Different levels of hyperoxia reversibly induce catalase activity in amphibian tadpoles

Studies about the proposed antioxidant physiological role of the catalase (CAT) enzyme in relation to different environmental oxygen tensions are reported for the first time in amphibian larvae of Discoglossus pictus and Rana ridibunda perezi during their development. The CAT levels of whole tadpoles increased constantly in both species during the larval period, reaching a maximum during the metamorphic climax. All through development, CAT activity levels were always greater in D. pictus than in R. ridibunda perezi. This correlates well with the already reported higher SOD activity and hyperoxia resistance of the D. pictus species when compared to R. ridibunda perezi. Long-term acclimation to different levels of hyperoxia (40, 60, and 100% O2) showed dose-related increases in the CAT activity of D. pictus tadpoles. These increases did not take place when the animals were subjected to acute hyperoxia (24 h). The increase in CAT activity observed after 15 days of acclimation to acute hyperoxia (710 mm Hg: 100% O2) was reversed after 15 additional days of postacclimation to normal air (149 mm Hg O2). When recently metamorphosed frogs were acclimated to acute hyperoxia, significant increases in CAT activity were observed after 15 days, but not after 7 days. The results are interpreted as supporting a protective role for the CAT enzyme in amphibian larvae and froglets against oxygen toxicity.     

Physiological significance of catalase and glutathione peroxidases,and in vivo peroxidation,in selected tissues of the toadDiscoglossus pictus (Amphibia) during acclimation to normobaric hyperoxia

1. Various parameters related to oxidative stress were measured in adult Discoglossus pictus acclimated for 15 days to either normoxia or hyperoxia (PO2 = 710 mmHg). 2. Total weight of the toads and total and relative wet weight of liver, kidneys, lungs and heart were not changed by hyperoxic acclimation. 3. In vivo tissue peroxidation increased in lung, decreased in skeletal muscle, and was not changed in liver, kidney, heart and skin after hyperoxic exposure. 4. Hyperoxic acclimation increased catalase activities in the lung, liver, kidney and heart but not in skeletal muscle and skin. 5. Liver showed higher GSH-peroxidase activity with cumene-OOH than with H2O2 as substrate, whereas lung, skeletal muscle and skin presented similar GSH-peroxidase activities with both substrates. 6. GSH-peroxidase activities did not change between hyperoxic and normoxic animals in liver, lung, skeletal muscle and skin. 7. These results show that catalase, not GSH-peroxidase, is the principal H2O2 detoxifying enzyme involved in the adaptation of D. pictus to hyperoxia.     

Involvement of adrenergic pathways in activation of catalase by myocardial ischemia-reperfusion

In situ rabbit hearts were subjected to 15 min of regional myocardial ischemia, and at various time points of reperfusion, antioxidant enzyme activity and mRNA expression were measured in ischemic and nonischemic myocardium. Catalase activity increased significantly in both ischemic and nonischemic myocardium, peaking at 1 h after reperfusion and then gradually returning to the control level. Northern blot analysis showed enhanced expression of catalase mRNA in both areas. There were no changes in redox status, because glutathione levels were not altered by ischemia-reperfusion (I/R). We also tested whether catalase activation in the heart results from signaling pathways that might influence not only the heart but also other organs. We found that catalase activity in the brain was increased after myocardial I/R and ischemic stress to the intestine was equipotent to myocardial I/R in catalase activation. We next sought to elucidate the possible involvement of the adrenergic system in catalase stimulation induced by ischemic stimuli. After pretreatment with the alpha-adrenergic receptor antagonist prazosin, I/R failed to increase catalase activity in the heart and brain. Intravenous norepinephrine increased catalase activity in the heart, brain, and liver. This study shows that brief I/R activates a signaling mechanism to induce catalase activation in multiple organs and the alpha-adrenergic system is involved as an intermediate pathway in this signal transmission.     

Effect of hyperoxia acclimation on catalase and glutathione peroxidase activities and in vivo peroxidation products in various tissues of the frog Rana ridibunda perezi

Among vertebrates, adult amphibians are known to be especially tolerant to exposure to high environmental oxygen tensions. To clarify the basis for this high O2 tolerance, adult Rana ridibunda perezi frogs were acclimated for 15 days to water-air phases with either 149 mm Hg O2 (normoxia) or 710 mm Hg O2 (hyperoxia). At the end of the acclimation, various morphometric and biochemical parameters related to oxidative stress were measured in seven organs and tissues. Hyperoxia acclimation did not change either the total weight of the animals or the total and relative wet weights of the organs studied, except for the brain, which showed weight increases in the hyperoxic group. In vivo tissue peroxidation increased in the kidney; decreased in the skeletal muscle and skin; and did not change in the liver, lung, brain, and heart after hyperoxic exposures. Whereas liver, lung, and skin showed glutathione peroxidase (GSH-Px) activities with both cumene hydroperoxide (cumene-OOH) and H2O2 as substrates, skeletal muscle only showed H2O2 GSH-Px activity. Hyperoxia acclimation did not change either catalase (CAT) or GSH-Px activities in any organ, except for the liver in which CAT activity was induced by hyperoxia. Thus hyperoxia tolerance in this species does not need the induction of H2O2-detoxifying enzymes in the majority of the organs. It is suggested that the high O2 tolerance of this amphibian species is related to its comparatively high constitutive GSH-Px activities.     

黑线姬鼠与大林姬鼠组织中超氧化物酶和过氧化物酶的分布与活性比较

以黑线姬鼠(Apodemus agrarius)和大林姬鼠(A. peninsulae)为研究对象,采用聚丙烯酰胺凝胶电泳(PAGE)不连续体系的方法,比较分析了心、肝、肾、肌肉、脑、肺6种器官和组织中超氧化物酶(SOD)和过氧化物酶(POD)活性,并建立了2种酶的电泳图谱。结果显示,上述2种酶在黑线姬鼠和大林姬鼠的6种器官和组织中均有表达并表现出明显的特异性,其中,2种鼠中超氧化物酶共分离出迁移率由0.15～0.66的9条电泳谱带,过氧化物酶共分离出迁移率由0.09～0.83的20条电泳谱带。在肝和肺中酶的活性最强,黑线姬鼠6种器官和组织中超氧化物酶活性均强于大林姬鼠,2种鼠组织中过氧化物酶的活性和分布相似,但在同一物种不同器官和组织间过氧化物酶的活性及分布存在明显差异。     

The relationship between total sialic acid levels and antioxidant status in the tadpoles of Bufo viridis and Rana ridibunda ridibunda

Total sialic acid levels (TSA), antioxidant enzymes activities such as superoxide dismutase (SOD), catalase (CAT) and lipid peroxidation (LPO) levels were investigated during the developmental period in tadpoles of the predominantly terrestrial amphibian B. viridis and the predominantly aquatic amphibian R. r. ridibunda. Maximum TSA levels were observed in B. viridis and R. r. ridibunda at the fifth and third week of their development, respectively. SOD and CAT activity variations during development in B. viridis were higher than in R. r. ridibunda. Although SOD activity in B. viridis was higher than R. r. ridibunda at the eighth week, SOD activity increased 19.2-fold in R. r. ridibunda and 10.4-fold in B. viridis between the first and eighth week. CAT activity in R. r. ridibunda did not significantly change (p>0.001) until the fifth week then increased, whereas in B. viridis CAT increased after the third week. In contrast to the rise in the antioxidant enzyme activities, LPO levels tended to decrease during the developmental period. Levels of LPO showed a similar trend until the third week for both species. The minimum LPO levels in B. viridis and R. r. ridibunda were 23+/-1.2 and 146+/-7.3 nmol MDA g(-1) tissue, at the eighth week, respectively. While decreasing LPO levels correlated with increasing antioxidant enzyme activities, TSA tended to decrease after reaching a maximum point.     

Comparative studies on the distribution of rhodanese and beta-mercaptopyruvate sulfurtransferase in different organs of sheep (Ovis aries) and cattle (Bos taurus)

1. The activities of rhodanese and beta-mercaptopyruvate sulfurtransferase (MST) in different organs of sheep and cattle were measured. 2. Liver, kidney, omasum, and rumen were the richest sources of both enzymes. The activities of both enzymes in other organs of the sheep and the cattle decreased in the order of lung, brain, heart, abomasum, lymph node, urinary bladder, spleen, and the skeletal muscle. 3. The activities of both enzymes in most organs of the sheep were higher than the cattle. 4. Both enzymes showed higher activities in the epithelial layers than the muscular layers of rumen, omasum and reticulum. 5. In most of the tissues of both species the level of rhodanese activity was greater than MST.     

Effect of BQ-123 and nitric oxide inhibition on liver in rats after renal ischemia-reperfusion injury

Ischemia-reperfusion (I/R) injury induces an inflammatory response and production of oxygen-derived reactive species which affect many organs including heart, brain, kidney and gastrointestinal tract. The aim of this study was to assess the hepatic changes after renal I/R injury. Male Sprague Dawley rats were subjected to either sham operation or treatment with L-NAME, L-arginine and BQ-123 during 30 min renal ischemia and 2 h reperfusion injury. Hepatic superoxide dismutase (SOD), catalase, glutathione peroxidase (GSH-Px) activities, and thiobarbituric acid-reactive substances (TBARS) and nitric oxide (NO) levels were evaluated to show hepatic response to renal I/R injury. Catalase and SOD activities showed significant differences between the control and the other groups after I/R. On the other hand, GSH-Px activity did not show any significant changes between the control and the other experimental groups mentioned under above conditions. Meanwhile, levels of TBARS were not different between the control and the other experimental groups, whereas NO level showed changes between the control and experimental groups except the one to which endothelin receptor antagonist agent (BQ-123) subjected. Experimental period may not be enough to determine the changes in GSH-Px activity and level of TBARS. However, catalase and SOD activities decreased in experimental groups treated by chemical agents. NO level decreased in chemicalagent-applied experimental groups but not in the group to which endothelin receptor antagonist BQ-123 was applied alone.     

A comparative study of superoxide dismutase in various animal species

1. Superoxide dismutase activity has been determined in liver homogenates of five species. There were no significant differences in the activities of the enzyme in the rat, rainbow lizard, wall gecko and chicken. The activity was significantly lower in the fish. 2. The order of activity of the enzyme in the organs/tissues of the rat was liver greater than kidney greater than heart greater than skeletal muscle greater than brain greater than lung greater than spleen greater than spinal cord greater than retina greater than pancrease greater than lens greater than small intestine. 3. Inhibition studies with cyanide showed that the enzyme in the liver of the various animal species was inhibited by cyanide. 4. The developmental pattern for the enzyme showed no significant changes in the liver of the rat from birth and up to 7 weeks after. However, the activity increased at about 8 weeks and remained constant to adult life.     

Tissue-specific oxidative stress responses in fish exposed to 2,4-D and azinphosmethyl

Species- and tissue-specific defenses against the possibility of oxidative stress and lipid peroxidation were compared in adult fish, Oreochromis niloticus and Cyprinus carpio, exposed to 2,4-dichlorophenoxyacetic acid (2,4-D), azinphosmethyl and their combination for 96 h. Superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase activities were monitored in kidney, brain and gill. In all exposure groups there was a marked increase in SOD activity in gill tissues in both fish species, while it was at the control level in other tissues. The highest elevation of SOD activity by combined treatment was observed in C. carpio. Individual and combined treatments caused an elevation in catalase and GPx activities in kidney of C. carpio. Catalase activity was unaffected in brain of O. niloticus, while GPx activity was decreased after all treatments. Glutathione S-transferase (GST) activity was higher than the control levels in kidney of both fish exposed to pesticides. No significant changes were observed in malondialdehyde level in kidney and brain of C. carpio. Our results indicate that the toxicities of azinphosmethyl and 2,4-D may be related to oxidative stress. Also, the results show that SOD activity in gill and GST activity in kidney may be used as biomarkers for pollution monitoring and indicate that the activities of certain biomarkers in C. carpio are more sensitive to pesticides than those in O. niloticus.     

Hydroperoxide metabolism of amphibia: tissue catalases of leopard frogs

Catalase activities were measured and compared in liver, kidney, heart, and lung of American Leopard Frogs (Rana pipiens complex). The order of activities was found to be liver greater than kidney greater than heart approximately lung. The liver enzyme was found to be inhibited by aminotriazole, cyanide, and azide and appears to peroxidatively oxidize ethanol.     

Phospholipid hydroperoxide glutathione peroxidase: specific activity in tissues of rats of different age and comparison with other glutathione peroxidases

The tissue distribution of phospholipid hydroperoxide glutathione peroxidase (PHGPX) was studied in rats of different ages. In the same samples the activities of Se-dependent glutathione peroxidase (GPX), and non-Se-dependent glutathione peroxidase (non Se-GPX) were also determined using specific substrates for each enzyme. Enzymatically generated phospholipid hydroperoxides were used as substrate for PHGPX, hydrogen peroxide for GPX, and cumene hydroperoxide for non-Se-GPX (after correction for the activity of GPX on this substrate). PHGPX specific activity in different organs is as follows: liver = kidney greater than heart = lung = brain greater than muscle. Furthermore, this activity is reasonably constant in different age groups, with a lower specific activity observed only in kidney and liver of young animals. GPX activity is expressed as follows: liver greater than kidney greater than heart greater than lung greater than brain = muscle, and substantial age-dependent differences have been observed (adult greater than old greater than young). Non-Se-GPX activity was present in significant amount only in liver greater than lung greater than heart and only in adult animals. These results suggest a tissue- and age-specific expression of different peroxidases.     

Superoxide dismutase, glutathione peroxidase, catalase, and lipid peroxidation in the major organs of the aging rats

Glutathione peroxidase (GSh-Px), superoxide dismutase (SOD), catalase (CAT) activities and malon-dialdehyde (MDA) content were determined in heart, liver, kidney and brain of rats. Two different age groups (4 months; 24 months) were considered. GSH-Px and SOD activities decrease significantly for the aged liver and kidney. During aging, the activity of catalase increase in cardiac muscle and, in contrast, decrease in other organs. Lipids peroxidation, expressed in term of MDA formation, decrease in all the organs of the aged rats. The results indicate that: 1) the liver and kidney antioxidative defense decrease with age; 2) the enzymatic activities evolve in a different manner for different enzymes and organs. Furthermore, the results suggest that there is not any correlation between the SOD, CAT, and GSH-Px activities and the peroxidative status of the organs; thus, the age-related increase in the MDA content proposed as a criterion of aging process should be considered with caution.     

小鼠组织中过氧化氢酶的活性与年龄的关系

为观察小鼠组织中过氧化氢酶的活性与年龄的关系,采用高锰酸钾滴定法测定不同年龄(1、4、18月龄)小鼠肝、肾、肺、心、脾、胃、脑组织中过氧化氢酶的活性。结果显示:小鼠过氧化氢酶在不同组织中活性不同,活性高低顺序基本表现为:肝>肾>肺>心、脾、胃>脑;小鼠肺、心、脾、胃、脑各组织中过氧化氢酶的活性在1～4月龄间随年龄增加而增加,在4～18月龄间随年龄增加而降低;小鼠肝、肾组织中过氧化氢酶的活性在1～4月龄间与年龄相关性不显著,在4～18月龄间随年龄增加而降低。结果表明,小鼠肝、肾、肺、心、脾、胃、脑等组织中过氧化氢酶的活性随年龄变化而变化,机体过氧化氢酶活性的降低与机体衰老密切相关。     

Carbohydrate contents, and glycosidase and glycosyl transferase activities in tissues from streptozotocin diabetic mice

The contents of hexoses and hexosamines in brain, liver, and kidney of streptozotocin diabetic mice are significantly increased in comparison to the controls. These differences for hexoses contents in the heart are not significant. N-acetyl-beta-D-glucosaminidase and beta-D-glucosidase activities in brain, liver and kidney of diabetic mice are significantly higher when compared to the controls. However, beta-D-galactosidase activity is significantly lower in brain, liver, spleen and kidney of the diabetic mice, in comparison to the controls and similar in heart. alpha-D-Mannosidase activity of diabetic mice is significantly increased in spleen and heart and significantly decreased in liver and kidney. alpha-L-Fucosidase of diabetic mice shows higher activities, with significant differences, in liver and spleen; however, in heart and kidney the activities are significantly lower. Brain sialyltransferase and galactosyltransferase activities are significantly increased in diabetic mice; but for heart and kidney these differences are not significant. The activity for brain and kidney fucosyltransferase is not significant and that for the other assayed organs is significantly higher in comparison to the controls.     

Evaluation of gender-related differences in various oxidative stress enzymes in mice

Oxidative stress caused by redundant free radical, lipid oxygen and peroxide usually results in the pathogenesis of various diseases, which can be alleviated by cellular antioxidant enzymes. According to statistics, there are different incidence rates of some diseases depending on the gender. The present study aimed to investigate potential gender-related differences of antioxidant enzymes in mice. The activities of glutamate-cysteine ligase (GCL), glutathione reductase (GR), glutathione peroxidase (GPx), glutathione S-transferase (GST), superoxide dismutase (SOD) and catalase (CAT) in the kidney, brain, lung and heart of both male and female mice were determined. Our results showed that GPx and GCL activities were higher in female kidney and brain than those in male. On the other hand, the activities of SOD were higher in female brain and lung than those in male. Moreover, female kidney appeared to show higher activities of CAT than the male kidney. But the activities of GCL and GPx were higher in male heart than those in female. Taken together, our results demonstrate that there are gender-related differences in the activities of cellular antioxidant enzymes in various important organs in mice. Variations in such enzymes may be the explanation for some gender-related diseases.     

Corticosteroid side-chain isomerase in mouse organs: kinetic and immunologic studies

We have investigated the distribution of corticosteroid side-chain (CSC) isomerase in the tissues of mice using as criteria its enzyme activity and immunoreactivity with monospecific polyclonal antibodies generated in rabbits. CSC isomerase was present in all organs examined. The liver and kidney contained the highest activity. The strain-dependent differences that we had previously reported for liver (i.e., BALB/c greater than C57BL/6) extended to the other organs, including the kidney, brain, heart, muscle, pancreas, testis, thymus, and lung. Western blot analysis showed a single antigen, identical in all tissues, corresponding in mobility to purified CSC isomerase. The intensities of the bands were generally proportional to enzyme activities. Titration of homogeneous enzyme with the IgG fraction of antiserum (unfractionated serum had some CSC isomerase activity) caused an increase in activity, followed by rapid inactivation after the addition of more antiserum. The broad distribution of CSC isomerase suggests that the ketol-aldol interconversion of the CSC may play a role other than, or in addition to, initiating metabolic inactivation of corticosteroids.     

Effects of brief starvation on brain protease activity

Changes in the activity of proteases (cathepsin D and calpains) caused by 48-h food withdrawal were studied in the brain, liver, kidney, spleen, and heart of 3-, 12-, and 24-month-old Fischer rats. Cathepsin D activity was similar in brain, liver, and heart of control animals; in kidney it was 5-fold higher and in spleen about 10-fold higher. With age, activity increased in all organs tested except spleen. Brief starvation caused no change of cathepsin D activity in brain, but caused an increase in liver and a decrease in spleen. Neutral proteolytic activity in control was highest in the pons-medulla-cerebellum fraction of brain, and activity in liver and heart was below that in brain. Activity increased with age in brain and decreased in other organs. Brief starvation in young animals caused an increase in activity in brain, and a decrease in liver and spleen. Isolated calpain II activity was high in control brain. It increased with age in the cerebrum. Brief starvation resulted in a decrease in the brain. The results indicate that the protease content of the brain is altered with age and in malnutrition, with changes not being the same for all proteases, and changes in brain being different from those in other organs.Special issue dedicated to Dr. Louis Sokoloff.     

Sex-specific divergence of antioxidant pathways in fetal brain,liver, and skeletal muscles

The sex-specific divergence of antioxidant pathways in fetal organs of opposite-sex twin is unknown and remains urgently in need of investigation. Such study faces many challenges, mainly the ethical impossibility of obtaining human fetal organs. Opposite-sex sheep twins represent a unique model for studying a sex dimorphism for antioxidant systems. The activity of total superoxide dismutase (SOD), SOD1, SOD2, glutathione peroxidase (GPX), glutathione reductase (GR) and catalase (CAT), the content of total glutathione, reduced glutathione (GSH), and oxidized glutathione (GSSG) were measured in brain, lung, liver, kidney, and skeletal muscles of female and male fetuses collected from sheep twin pregnancies at day 65 of gestation. Lipid peroxidation was assessed by measuring melondialdehyde (MDA) tissue content. Male brain has greater total SOD and SOD1 activities than female brain. Female liver has greater SOD2 activity than male liver. Male liver has greater GR activity than female liver. Male liver has higher total GSH and GSSG content than female liver. Male skeletal muscles have higher total GSH, GSH, and GSSG content than female skeletal muscles. Female brain and liver have higher MDA content than male brain and liver. This is the first report of a sex dimorphism for fetal organ antioxidative pathways. Brain, liver, and skeletal muscles of male and female fetuses display distinct antioxidant pathways. Such sexually dimorphic responses to early life oxidative stress might be involved in the sex-related difference in fetal development that may have a long-term effect on offspring. Our study urges researchers to take into consideration the importance of sex as a biologic variable in their investigations.     

Effects of dietary carbohydrate intake on antioxidant enzyme activity and copper status in the copper-deficient streptozotocin (STZ) diabetic rat

The aim of this study was to investigate how dietary lactose, compared with sucrose, in association with copper deficiency influences the antioxidant and copper status in the diabetic rat. Two groups of male rats (n = 12) were fed copper-deficient diets containing either 300 g/kg of sucrose or 300 g/kg of lactose in a pair-feeding regime for 35 days. Six rats from each group were injected with streptozotocin to induce diabetes. After a further 16 days the animals were killed and the liver, heart, and kidney removed for the measurement of copper levels and the activities of antioxidant and related enzymes. Diabetes resulted in higher hepatic and renal copper levels compared with controls. The copper content of the heart and kidney in diabetic rats consuming sucrose was also significantly higher than in those consuming lactose. Catalase activity in the liver, heart, and kidney was significantly increased in diabetic rats compared with controls. Hepatic glutathione S-transferase and glucose-6-phosphate dehydrogenase and cardiac copper zinc superoxide dismutase activities were also higher in diabetes. Sucrose, compared with lactose feeding, resulted in higher cytochrome c oxidase and glutathione peroxidase activities in the kidney while glucose-6-phosphate dehydrogenase activity was lower. The combination of lactose feeding and diabetes resulted in significantly higher activities of cardiac managanese superoxide dismutase and catalase and renal manganese superoxide dismutase and glucose-6-phosphate dehydrogenase. These results suggest that sucrose consumption compared with lactose appears to be associated with increased organ copper content and in general decreased antioxidant enzyme activities in copper-deficient diabetic rats.