Influence of copper intake and inflammation on rat serum superoxide dismutase activity levels

Serum superoxide dismutase (SOD) activity concentrations, though small compared to tissue levels, could contribute to extracellular superoxide radical detoxification and act as indicators of copper status. The present study identified the response of rat serum SOD activity contents to marginal and deficient copper intakes and to inflammation. Rats fed copper-deficient diet (less than 0.2 mg/kg Cu) for 5 wk displayed serum SOD activity contents that were only about 20% of those found in rats fed copper-supplemented diet (6.0 mg/kg Cu). Activities in rats fed a marginal diet (1.5 mg/kg Cu) were about 55% of those in the adequate rats. Turpentine-induced inflammation lowered serum SOD in rats within each dietary group. However, the change in the marginal group was not statistically significant. Based on chromatographic characterizations and inhibitor studies, rat serum SOD activity seemed to result primarily from a copper protein other than ceruloplasmin, Cu-Zn SOD or the recently discovered tissue extracellular SOD. In conclusion, low copper intake and inflammation may compromise extracellular defenses against superoxide. In addition, serum SOD activities could provide a non-ceruloplasmin-related means of assessing copper status, but nondietary variables can also affect these SOD values.     

Changes in activity of the Cu-Zn superoxide dismutase enzyme in tissues of the rat with changes in dietary copper.

The effects of dietary copper level on tissue activities of the copper containing superoxide dismutase (CuSOD) were investigated, and these activities related to those of other copper containing enzymes particularly cytochrome oxidase. Male weaning rats were fed a basal diet (containing 0.8 mg Cu/kg) or this diet supplemented with 4 or 24 mg Cu/kg. After 6 weeks, rats fed the basal diet were then repleted using the high copper diet. In the two copper supplemented groups, no differences were observed in any of the parameters measured. In these groups, tissue activities of CuSOD were in the order of liver greater than kidney greater than RBC greater than testis greater than heart greater than brain greater than lung greater than muscle. In the basal group, CuSOD activity decreased in liver; RBC and heart to 14, 25, and 61%, respectively, of control activities after 6 weeks' depletion; tissues other than brain or muscle showed smaller but significant changes. Conversely, heart and muscle cytochrome oxidase activities decreased to 30 and 45% of control activity and liver to 70%. With repletion, CuSOD activities in liver and heart increased more rapidly than did cytochrome oxidase activities. It is concluded that liver CuSOD activity, which is normally high, is greatly reduced with little change in cytochrome oxidase activity; the reverse is found for heart and muscle tissue. The relevance of these changes to the maintenance of tissue integrity is discussed.     

No effects of low copper intake o rat mammary tissue superoxide dismutase 1 activity and mammary chemical carcinogenesis

Variations in copper‐containing superoxide dismutase (SOD) 1 are hypothesized to produce variations in resistance to carcinogenesis, particularly in mammary tissue. Therefore, it is reasonable to speculate that low copper intake, which causes low SOD 1 activities in various tissues, would cause poor resistance to mammary carcinogenesis. This idea was tested using female rats fed diets either low or adequate in copper (<0.5 or 8 mg copper/kg diet) plus or minus oral gavage with the mammary carcinogen 7,12‐dimethyl‐benz[a]anthracene (5 mg/kg, given 5 wk after dietary modification, 28 wk before sacrifice). Low copper intake produced low activities of two serum copper enzymes: ceruloplasmin and extracellular SOD. In contrast, low copper intake did not affect mammary tissue SOD 1 activities, nor did it statistically influence any of several parameters of 7,12‐dimethyl‐benz[a]anthracene‐induced mammary carcinogenesis.     

Dietary copper and copper dependant superoxide dismutase in hepatic prostaglandin synthesis by rat liver homogenates

The influence of dietary copper, Cu²⁺ additions and Cu/Zn SOD additions on liver homogenate PGE2 and PGF2α production was examined in rats. Dietary copper deficiency significantly decreased both PGE2 and PGF2α synthesis in liver homogenates. Cu²⁺ additions to 10 μM or 100 μM (final) had no effect on PGE2 or PGF2α synthesis in either deficient or control liver homogenates. Addition of purified Cu/Zn SOD to a concentration approximately equal to that of control liver, significantly increased PGE2 and PGF2α synthesis in both control and copper deficient liver homogenates. Addition of purified Cu/Zn SOD to a concentration approximately three times that of control liver significantly depressed PGE2 and PGF2α synthesis in copper-deficient liver homogenates. In all cases addition of arachidonic acid (100 μM, final) had no influence on the above listed responses. Both PGE2 and PGF2α production by liver homogenates showed a significant correlation with SOD. Both dietary copper and added Cu/Zn SOD, but not added Cu²⁺, influence PGE2 and PGF2α production in liver homogenates.     

Role of copper in the regulation and accumulation of superoxide dismutase and metallothionein in rat liver

Weanling male Sprague-Dawley rats were fed one of four diets that varied in Cu, Zn or Cd content. To the control diet (I) Cu, Zn and Cd were added at 10, 100 and 0 mg/kg diet, respectively. Diets II and III also contained 10 mg/kg of dietary Cu, except that Zn was elevated to 1000 mg/kg for diet II, or Cd was added at 10 mg/kg for diet III. Diet IV was deficient in Cu (less than 1 mg/kg) with Zn at 100 mg/kg and no added Cd. At wk 6 postweaning, half of the rats fed diets I and IV were injected once with Cd acetate (5 mg Cd/kg body weight). The immediate response to Cd injection was an increase in metallothionein accumulation (three- to fourfold) and in Cu,Zn superoxide dismutase (SOD) accumulation (1.2- to 1.5-fold) in liver. SOD was estimated in an ELISA. These responses were not influenced by a change in Cu status (I vs. IV). However, in functional assays, SOD enzymatic activity was about half that of the control values. In this regard, SOD appears to be given high priority with respect to the utilization of cellular Cu, i.e., a 10-fold reduction in hepatic Cu only resulted in a twofold reduction in SOD activity and the amount of apoenzyme remained at normal levels.     

Alteration of guinea pig erythrocyte superoxide dismutase activity by dietary antioxidants

An improved method for the measurement of superoxide dismutase (SOD) activity in guinea pig erythrocytes was developed. Alteration of guinea pig erythrocyte superoxide dismutase activity by the dietary antioxidants ascorbic acid and selenium was investigated. Erythrocyte SOD activity was directly related to the ascorbic acid intake of guinea pigs fed 0.05 ppm of selenium. Dietary levels of ascorbic acid were 0, 200 and 400 mg/kg). In guinea pigs fed 0.20 ppm of selenium, there was an increase in superoxide dismutase activity only in the group of animals fed the 400 mg ascorbic acid/kg of diet. Results suggest that substantial protection from deleterious O2-. can be provided by changes in dietary ascorbic acid.     

Plasma zinc, copper, and erythrocyte superoxide dismutase in children with phenylketonuria.

Children with phenylketonuria (PKU) are treated with semisynthetic diets restricted in phenylalanine (PHE). The formulae must supply those trace elements and vitamins that are usually supplied by whole protein foods. We studied the effects of phenylalaline restricted diets in 42 children with PKU (P) and 31 normal (N) children, aged 1-12 y, divided into two groups (below and above 7 y). Plasma zinc and copper were analyzed by means of atomic spectrophotometry, and superoxide dismutase (CuZnSOD) activity was measured in erythrocytes, through NBT inhibition and its profile, as determined by isoelectric focalization. Plasma zinc of PKU children > or = 7 years old was significantly lower than that in the control group (17 mumol/L versus 20 mumol/L) but still within the normal range; in children < 7 years no substantial differences were found between the two groups. Plasma copper was not statistically different between PKU and normal children. Qualitative activity of CuZnSOD presented the same electrophoretic profile in both normal and PKU. Quantitative activity was not different in both P (1210 U/g Hb < 7 versus 1328 U/g hemoglobin (Hb) > or = 7) and N (1675 U/g Hb < 7 versus 1367 U/g Hb > or = 7). We concluded that children with PKU presented normal mean levels of zinc and copper, with preserved function, measured by enzyme activity.     

Red cell superoxide dismutase activity as an index of human copper nutrition

Red cell superoxide dismutase (SOD) activity was evaluated as a biochemical index of copper nutrition in a double-blind study of 17 infants recovering from malnutrition and receiving marginal copper intakes. Children were paired on admission by sex, birth weight, nutritional status and antecedents of diarrhea and breast feeding. Nine served as controls receiving a copper sulfate supplement (80 micrograms/kg daily for 120 d; eight received a placebo and were supplemented only if plasma copper levels dropped below 90 micrograms/dl or on d 90 for at least 30 d. After copper supplementation there was a significant rise (paired t-test; P less than 0.05) in plasma copper (96 vs. 165 micrograms/dl); ceruloplasmin (33 vs. 50 mg/dl) and SOD (1073 vs. 1371 U/g Hb). After supplementation these values were similar to those of the controls. SOD was correlated with plasma copper (r = 0.78; P less than 0.001) and not with weight-for-age or weight-for-length. Addition of copper in vitro did not modify the SOD activity. Red cell SOD is a good marker of copper nutrition in humans and correlates well with plasma copper.     

Dietary orotic acid increases 1 ,2-diacylglycerol level and lowers superoxide dismutase activity in rat liver

The effects of the dietary addition of orotic acid were studied on lipid levels in the rat liver and serum, 1,2-diacylglycerol levels in some organs, activities of antioxidant liver enzymes (superoxide dismutase, glutathione peroxidase, and catalase), and serum enzyme activities (ornithine carbamoyltransferase and alanine aminotransferase), after feeding for 0, 7, 14, and 21 d, respectively. Rats on the orotic acid diet accumulated more liver total lipids, triacylglycerol, and phospholipids than those on the basal diet. However, the levels of serum triacylglycerol and phospholipids of those rats were markedly decreased after 7, 14, and 21 d on the diet. Dietary orotic acid increased the 1,2-diacylglycerol levels in the liver of rats fed for 14 or 21 d, but not in the ileum of small intestine, vastus lateralis muscle, and heart. The addition of orotic acid lowered the activities of liver total and Cu,Zn-superoxide dismutase after feeding for 7, 14, and 21 d. The serum ornithine carbamoyltransferase activity after 14, and 21 d and that of serum alanine aminotransferase after 7, 14, and 21 d were increased. These data suggested that the increase in the activities of serum enzymes tested may result from liver damage induced by the marked accumulation of liver lipids and possibly from the increased superoxide anion because of the decreased activities of hepatic superoxide dismutase by orotic acid feeding.     

Lysosomal stability, superoxide dismutase and zinc deficiency in regenerating rat liver

1. Lysosomal stability was slightly increased in regenerating livers from rats receiving a zinc-deficient (less than 0.5 mg/kg) diet for 10 d before surgery. 2. The activity of superoxide dismutase (EC 1.15.1.1) was significantly reduced in the same tissues. 3. The results do not support the view that increased lysosomal fragility represents a major biochemical consequence of nutritional Zn deficiency in animals.     

老年性白内障患者血清及红细胞中超氧化物歧化酶水平研究

[目的]为探讨超氧化物歧化酶(SOD)与老年性白内障(SC)的关系。[方法]应用黄嘌呤氧化酶法,对128例老年性白内障患者血清T-SOD,红细胞Cu-ZnSOD活力进行检测,并与100例健康老年人作比较。[结果]老年性白内障患者T-SOD,Cu-ZnSOD活力都明显低于正常对照组,差异有显著性(P<0.01)。[结论]超氧化物歧化酶与老年性白内障密切相关,二者的动态检测和即时纠正有助于对老年性白内障预防与延缓病程。     

Rapid alteration in rat red blood cell copper chaperone for superoxide dismutase after marginal copper deficiency and repletion

There is increased incidence of human copper deficiency (CuD). A sensitive and reliable blood biomarker may reveal additional cases of marginal deficiency. Two experiments were designed to test the hypothesis that the copper chaperone for superoxide dismutase (CCS) would be a robust marker after marginal CuD. Experiment 1 used weanling male Sprague-Dawley rats that were offered a CuD diet for 4 weeks, and samples were evaluated after 1, 2, and 4 weeks and compared with copper-adequate (CuA) controls. Furthermore, iron-deficient rats were included for comparison after 2 weeks of depletion. Red blood cell and plasma cuproenzymes were evaluated through Western blot analysis. Superoxide dismutase (Sod1) and ceruloplasmin protein were found to be altered by both iron and CuD, whereas CCS and CCS/Sod1 ratio were found to only be altered only in CuD rats and, importantly, after only 1 week of treatment. Two weeks on CuA diet restored cuproenzyme levels to control values after 4 weeks of CuD depletion. In experiment 2, marginal CuD (CuM) rats were compared with CuA and CuD rats after 2 weeks of treatment. Superoxide dismutase, ceruloplasmin, and CCS/Sod1 abundances were lower in CuM and CuD groups compared with CuA rats, but there was no statistical difference between CuM and CuD rats. However, CCS was statistically different between all groups, and abundance highly correlated with liver copper concentration. Results suggest that red blood cell CCS may be an excellent biomarker for diagnosis of rapid and marginal CuD.     

Effects of copper supplementation on ceruloplasmin and copper-zinc superoxide dismutase in free-living rheumatoid arthritis patients.

Inflammation, an acute phase stress, alters copper (Cu) metabolism, but effects on human Cu requirements are unknown. Cu supplementation (2 mg/day, 4 weeks) increased erythrocyte Cu-zinc (Zn) superoxide dismutase (SOD) activity levels in 18 of 23 rheumatoid arthritis (RA) patients receiving gold or methotrexate (mean increase 21%). SOD values were significantly lower in RA patients than in 47 age- and sex-matched controls before, but not after supplementation. Supplementation did not significantly affect ceruloplasmin (Cp) activity or protein concentrations in either group. However, RA subjects showed significantly lower Cp activity to protein ratios compared to controls, before and after supplementation. Cu supplementation did not affect acute phase status of RA patients as evidenced by unchanged serum alpha-1-acid glycoprotein levels. In conclusion, the effects of Cu supplementation on erythrocyte SOD activities suggested a trend toward marginal Cu status in RA patients.     

Copper,zinc and superoxide dismutase levels in cord blood

Serum copper and zinc concentrations and SOD activities in the cord blood of preterm and term infants were determined. Neither the mean cord serum copper and zinc concentrations nor the cord blood SOD activities were significantly different between preterm and term infants. Cord blood SOD activities were not correlated with either serum copper or serum zinc concentrations. Cord serum copper concentrations were negatively correlated with gestational age, birth weight and head circumference.     

乙二醛对小鼠脂质过氧化物水平及SOD活性的影响

目的 测定乙二醛染毒小鼠血清及组织中脂质过氧化主要产物丙二醛(MDA)的含量和超氧化物歧化酶(SOD)活力的变化,以探讨乙二醛毒性的可能机制。方法 40只小鼠分成1个对照组和3个实验组,实验小鼠的染毒剂量分别为1．29,mmol／kg、2．58mmol／kg和5．16mmol／kg,每天腹腔注射1次,连续染毒30d。用硫代巴比妥酸(TBA)比色法测定血清及组织中MDA含量,用黄嘌呤氧化酶法测定全血及组织中SOD活性。结果 乙二醛染毒小鼠高剂量组肾脏MDA含量与对照组相比显著升高,其他各项指标与对照组相比差异均无显著性;小鼠全血、肝脏和肾脏中SOD活性变化与对照组相比差异均无显著性。结论 乙二醛能够增高小鼠肾脏MDA含量,提示有可能导致肾组织氧化损伤。     

硒对大鼠肝脏超氧阴离子和羟自由基的作用

目的 研究离体和在体染毒条件下亚硒酸钠对大鼠肝组织超氧阴离子(^*O2^-)和羟自由基(^*OH)生成的影响。方法 选用雄性Wistar大鼠。体外实验时，制备肝匀浆，在反应体系中加入亚硒酸钠使剂量分别达到2．185，8．750和35．000μmol／L。采用常规方法测定^*O2^-和^*OH。体内实验时，用0．75，1．50和3．00mg／kg的亚硒酸钠，腹腔注射染毒。采用电子自旋共振测定^*O2^ 和^*OH。结果 在体外染毒时，2．185μmol／L的亚硒酸钠对大鼠肝组织产生抗氧化应激作用，使过氧化脂质(MDA)、^*O2^ 和^*OH的生成量明显下降，但8．750和35．000μmol／L的亚硒酸钠则诱导大鼠肝组织产生明显的氧化应激，使^*O2^ 和^*OH的生成量显著升高。在体内染毒时，0．75，1．50和3．00mg／kg的亚硒酸钠均可引起大鼠肝组织^*O2^-和^*OH的产生量显著增加。结论 适宜剂量的亚硒酸钠抑制自由基生成。具有抗氧化作用，而较高剂量的亚硒酸钠则使自由基生成增多，导致明显的氧化应激。     

局部放射、加温对荷瘤小鼠肝脏MDA含量及SOD活性的影响

为探讨局部放射加温对S1 80 荷瘤小鼠肝脏组织脂质过氧化水平及抗氧化能力的影响。采用荷瘤小鼠模型,测定局部放射、加温后对照组、局部放射组、加温组、放射加温组小鼠肝脏丙二醛(MDA)含量及超氧化物歧化酶(SOD)活性。结果显示加温组及放射合并加温组肝脏组织MDA含量高于放射组及对照组(P <0 . 0 5 )。加温组及放射合并加温组肝脏组织SOD活性均显著低于放射组及对照组(P <0 .0 1)。提示局部加温可能使荷瘤小鼠肝脏产生大量自由基,使SOD活性降低,MDA含量升高。因此,脂质过氧化损伤可能是加温对机体造成损伤的机制之一。     

Effects of ascorbic acid and inflammation on ceruloplasmin activity levels in guinea pigs

The possibility that ascorbic acid exerts a postabsorptive effect on copper metabolism in guinea pigs was examined. A pair of ascorbic acid injections (20 mg/kg, ip, 18 h apart) caused a small but statistically significant increase in oxidase activity levels of ceruloplasmin, a serum copper protein. In contrast, dietary ascorbic acid deprivation for 14 days did not prevent increases in ceruloplasmin activity levels caused by turpentine-induced inflammation. The ascorbic acid deprivation did reduce weight gain and adrenal ascorbic acid contents but serum ascorbic acid concentrations were not significantly lowered. In summary, ascorbic acid can produce postabsorptive changes in copper metabolism but adequate intake of the vitamin is not necessary for inflammation-induced elevations of ceruloplasmin activity levels.     

Erythrocyte copper chaperone for superoxide dismutase is increased following marginal copper deficiency in adult and postweanling mice

A sensitive and reliable biomarker has yet to be identified for marginal copper deficiency in humans. The need for such a biomarker is critical, because increased cases of human copper deficiency evolve following bariatric surgery and other secondary factors besides diet. Four experiments were devised to induce marginal copper deficiency through copper-deficient (CuD) diets (5 wk for mice and 4 wk for rats). In Expt. 1 and 2, male postweanling mice were raised in either solid-bottom plastic cages (Expt. 1) or stainless steel hanging cages (Expt. 2) and compared. Postweanling rats (Expt. 3) and adult mice (Expt. 4) were also studied using stainless steel cages. Copper-adequate controls were fed a semipurified diet containing 9 mg Cu/kg. CuD rats exhibited the most severe changes in biomarkers due to copper limitation, including major reductions in plasma ceruloplasmin (Cp) and erythrocyte superoxide dismutase (Sod1) and augmentation in copper chaperone for Sod1 (CCS). The CuD mice in Expt. 2 were more deficient than the CuD mice in Expt. 1, likely due to coprophagia differences. In fact, the CuD mice in Expt. 1 had unaltered Sod1 or Cp levels. Importantly though, these marginally deficient mice and CuD adult mice that had no changes in Cp activity or liver copper level had robust augmentation of CCS. Erythrocyte CCS was the only consistent biomarker to change in copper deficiency for all dietary groups, suggesting that CCS may be an excellent biomarker for human confirmation of marginal copper deficiency.