantly smaller 1-4 h after ingestion. Whole blood viscosity remained unaffected, but blood viscosity at a standardized Hct of 45% measured at a high shear rate (94.5 s(-1)) was increased 2 h after wine ingestion. In the morning, 13 h after wine drinking, platelet aggregation measured with a platelet function analyser PFA-100 was increased to a greater extent than after water drinking. In vitro, no effect was seen when blood was incubated with 0, 12.5, 25, 50 and 100 mmol/l ethanol for 1 h at 37 degrees C. We conclude that an acute exposure to alcohol has only modest effects on hemorheological parameters and platelet aggregation in vivo and no effect in vitro, which suggests that other factors must be involved in both beneficial and harmful effects of wine drinking.     

In vitro evaluation of free radical scavenging activity of Codariocalyx motorius root extract

ObjectiveTo determine the phenolic content in Codariocalyx motorius root extract and to evaluate its antioxidant properties using various in vitro assay systems.MethodsThe antioxidant activity was evaluated based on scavenging of 1,1-diphenyl-2-picrylhydrazyl, hydroxyl radicals, superoxide anions, nitric oxide, hydrogen peroxide, peroxynitrite, reducing power and by inhibition of lipid peroxidation which was estimated in terms of thiobarbituric acid reactive substances.ResultsThe root extract of the Codariocalyx motorius (C. motorius) exhibited potent total antioxidant activity that increased with increasing amount of extract concentration, which was compared with standard drug such as quercetin, butylated hydroxytoluene, tocopherol at different concentrations. The different concentrations of the extracts showed inhibition on lipid peroxidation. In addition, the extracts had effective reducing power, free radical scavenging, super oxide anion scavenging, nitric oxide scavenging, lipid peroxidation, and total phenolic content depending on concentration. High correlation between total phenolic contents and scavenging potential of different reactive oxygen species (r²=0.831–0.978) indicated the polyphenols as the main antioxidants.ConclusionsCodariocalyx motorius (C. motorius) root possess the highly active antioxidant substance which can be used for the treatment of oxidative stress-related diseases.     

D-半乳糖诱发氧自由基升高对大鼠动脉衰老的影响

目的观察D半乳糖诱发氧自由基升高对大鼠颈动脉顺应性和腹主动脉脂褐素含量的影响。方法大鼠皮下注射D半乳糖140mg/kg连续7w,造成氧自由基升高动物模型。分别测定模型组与对照组大鼠血浆MDA、SOD水平。同时采用恒速注入流体方法测定大鼠颈动脉血管段的顺应性和荧光图像分析法测定腹主动脉脂褐质含量。结果模型组较对照组MDA含量显著升高(P<001),SOD略有下降。模型组血管顺应性低于对照组,其中弹性面积有显著性差异(P<005)。模型组腹主动脉脂褐质荧光强度显著高于对照组(P<005)。结论氧自由基是造成动脉衰老的重要因素。     

Activities of free oxygen radical scavenger enzymes in human liver

Activities of superoxide dismutase, catalase and glutathione peroxidase were measured in liver biopsy specimens from patients with various liver diseases, including six with chronic persistent hepatitis, nine with chronic active hepatitis, nine with non-alcoholic cirrhosis, eight with alcoholic cirrhosis and eight with acute hepatitis. Measurements from ten patients without liver disease were used as controls. Levels of total superoxide dismutase activity in the chronic active hepatitis and non-alcoholic cirrhosis groups were significantly lower than those in the controls (p less than 0.01 and p less than 0.01, respectively). The level of total superoxide dismutase activity in the acute hepatitis group was significantly higher than that in the control group (p less than 0.01). The levels of Cu,Zn-superoxide dismutase activity in all the experimental groups, except for the chronic persistent hepatitis group, were significantly lower than those in the controls (p less than 0.01 in all groups). The levels of Mn-superoxide dismutase activity in the alcoholic cirrhosis and acute hepatitis groups were significantly higher than those in the controls (p less than 0.01 and p less than 0.01, respectively), although no difference in the level of this enzyme was seen among the controls, chronic persistent hepatitis, chronic active hepatitis and non-alcoholic cirrhosis groups. The levels of catalase activity in the groups with chronic active hepatitis, non-alcoholic and alcoholic cirrhosis and acute hepatitis were significantly lower than those in the controls (p less than 0.01 in all groups). Glutathione peroxidase activity showed no difference among the groups.(ABSTRACT TRUNCATED AT 250 WORDS)     

Ozonized autohemotransfusion improves hemorheological parameters and oxygen delivery to tissues in patients with peripheral occlusive arterial disease

Twenty-seven subjects suffering from peripheral occlusive arterial disease (POAD, clinical stage II-III according to Fontaine) were enrolled in this study to evaluate the effect of oxygen-ozone therapy upon hemorheological parameters and hemoglobin-oxygen affinity in patients with POAD. All patients underwent a major ozonized autohemotransfusion consisting of the slow reinfusion of 100 ml of autologous blood, previously exposed to a O(2)-O(3) mixture in a glass box for 10 min. Whole blood viscosity, erythrocyte filterability, hematocrit, and fibrinogen levels were assessed at the basal time and 30 min after the reinfusion of ozonized blood. At the same time p50 standard (p50std) values (an indicator of hemoglobin-oxygen affinity) and plasma values of malonyl dialdehyde (MDA, an indicator of lipid peroxidation) were evaluated. At the baseline, patients had significantly higher ( p<0.05- p<0.001) whole blood viscosity, MDA, and p50std values and significantly lower blood filterability ( p<0.01) as compared with 20 matched healthy volunteers (controls). Thirty minutes after the end of a major autohemotransfusion, whole blood viscosity significantly decreased ( p<0.01). This was accompanied by a significant fall in plasma fibrinogen level ( p<0.01) with no change in hematocrit. Blood filterability, MDA plasma level, and p50std values increased significantly at the same time ( p<0.01- p<0.005). The 2,3-DPG value did not change significantly. No significant changes occurred when the same patients received a non-ozonized autohemotransfusion (control test). In conclusion, ozonized autohemotransfusion may be useful to improve both the poor rheological properties of the blood and the oxygen delivery to tissues in patients suffering from POAD.     

卡维地洛对氧自由基所致心肌细胞L型钙电流异常的保护作用

目的　研究卡维地洛对氧自由基引起的豚鼠单个心室肌细胞L型钙电流异常的保护作用。方法　采用全细胞膜片钳技术 ,观察 0 5mmol/L的H2 O2 引起单个豚鼠心室肌细胞L型钙电流改变及预先应用 0 5 μmol/L卡维地洛对这种改变的影响。结果　 0 5 μmol/L卡维地洛对正常豚鼠心室肌细胞L型钙电流及其通道动力学影响不显著。 0 5mmol/LH2 O2 作用下 ,豚鼠心室肌细胞L型钙电流峰值明显降低 (P <0 0 0 1) ,电流 电压曲线上移 ,通道稳态激活曲线和稳态失活曲线左移 ,通道恢复时间明显延长 (P <0 0 0 1)。预先给予 0 5 μmol/L卡维地洛 ,明显减轻H2 O2 对L型钙电流的抑制作用 (P <0 0 1) ;并且可减轻H2 O2 对L型钙通道动力学的异常影响。结论　卡维地洛可减轻氧化应激对心肌细胞L型钙电流的影响 ,这可能是其治疗心力衰竭的机制之一     

氧自由基与家兔心肌缺血—再灌注后发生心律失常的关系

目的探讨再灌注性心律失常的发生机制.方法用家兔制成缺血-再灌注模型,测定缺血-再灌注心肌的丙二醛含量,同时在实验过程中监测心电图.再灌注性心律失常的严重程度用心律失常评分判定.结果缺血-再灌注心肌的丙二醛明显高于对照组(76.25±42.92vs 30.55±10.65,P＜0.05),且与心律失常评分明显正相关(r=0.808,P＜0.01).结论心肌缺血-再灌注后大量氧自由基产生,可能是导致再灌注性心律失常的原因之一.     

Evaluation of hemorheological parameters and red cell morphology in hypertension

The aim of our study was to evaluate hemorheological parameters in two groups of patients both suffering from essential hypertension compared with an homologous group of subjects not suffering from hypertension; the 1st group was composed of 16 patients (8 females and 8 males, mean age 65.6 +/- 16.5) suffering from essential hypertension; the 2nd one of 26 patients (8 females and 18 males, mean age 74.3 +/- 11.7) suffering from essential hypertension and cerebral or cardiac ischemia in a chronic phase. The group of controls was composed of 20 subjects (mean age 50.5 +/- 11.5). In all these subjects we evaluated: blood viscosity, hematocrit, plasmatic fibrinogen, red cell morphology according to Zipursky-Forconi method and blood pressure. Our results show that blood viscosity and fibrinogen were statistically increased relative to controls. Comparison between these groups leads us to observe that blood viscosity and fibrinogen are slightly higher in the first group in a statistically significant way (7.5 +/- 1.1 cPs 10 s(-1) 1st group, 7.9 +/- 1.05 cPs 10 s(-1) 2nd group; 362.2 +/- 167.3 mg% 1st group, 384.6 +/- 106.9 mg% 2nd group). Blood pressure was higher in the second group. The study of red cell morphology in all the patients showed a prevalence in the percentage of discocytes, cells which have less deformability compared to bowls. The study demonstrated EMI (Erythrocyte Morphology Index) decreased in a statistically significant way compared to controls (0.70 +/- 0.03 1st group; 0.65 +/- 0.02 2nd group; 1.2 +/- 0.09 control group). In subjects suffering from essential hypertension with end-organ damage EMI further decreases. So we observed that hypertension is also delineated by the increase in the discocytes percentage which results in reduction of the red cell deformability. In conclusion, when hypertension causes end-organ damage, the hemorheological alterations, which implicate a worsening in microcirculation, are more evident.