Antioxidant status and biomarkers of oxidative stress in dogs with congestive heart failure

Alterations in antioxidant status and oxidative stress have been documented in dogs with dilated cardiomyopathy (DCM). The purpose of this study was to more broadly assess this relationship in dogs with congestive heart failure (CHF). Malondialdehyde (MDA), 8-F(2alpha)-isoprostane, protein carbonyls, reduced (GSH) and oxidized (GSSG) glutathione, vitamins A, C, and E, and oxygen radical absorbance capacity (ORAC) were measured from a single venous blood sample from dogs with CHF secondary to DCM or chronic valvular disease (CVD) and in healthy controls. Nineteen dogs with CHF (14 CVD and 5 DCM) and 12 healthy controls were enrolled in the study. Concentrations of 8-F(2alpha)-isoprostane (CHF: 44.6 pg/mL [range, 27.1-98.0 pg/mL], controls: 25.3 pg/ mL [range, 11.1-80.4 pg/mL]) but not MDA (CHF: 4.11 microM [range, 1.89-6.39 microM], controls: 3.88 microM [range, 2.14-4.72 microM]) or protein carbonyls (0.69 nmol/mg protein [range, 0.37-1.67 nmol/mg protein], controls: 0.80 nmol/mg protein [range, 0.40-1.14 nmol/mg protein]) were significantly higher in the dogs with CHF than in the controls. Vitamin E concentration (CHF: 2,215 microg/ dL [range, 916-3,499 microg/dL], controls: 2,820 microg/dL [range, 1,738-3,775 microg/dL]) and GSH:GSSG (CHF: 12.0 [range, 3.69-30.1], controls: 22.7 [range, 12.5-227]) were significantly lower, whereas ORAC (CHF: 824 micromol Trolox equivalent/L [range, 304-984], controls: 497 micromol Trolox equivalent/L [range, 258-759]) and vitamin C (CHF: 0.90 mg/dL [range, 0.55-2.02 mg/dL], controls: 0.72 mg/dL [range, 0.43-0.85 mg/dL]) concentrations were higher in dogs with CHF than in controls. Vitamin A concentrations were not different between dogs with CHF and controls. No differences in any of the parameters were detected between dogs with DCM versus those with CVD. Some antioxidant defenses are decreased in dogs with CHF, and some biomarkers of oxidative stress are increased in dogs with CHF. The effect of dietary interventions to correct this imbalance in antioxidant defenses warrants further study.     

Effect of propofol on oxidative stress status in erythrocytes from dogs under general anaesthesia

Background

Alterations of the normal redox balance might be attributed to increase of plasma free-radical concentration and a disruption of the antioxidant defense system. One of the adverse effects of general anaesthetics is the exogen sources of reactive oxygen radicals that are responsible for several diseases. The purposes of the current study were to evaluate the effect of propofol on oxidative stress and to compare the differences between propofol induction only and induction plus continuous infusion on antioxidant status in dogs.

Findings

Beagle dogs were evaluated in the present study. The dogs were assigned randomly to receive three treatments in a crossover model. The three treatments were: group 1 (n = 9), 2% isoflurane; group 2 (n = 9), anaesthesia induced with an intravenous (IV) bolus dose of 6 mg/kg propofol and maintained with 1.5–2% isoflurane; group 3 (n = 9), total IV anaesthesia (induction with 6 mg/kg propofol, infusion with 0.6 mg/kg/min propofol). The results of this study show that dogs exposed to isoflurane had decreased antioxidant enzymes activities, whereas dogs injected with propofol had increased antioxidant enzymes activities.

Conclusions

The results of this study showed that an infusion dose of propofol has antioxidant effects in dogs. These effects may be beneficial to patients in whom free radicals play a role in oxidative stress, such as those with ischemia. Further studies are needed to evaluate whether these antioxidant effects of the anaesthetic are of clinical value.     

Effects of Selenium Administration on Erythrocyte and Blood Plasma Glutathione Peroxidase Activity in Goats

The activity of glutathione peroxidase (GSH-Px, E.G. 1.11.1.9.) was determined in heparinized whole blood, blood plasma and washed erythrocytes from goats before and up to 4 weeks after the administration of selenium (0.4 mg/10 kg BW) and vitamin E (20 mg/10 kg BW) or only vit. E (20 mg/10 kg BW). It was found that Se administration caused a significant increase in enzyme activity in whole blood and washed erythrocytes first detected 2 weeks after the intramuscular injection of Se. No changes were observed in plasma from the treated animals. Minor and insignificant changes were seen in the vit. E treated control animals. It is concluded that GSH-Px activity in blood plasma or serum is of no value as a short-term indicator of the selenium status of goats but whole blood is a good indicator of the long-term status.     

redox status evaluation in dogs affected by mast cell tumour

Oxidative stress status has been evaluated in depth in human medicine and its role in carcinogenesis has been clearly established. The purpose of this prospective study was to evaluate antioxidant concentrations and oxidative stress in dogs with mast cell tumours (MCTs) that had received no previous treatments, and to compare them to healthy controls. In 23 dogs with mast cell tumour and 10 healthy controls, oxidative status was assessed using the Reactive Oxygen Metabolites‐derived compounds (d‐ROMs) test, antioxidant activity was measured by the Biological Antioxidant Potential (BAP) test, and α‐tocopherol levels were evaluated using high‐performance liquid chromatography and ultraviolet analysis. At baseline, dogs with MCT had significantly higher d‐ROMs (P < 0.00001) and lower BAP (P < 0.0002) compared with healthy controls. However, no significant difference was observed for α‐tocopherol (P = 0.95). Results suggest that oxidative stress pattern and oxidative defence barrier are altered in dogs with newly diagnosed MCT compared with control dogs. Future studies are needed in order to assess the prognostic role of oxidative stress and to evaluate the impact of different therapeutic approaches.     

Protecting effect of vitamin E supplementation on submaximal exercise-induced oxidative stress in sedentary dogs as assessed by erythrocyte membrane fluidity and paraoxonase-1 activity

The aim of this placebo-controlled study was to investigate the effects of oral vitamin E supplementation for 10 weeks on exercise-induced oxidative damage in untrained dogs. Eight dogs were randomly assigned to a supplementation (n = 4) or control (n = 4) group and underwent two isolated submaximal exercise sessions, 10 weeks apart. Blood was collected during each session to measure erythrocyte membrane fluidity (EMF), paraoxonase-1 (PON1) activity, plasma malondialdehyde (MDA) and vitamin E concentrations. These biomarkers were measured in venous blood samples collected before (t₀), just after (t, EMF only) and 1 d (t + 1 d) and 7 d (t + 7 d) after the dogs ran on a treadmill.Prior to vitamin E supplementation, exercise induced a significant decrease in PON1 activity, EMF, vitamin E concentration and a significant increase in MDA concentration at t + 1 d. After a 10 week vitamin E supplementation period, these exercise-induced changes in PON1 activity, EMF and MDA concentration were still significant in the control group, but not in the supplemented group. These results suggested that vitamin E supplementation had a protective effect on submaximal exercise-induced oxidative damage in sedentary dogs.     

维生素E防治肉鸡热应激机理的初步研究

将１２０只ＡＡ肉鸡饲养于高温（２７℃～３５℃）、高湿（８３％～９０％）环境中,检测３０,５０日龄血液生化及内分泌指标的变化,以研究维生素Ｅ（ＶＥ）防治肉鸡热应激的机理。结果表明,补给ＶＥ后肉鸡血清甲状腺激素、总蛋白、白蛋白、钾、钙、磷含量及乳酸脱氢酶活性显著增加,血清尿素氮、氯及肌酸磷酸激酶活性、血清皮质醇含量显著下降,但对血清钠和血糖含量影响不大。由此可见,ＶＥ防治肉鸡热应激的机理可归因于ＶＥ对肉鸡内分泌功能、蛋白质及糖代谢、电解质及酸碱平衡的调节作用。     

Radiographic assessment of liver volume in dogs

In a group of 65 dogs, radiographic liver length, the length of the axis from the most cranial part of the diaphragm to the apex of the liver tip, was correlated significantly (P less than 0.000001) with real liver volume. Within this group, radiographic liver length, compared with the length of the eleventh thoracic vertebra, was correlated with liver volume per kilogram of body weight. In a group of 30 dogs, with histologically normal liver, this measurement was not affected by thoracic conformation. These findings suggest that radiographic liver length is a reliable measurement for estimating liver volume in dogs and that it is not influenced by thoracic conformation. For 60 of the 65 dogs, a method of assessment of liver volume was formulated that required 2 measurements to be made on the lateral abdominal radiograph and 1 to be made on the dog itself.     

Evaluation of oxidative stress in hunting dogs during exercise

Exercise has been shown to increase the production of reactive oxygen species (ROS) to a point that can exceed antioxidant defenses, to cause oxidative stress. The aim of our trials was to evaluate oxidative stress and recovery times in trained dogs during two different hunting exercises, with reactive oxygen metabolites-derivatives (d-ROMs) and biological antioxidant potential (BAP) tests. A group of nine privately owned Italian hounds were included. A 20-min aerobic exercise and a 4-h aerobic exercise, after 30 days of rest, were performed by the dogs. Our results show an oxidative stress after exercise due to both the high concentration of oxidants (d-ROMs) and the low level of antioxidant power (BAP). Besides, the recovery time is faster after the 4-h aerobic exercise than the 20-min aerobic exercise. Oxidative stress monitoring during dogs exercise could become an interesting aid to establish ideal adaptation to training.     

Serial determination of biomarkers of oxidative stress and antioxidant status in dogs with naturally occurring gastric dilatation-volvulus

Objective: To serially determine the biomarkers of oxidative stress and antioxidant status of dogs with gastric dilatation‐volvulus (GDV) over 48 hours. Design: Prospective study. Setting: Veterinary teaching hospital intensive care unit. Animals: Thirteen client‐owned dogs with GDV. Interventions: None. Measurement and main results: For all dogs, biomarkers of oxidative stress and antioxidant status were ascertained. Indicators of oxidative stress measured included F_2α‐isoprostanes (isoprostanes) and malondialdehyde (MDA). Vitamin C, vitamin E, glutathione peroxidase (GSHPx), and oxygen radical absorbance capacity (ORAC) were measured to assess antioxidant status. Oxidants and antioxidants were measured at the time of admission and at 24 and 48 hours post‐admission. There were significant decreases in vitamin E (P=0.002), vitamin C (P=0.001), ORAC (P=0.02), and MDA (P=0.001) during hospitalization. There was no significant change in GSHPx and isoprostane concentrations over time. Conclusion: Oxidative stress and antioxidant capacity in dogs with GDV change over time. Further studies measuring oxidative stress in more severely affected dogs and performing measurements earlier in the disease process may be beneficial in determining when oxidative stress is most severe during the course of GDV management.     

Serum bile acids as an indicator of liver disease in dogs

Total serum bile acids were determined in 62 dogs with different primary or secondary liver diseases, using 3α-hydroxysteroid dehydrogenase coupled to nitrobluetetrazolium in a centrifugal analyzer. A reaction time of 4 min was sufficient, yielding a within run coefficient of variation of 7% at 6 µmol/1 and 3% at 27 µmol/1. A reference range of 0–4.4 µmol/1 2 h post prandially was observed. The sensitivity of bile acids as a liver function test was superior to that of alanine and aspartate aminotransferase, alkaline phosphatase, γ-glutamyltransferase and combinations of two of these. The bile acids test detected 36 of 39 patients with a morphological or clinical liver diagnosis. For dogs with heart failure the bile acids test was a markedly more sensitive indicator of secondary liver involvement than alanine aminotransferase or alkaline phosphatase. For secondary liver affections associated with pyometra or epilepsy medication the opposite was the case. Bile acid values in the pooled patient material was not correlated to any of the 4 enzymes measured. For cirrhosis there was positive correlation, however, with the amino transferase values.     

Antioxidant compounds and oxidative stress in female dogs during pregnancy

Pregnancy is a physiological period during which different metabolic pathways are altered, resulting in greater oxygen consumption and modifications of the consumption of energy substrates, with a consequent greater exposure to oxidative stress. The objective of the present study was to determine and describe the serum profile of some antioxidant biomarkers and of oxidative stress markers during pregnancy in healthy dogs. Twenty nonpregnant (NP) and 20 pregnant (P) female dogs were studied. Serum samples were obtained from the animals during the 1st, 3rd, 5th and 7th weeks of pregnancy or during diestrus for the dosage of antioxidant molecules (vitamin E, vitamin A, zinc and magnesium) and oxidative stress markers (TBARS and carbonyl protein). The results revealed a statistically significant difference (p<0.05) between the P and NP groups during the 3rd and 5th week for vitamins A and E (NP>P), and between the 1st and 3rd week for magnesium (NP>P). The other parameters did not differ between weeks within the same group or between groups. The present study shows that the levels of antioxidant molecules of pregnant dogs differed from that of nonpregnant dogs. These mechanisms may represent a protection against oxidative stress during this period for this species, a fact that definitely deserves further study. Also, the participation of other protective mechanisms and the interference of the fetal-placental unit with oxidative stress are still unknown.     

Blood and milk status of vitamin E,vitamin A,and selenium in nursing Awassi ewes injected with vitamin E and selenium

Abstract

This study investigated the effects of vitamin E and selenium (Se) injections on concentrations of vitamin E, vitamin A, and Se in blood and milk to predict when injections may improve ewes’ performance. Awassi ewes received 0 (control, 13 ewes) or 15 plus 0.05?mg/kg BW of vitamin E and Se (injected, 15 ewes) at 1 and 4 weeks postpartum. Blood and milk samples were collected weekly for 6 weeks. Injections increased vitamin E, decreased Se, and had no effects on vitamin A levels in blood. Blood vitamin E was correlated positively with vitamin A. Injections increased vitamin E, but had no effects on vitamin A or Se levels in milk. Milk vitamin A was positively correlated with vitamin E and Se levels in the control group. Milk vitamins E and A were positively correlated with their corresponding levels in blood. Milk somatic cell count was negatively correlated with blood vitamin A levels.     

犬电视辅助胸腔镜手术(VATS)和开胸肺切除术对氧化应激的影响

14只健康犬随机分为电视辅助胸腔镜手术(video-assisted thoracoscopic surgery,VATS)组和开胸组,每组7只,2组动物分别采用VATS方法和开胸方法进行单侧全肺切除术。通过检测在术前、术中及术后不同时间点的血清MDA、SOD、GSH-Px、TNOS和iNOS含量变化,比较VATS和开胸手术对机体氧化应激的影响。结果显示:与术前相比,在术后4h2组各应激水平变化值达到最大,并且差异显著(P0.05);GSH-Px和iNOS的检测结果显示VATS组更早出现显著性差异变化(2h)。在开胸手术中各项指标的峰值较高。说明2种手术方法均能够引起机体强烈的氧化应激;VATS手术产生相对低的应激水平,但是可能会更早出现应激状态。     

Effect of dietary antioxidant supplementation on the oxidative status of plasma in broilers

In this study, the effect of dietary antioxidants on the plasma oxidative status of growing birds fed a diet rich in polyunsaturated fatty acids was investigated. One‐day‐old broilers were fed for 42 days a diet containing 4% linseed oil and supplemented with single plant extracts rich in antioxidants (natural tocopherols, rosemary, grape seed, green tea, tomato) or a combination of some of these plant extracts, in two different total doses (100 and 200 mg product/kg feed). A diet with synthetic antioxidants with and without α‐tocopheryl acetate (200 mg/kg feed) were also included. The plasma oxidative status was evaluated measuring the ferric reducing ability of plasma (FRAP), the superoxide dismutase (SOD) and glutathione peroxidase (GSH‐Px) activity. Lipid peroxidation was measured by thiobarbituric acid‐reactive substances (TBARS). No significant effect of the dietary treatments was observed for FRAP as well as for TBARS. However, diet affected GSH‐Px activity (p = 0.002) and a trend for an effect on SOD activity was observed (p = 0.084). A higher GSH‐Px activity was found for 200 mg/kg tomato extract and natural α‐tocopherol in relation to the corresponding 100 mg/kg treatment, and the lowest GSH‐Px activity was measured for the synthetic antioxidants treatment. The lowest and highest SOD activity were found for the 200. and 100 mg/kg treatment with tomato extract respectively. In conclusion, the oxidative status and lipid oxidation of plasma in broilers was not affected by feeding natural antioxidant extracts at the doses in the present study, but some changes in antioxidant enzyme activities were observed, of which the implication remains to be elucidated.     

Dietary inclusion of tomato pomace improves meat oxidative stability of young pigs

The aim of this study was to assess the nutritional effect of tomato pomace, in combination with two distinct fat sources (lard or soya bean oil), on longissimus lumborum muscle, subcutaneous fat and liver of young pigs. Forty male pigs of 4 weeks old were randomly assigned to four dietary treatments using two fibre sources (wheat bran or 5.0% tomato pomace) and two fat sources (lard or soya bean oil), in a 2 × 2 factorial design for a 5‐week trial. Tomato pomace did not improve colour, fatty acid profile, cholesterol content or lipid oxidation, nor did it yield detectable levels in lycopene or β‐carotene in the meat (p > 0.05). However, a positive increase in α‐tocopherol content of meat and liver was observed in pigs fed tomato pomace (p < 0.05). Compared with lard, soya bean oil increased MUFA and PUFA proportions and decreased the percentage of SFA (p < 0.05). Our results indicate that 5.0% of tomato pomace increases pork oxidative stability and that 5.0% of soya bean oil, compared with lard, improves its nutritional quality.