Assessment of Total and Organic Mercury Levels in Blue Sharks (Prionace glauca) from the South and Southeastern Brazilian Coast

Mercury occurrence was evaluated in samples of edible muscle tissue of 27 blue sharks (Prionace glauca) caught in the Atlantic Ocean, adjacent to the south and southeastern Brazilian coast, indicating a slight increase in comparison with previous data obtained for the same studied area and being higher than those fish caught at different sites of the Atlantic Ocean. Total Hg concentrations ranged from 0.46 to 2.40 mg kg^?1 with the organic Hg fraction ranging between 0.44 and 2.37 mg kg^?1. A negative correlation between total Hg concentration in muscle tissue and blue shark size was obtained, and 40 % of samples analyzed had Hg concentrations higher than 1.0 mg kg^?1 Hg, the maximum concentration permitted in Brazilian predator fish. Data obtained showed that total Hg can be used as a reliable predictor of organic Hg in blue shark muscle because 95 to 98 % of the total Hg measured was found to be organic mercury. The wide range of Hg concentrations obtained for our set of samples can be explained by the heterogeneity of sampled population and the large size of the studied area. Given the adverse toxicological effects of Hg on animals and humans, a regular monitoring program of Hg contamination in Brazilian marine ecosystem can be recommended.     

东太平洋浅海长尾鲨母体和胚胎间痕量元素的迁移规律

大洋中上层鲨鱼多为金枪鱼渔业的兼捕渔获,因其生长缓慢、繁殖力低等生活史特征,极易被过度捕捞,90%种类资源已近危。而作为长生命周期的顶级捕食者,鲨鱼体内某些过高的痕量元素含量不利于资源恢复。本研究选取10尾东太平洋雌性浅海长尾鲨(Alopias pelagicus)及对应的18尾胚胎,测定其肌肉和肝脏中锌(Zn)、铜(Cu)、铬(Cr)、镍(Ni)、锰(Mn)、硒(Se)、钴(Co)、汞(Hg)、镉(Cd)、铅(Pb)和砷(As) 11种痕量元素,探寻浅海长尾鲨繁殖过程中母体与胚胎间痕量元素的迁移规律。结果表明: 对于必需元素,胚胎两种组织的Cr、Cu、Se和Mn含量均高于母体对应组织,而Ni和Zn含量在胚胎肌肉中较高、肝脏中较低;对于非必需元素,胚胎两种组织的As、Cd和Hg含量均低于母体对应组织。虽然Hg在母体和胚胎组织中含量均较高,但胚胎组织的Se/Hg均大于1,且其在胚胎中的值均大于母体,表明Se在胚胎中具有显著抑制Hg毒性的作用。肝脏作为鲨鱼胚胎发育的主要能量来源,其元素含量在胚胎与母体之间无显著相关性。由此推测,浅海长尾鲨可能存在特定的元素调控机制,以维持胚胎组织中元素含量的稳定。     

Exposure to tebuconazol in rice field and laboratory conditions induces oxidative stress in carp (Cyprinus carpio)

Pesticides can have an effect on the biochemical and physiological functions of living organisms. The changes seen in fish and their response to pesticides can be used as an example for vertebrate toxicity. In this study, carp fish (Cyprinus carpio) were exposed to different concentrations of tebuconazol fungicide, by rice field (31.95 μg/L) and laboratory (33.47 and 36.23 μg/L) conditional testing, during a 7 day period. Parameters such thiobarbituric acid-reactive substance levels (TBARS), protein carbonyl, catalase, glutathione S-transferase and acetylcholinesterase activities were studied, using the liver, brain and white muscle of the fish. The field experiment showed that the TBARS levels were increased in all the analyzed tissues. Similarly, the protein carbonyl of the liver and the brain AChE activity increased after 7 days. The laboratory experiment demonstrated that the TBARS levels in the liver were increased in both of the concentration tests. TBARS levels in the muscle increased only by the lowest test concentration. On the other hand, the protein carbonyl was increased only by the highest concentration. The results indicate that the tebuconazol exposure from the field and laboratory conditions directly affected the health of the fish, showing the occurrence of oxidative stress.     

Reduced muscle carnosine content in type 2, but not in type 1 diabetic patients

Carnosine is present in high concentrations in skeletal muscle where it contributes to acid buffering and functions also as a natural protector against oxidative and carbonyl stress. Animal studies have shown an anti-diabetic effect of carnosine supplementation. High carnosinase activity, the carnosine degrading enzyme in serum, is a risk factor for diabetic complications in humans. The aim of the present study was to compare the muscle carnosine concentration in diabetic subjects to the level in non-diabetics. Type 1 and 2 diabetic patients and matched healthy controls (total n=58) were included in the study. Muscle carnosine content was evaluated by proton magnetic resonance spectroscopy (3 Tesla) in soleus and gastrocnemius. Significantly lower carnosine content (-45%) in gastrocnemius muscle, but not in soleus, was shown in type 2 diabetic patients compared with controls. No differences were observed in type 1 diabetic patients. Type II diabetic patients display a reduced muscular carnosine content. A reduction in muscle carnosine concentration may be partially associated with defective mechanisms against oxidative, glycative and carbonyl stress in muscle.     

Aspects of the reproductive biology of two pelagic sharks in the eastern Atlantic Ocean

This study used data provided by the Chinese Longline Fishery Scientific Observer Programme from the tropical eastern Atlantic Ocean to estimate the reproductive parameters of the blue shark (Prionace glauca) and crocodile shark (Pseudocarcharias kamoharai). Sizes ranged from 80 to 298 cm fork length (FL) for blue sharks and from 48 to 99 cm FL for crocodile sharks. Sexual segregation was observed during different months for both sharks. The sex ratio for blue sharks was 1.38 F:1 M, and 1 F:2.79 M for crocodile sharks. The size of adult blue sharks ranged from 144 to 280 cm for males and from 174 to 298 cm for females; and that of crocodile sharks from 63 to 97 cm for males and 78–99 cm for females. The size at 50% of maturity for blue sharks was estimated at 191.7 cm FL for females and 197.5 cm FL for males, and that of crocodile sharks was assessed at 84.9 cm FL for females and 78.5 cm FL for males. Most sexually matured females were pregnant; their means were 207.2 ± 16.4 cm FL for blue sharks and 89.4 ± 4.3 cm FL for crocodile sharks. Mature sizes for both species were significantly different among months. Embryonic sizes also varied widely among months for crocodile sharks, but a slight change was recorded for those of blue sharks. The observed mean size at birth and litter size were 34.5 cm FL and 37 ± 12 for the blue sharks, and that of the crocodile sharks, 39.5 cm FL and a dominant four embryos in the uterus. Due to the observed increasing catch trend of blue sharks and the slow reproductive cycle of crocodile sharks, this study presents the need of implementing conservation measures to ensure the sustainability of both species in their habitat.     

The evaluation of the oxidative stress parameters in patients with primary angle-closure glaucoma

Objective

To clarify the presence of oxidative stress in patients with primary angle-closure glaucoma (PACG) and to investigate the relationship between oxidative stress and PACG.

Methods

Fifty patients with primary angle-closure glaucoma and fifty healthy controls of matched age and gender were included in the study prospectively. Serum samples were obtained to detect the oxidation degradation products malondialdehyde (MDA), conjugated diene (CD), 4-hydroxynonenal (4-HNE), advanced oxidation protein products (AOPP), protein carbonyl (PC), ischemia-modified albumin (IMA) and 8-hydroxydeoxyguanosin (8-OHdG).

Results

The concentration of MDA and CD in PACG patients was significantly higher than those of the control subjects (P<0.05, P<0.01). The serum 4-HNE concentrations were increased in PACG patients, but the differences with those of the healthy controls were not statistically significant. Compared to normal subjects, there was significant higher in serum AOPP and PC in PACG patients (P<0.01). PACG patients had higher levels of 8-OHdG in serum with respect to the comparative group of normal subjects (P<0.01). When plasma IMA levels in the PACG group were compared with those in the control group, significant increases in IMA were observed in the former (P<0.05).

Conclusions

Our study demonstrated that IMA is a new biomarker available for assessing oxidative stress in PCAG. Oxidative stress is an important risk factor in the development of primary angle-closure glaucoma. Increased levels of oxidative stress products may be associated with primary angle-closure glaucoma.     

Assessment of protein oxidation in women using raloxifene

Objectives. To assess the oxidative effects of raloxifene use in postmenopausal women by investigating protein carbonyl levels in the plasma. Methods. Nineteen osteoporotic postmenopausal women treated with raloxifene for 12 months were included in the study. Another seventeen postmenopausal women matched for age and postmenopausal years, without any medication were chosen as a control group. Protein carbonyl levels were determinated as oxidative stress markers by the use of Levine's method in the plasma of these women. Results. Serum protein carbonyl levels of postmenopausal women treated with raloxifene (1.27 ± 0.32 nmol/mg protein) were significantly lower than the control group (2.18 ± 0.27 nmol/mg protein) (p < 0.05). Conclusions. Oxidative stress has been found responsible for several diseases including cancer. Protein carbonyl levels, which are the products of protein oxidation, are one of the indicatives of oxidative stress. Therefore, the decline in protein carbonyl levels in this study revealed the decreasing oxidative stress. According to our results, it might be interpreted that raloxifene does not cause oxidative stress, and it may even have protective effects in long-term use.     

Metal concentrations and metallothionein metal detoxification in blue sharks,Prionace glauca L. from the Western North Atlantic Ocean

BackgroundElasmobranchs are particularly vulnerable to environmental metal contamination, accumulating these contaminants at high rates and excreting them slowly. The blue shark Prionace glauca L. is one of the most heavily fished elasmobranchs, although information regarding metal contamination and detoxification in this species is notably lacking.MethodsBlue sharks were sampled in the western North Atlantic Ocean, in offshore waters adjacent to Cape Cod, Massachusetts. Total and metallothionein-bound liver and muscle metal concentrations were determined by inductively coupled plasma mass spectrometry (ICP-MS), metallothionein detoxification and oxidative stress endpoints were determined by UV–vis spectrophotometry.ResultsMetallothionein detoxification occurred for As, Cd, Cs, Cu, Hg, Pb, Se, Ti and Zn in liver, and for As, Cd, Cs, Pb, Se, and Zn in muscle, while reduced glutathione defenses seem to be related to Co and Zn exposure.ConclusionThis is the first report for several metals (Ag, Co, non-radioactive Cs, Sb, Ti and V) for this species, which will aid in establishing baseline elemental data for biomonitoring efforts, health metrics, and conservation measures.     

Sex-Related Effects of Reproduction on Biomarkers of Oxidative Damage in Free-living Barn Swallows (Hirundo rustica)

According to life-history theory, the allocation of limiting resources to one trait has negative consequences for other traits requiring the same resource, resulting in trade-offs among life-history traits, such as reproduction and survival. In vertebrates, oxidative stress is increasingly being considered among the physiological mechanisms forming the currency of life-history trade-offs. In this study of the barn swallow (Hirundo rustica), we focus on the oxidative costs of reproduction, especially egg laying, by investigating the effects of breeding stage (pre- vs. post-laying) and progression of the season on three biomarkers of oxidative damage (OD) to plasma proteins, namely the concentration of malondialdehyde (MDA)-protein adducts and of protein thiol groups (PSH), and the protein carbonyl (PCO) content. Moreover, we investigated whether males and females differed in plasma OD levels, because the inherent sex differences in reproductive roles and physiology may originate sex-specific patterns of OD during breeding. We found that MDA-protein adduct levels were higher in the pre-laying than in the post-laying phase, that males had lower levels of MDA-modified proteins than females, and that the decline of MDA-protein adduct concentration between the pre- and the post-laying phase was more marked for females than males. In addition, MDA-protein adduct levels declined with sampling date, but only during the pre-laying phase. On the other hand, plasma PCO levels increased from the pre- to the post-laying phase in both sexes, and females had higher levels of PCO than males. PSH concentration was unaffected by breeding stage, sex or sampling date. On the whole, our findings indicate that biomarkers of protein oxidation closely track the short-term variation in breeding stage of both male and female barn swallows. Moreover, the higher protein OD levels observed among females compared to males suggest that egg laying entails oxidative costs, which might negatively affect female residual reproductive value.     

Unexpected effect of urate on hydrogen peroxide-induced oxidative damage in embryonic chicken cardiac cells

Uric acid (UA) is a potent scavenger of oxidants in most mammalian and avian species. The aim of this study was to obtain more comprehensive information regarding the relationship between different concentrations of UA and oxidative balance in chicken cardiac cells. First, oxidative damage parameters were measured in chicken cardiac cells treated with different concentrations of UA. UA concentrations within the normal physiological range had no effect, while treatment with a high level of UA, i.e. 1200?μM, increased the malondialdehyde (MDA) and protein carbonyl contents, decreased the superoxide dismutase (SOD) and catalase (CAT) activities, and had no effect on glutathione (GSH) in cardiac muscle cells. In addition, the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway was stimulated in cells treated with 1200?μM UA. Next, the role of UA in protecting cells from oxidative damage was investigated in hydrogen peroxide (H₂O₂)-damaged chicken cardiac cells. Treatment with UA within the normal physiological range reduced the increased MDA and protein carbonyl contents and SOD enzymatic activity induced by H₂O₂ exposure to some extent and inhibited reactive oxygen species (ROS) formation, presumably as a result of the Nrf2 pathway activation in H₂O₂-damaged cells. By contrast, the MDA and protein carbonyl contents were increased, SOD enzymatic activity was depressed, and the Nrf2 pathway was further down-regulated in H₂O₂-damaged cells treated with 1200?μM UA. In conclusion, the results indicated that physiological UA concentration partially alleviated oxidative stress in chicken cardiac muscle cells treated with H₂O₂. However, supraphysiological UA concentrations promoted oxidative damages directly in primary cultured chicken cardiac muscle cells and aggravated oxidative stress in H₂O₂-damaged cells.     

Mercury,cadmium, zinc and copper concentrations and stable isotope ratios of carbon and nitrogen in tiger sharks (Galeocerdo cuvier) culled off Ishigaki Island,Japan

We analyzed Hg, Cd, Zn and Cu in the liver as well as Hg and stable isotope ratios of carbon and nitrogen (δ¹³C and δ¹⁵N) in muscle from tiger sharks (Galeocerdo cuvier) in Japan. The Hg concentration in the muscle increased slightly and proportionally with increases in body length, but the Hg concentration in the liver increased markedly after maturation (exceeding 2.7 m precaudal length). The Hg concentration in the liver of mature shark was higher than that in the muscle. The Cd concentration in the liver increased with increases in body length. On the other hand, the Zn and Cu concentrations in the liver decreased during the growth stage, but thereafter increased with increased Cd burden due to growth. The marked increase in hepatic Hg in mature sharks may be explained by the continuous intake of Hg via food, slower growth and Hg–Se complex formation. High concentrations of Zn and Cu in the liver of immature sharks and concomitant increases in Zn and Cu with the Cd burden in the liver of mature sharks may be explained by the physiological requirements of Zn and Cu during the growth stage, the induction of metallothionein synthesis due to the Cd burden and the subsequent binding of these metals to metallothionein. The δ¹⁵N and δ¹³C values decreased with increases in body length, suggesting a shift from coastal feeding to pelagic feeding with shark growth. The Hg and Cd concentrations tended to be negatively correlated with the δ¹⁵N and δ¹³C values as a result of the increase in Hg and Cd accumulation due to the growth and the decreases in δ¹⁵N and δ¹³C values due to the sift of feeding area.     

Plasma protein carbonyl concentration is not enhanced by chronic intake of high-protein diets in adult rats

We tested the hypothesis of whether high dietary protein intake is linked to oxidative stress as measured by the concentration of reactive carbonyl residues in plasma proteins. Three groups of male Wistar rats ( approximately 230 g, n = 10) were fed either 15% (15C), 30% (30C), or 60% (60C) casein diets over a period of 18 weeks. For comparison, a vitamin E deficient diet (60C-E) based on diet 60C was given to an additional group to provoke oxidative stress. Concentrations of alpha-tocopherol in plasma and of reactive carbonyl residues in total plasma proteins were measured by high performance liquid chromatography using fluorescence and by diode array detection after 2,4-dinitrophenylhydrazine reaction, respectively. After 1 week the concentration of reactive carbonyl residues in plasma proteins was found to be significantly (P < 0.05) higher in the 60C and 60C-E groups ( approximately 2.7 nmol/mg protein) compared with the 15C and 30C groups ( approximately 1.7 nmol/mg protein). After 14 weeks the 15C (3.4 +/- 1.2 nmol/mg protein) and 60C-E groups (3.9 +/- 1.7 nmol/mg protein) showed a significantly increased concentration of reactive carbonyl residues in plasma protein compared with the 30C and 60C groups (2.5 +/- 1.0 nmol/mg protein; 2.6 +/- 0.8 nmol/mg protein). As expected, chronic vitamin E deficiency (60C-E) resulted in significantly decreased alpha-tocopherol concentrations (3.91 +/- 2.42 micromol/mL vs. 31.3 +/- 4.8 micromol/mL) and a higher concentration of reactive carbonyl residues in plasma proteins. These results do not support the hypothesis that a chronic intake of high-protein diets leads to oxidative stress in adult rats. However, in the non-adapted state (1 week) a high protein intake contributes to oxidative modifications of protein-bound amino acid residues.     

Biomagnification of Mercury and Selenium in Blue Shark Prionace glauca from the Pacific Ocean off Mexico

The aim of this study was to determine the biomagnification of mercury through the principal prey of the blue shark, Prionace glauca, off the western coast of Baja California Sur, Mexico, as well as the relationship between mercury and selenium in blue sharks. High levels of mercury were found in shark muscle tissues (1.39?±?1.58?μg/g wet weight); these values are above the allowed 1.0?μg/g for human consumption. The mercury to selenium molar ratio was 1:0.2. We found a low correlation between mercury bioaccumulation and shark size. Juveniles have lower concentrations of mercury than adults. Regarding the analyzed prey, the main prey of the blue shark, pelagic red crab, Pleuroncodes planipes, bioaccumulated 0.04?±?0.01?μg/g Hg wet weight, but the prey with higher bioaccumulation was the bullet fish Auxis spp. (0.20?±?0.02?μg/g wet weight). In terms of volume, the red crab P. planipes can be the prey that provides high levels of mercury to the blue shark.     

Oxidation state of tissue thiol groups and content of protein carbonyl groups in chickens with inherited muscular dystrophy.

Indirect evidence suggests that oxidative stress may play a role in the pathogenesis of inherited muscular dystrophy, but the significance and precise extent of this contribution is poorly understood. Compared with normal muscle, significantly higher contents of glutathione, glutathione disulphide, protein-glutathione mixed disulphides and protein carbonyl groups, and significantly lower contents of free protein thiol groups, were found in pectoralis major muscle of genetically dystrophic chickens (the muscle affected by this disease) at 4 weeks of age. Other tissues did not show such marked disease-related differences. Interestingly, the protein pool in normal, but not dystrophic, pectoralis major muscle was relatively less oxidized in relation to the glutathione pool as compared with other tissues studied. The mechanisms by which this unique relationship between the thiol pools is maintained remain unknown. Although the physiological consequences of the increased content of protein carbonyl groups and the altered thiol pools in dystrophic muscle are not clear, the changes evident at such a young age are consistent with the occurrence of oxidative stress and may reflect significant damage to cellular proteins in this disease.     

Primary prevention of diabetes mellitus type 2 and cardiovascular diseases using a cognitive behavior program aimed at lifestyle changes in people at risk: Design of a randomized controlled trial

Background

Insulin resistance and diabetes are associated with increased oxidative stress and impairment of cellular defence systems. Our purpose was to investigate the interaction between glucose metabolism, antioxidative capacity and heat shock protein (HSP) defence in different skeletal muscle phenotypes among middle-aged obese subjects during a long-term exercise and dietary intervention. As a sub-study of the Finnish Diabetes Prevention Study (DPS), 22 persons with impaired glucose tolerance (IGT) taking part in the intervention volunteered to give samples from the vastus lateralis muscle. Subjects were divided into two sub-groups (IGTslow and IGTfast) on the basis of their baseline myosin heavy chain profile. Glucose metabolism, oxidative stress and HSP expressions were measured before and after the 2-year intervention.

Results

Exercise training, combined with dietary counselling, increased the expression of mitochondrial chaperones HSP60 and glucose-regulated protein 75 (GRP75) in the vastus lateralis muscle in the IGTslow group and that of HSP60 in the IGTfast group. In cytoplasmic chaperones HSP72 or HSP90 no changes took place. In the IGTslow group, a significant positive correlation between the increased muscle content of HSP60 and the oxygen radical absorbing capacity values and, in the IGTfast group, between the improved VO_2max value and the increased protein expression of GRP75 were found. Serum uric acid concentrations decreased in both sub-groups and serum protein carbonyl concentrations decreased in the IGTfast group.

Conclusion

The 2-year intervention up-regulated mitochondrial HSP expressions in middle-aged subjects with impaired glucose tolerance. These improvements, however, were not correlated directly with enhanced glucose tolerance.     

Overexpression of glyoxalase-I reduces hyperglycemia-induced levels of advanced glycation end products and oxidative stress in diabetic rats

The reactive advanced glycation end product (AGE) precursor methylglyoxal (MGO) and MGO-derived AGEs are associated with diabetic vascular complications and also with an increase in oxidative stress. Glyoxalase-I (GLO-I) transgenic rats were used to explore whether overexpression of this MGO detoxifying enzyme reduces levels of AGEs and oxidative stress in a rat model of diabetes. Rats were made diabetic with streptozotocin, and after 12 weeks, plasma and multiple tissues were isolated for analysis of AGEs, carbonyl stress, and oxidative stress. GLO-I activity was significantly elevated in multiple tissues of all transgenic rats compared with wild-type (WT) littermates. Streptozotocin treatment resulted in a 5-fold increase in blood glucose concentrations irrespective of GLO-I overexpression. Levels of MGO, glyoxal, 3-deoxyglucosone, AGEs, and oxidative stress markers nitrotyrosine, malondialdehyde, and F2-isoprostane were elevated in the diabetic WT rats. In diabetic GLO-I rats, glyoxal and MGO composite scores were significantly decreased by 81%, and plasma AGEs and oxidative stress markers scores were significantly decreased by ～50%. Hyperglycemia induced a decrease in protein levels of the mitochondrial oxidative phosphorylation complex in the gastrocnemius muscle, which was accompanied by an increase in the lipid peroxidation product 4-hydroxy-2-nonenal, and this was counteracted by GLO-I overexpression. This study shows for the first time in an in vivo model of diabetes that GLO-I overexpression reduces hyperglycemia-induced levels of carbonyl stress, AGEs, and oxidative stress. The reduction of oxidative stress by GLO-I overexpression directly demonstrates the link between glycation and oxidative stress.     

Nifedipine decreases sVCAM-1 concentrations and oxidative stress in systemic sclerosis but does not affect the concentrations of vascular endothelial growth factor or its soluble receptor 1

Microvascular injury, oxidative stress, and impaired angiogenesis are prominent features of systemic sclerosis (SSc). We compared serum markers of these phenomena at baseline and after treatment with nifedipine in SSc patients. Forty successive SSc patients were compared with 20 matched healthy subjects. All SSc patients stopped taking calcium-channel blockers 72 hours before measurements. Twenty SSc patients were also examined after 14 days of treatment with nifedipine (60 mg/day). Quantitative ELISA was used to measure the serum concentrations of vascular endothelial growth factor (VEGF), soluble VEGF receptor 1 (sVEGFR-1), soluble vascular cell adhesion molecule 1 (sVCAM-1), carbonyl residues, and advanced oxidation protein products (AOPP). The median concentrations of VEGF, sVEGFR-1, sVCAM-1, carbonyl residues, and AOPP were significantly higher in SSc patients than in healthy subjects at baseline. A correlation was found between VEGF concentration and carbonyl residue concentration (r = 0.43; P = 0.007). Nifedipine treatment led to a significant decrease in concentrations of sVCAM-1, carbonyl residues, and AOPP but did not affect concentrations of VEGF and sVEGFR-1. Nifedipine treatment ameliorated endothelium injury in patients with SSc, as shown by the concentrations of adhesion molecules and oxidative damage markers. The fact that VEGF and sVEGFR-1 concentrations were not changed whereas oxidative stress was ameliorated by nifedipine is consistent with the hypothesis that VEGF signalling is impaired in SSc. However, more experimental evidence is needed to determine whether the VEGF pathway is intrinsically defective in SSc.     

HSP70 and other possible heat shock or oxidative stress proteins are induced in skeletal muscle, heart, and liver during exercise

Exercise causes heat shock (muscle temperatures of up to 45 degrees C, core temperatures of up to 44 degrees C) and oxidative stress (generation of O2- and H2O2), and exercise training promotes mitochondrial biogenesis (2-3-fold increases in muscle mitochondria). The concentrations of at least 15 possible heat shock or oxidative stress proteins (including one with a molecular weight of 70 kDa) were increased, in skeletal muscle, heart, and liver, by exercise. Soleus, plantaris, and extensor digitorum longus (EDL) muscles exhibited differential protein synthetic responses ([3H]leucine incorporation) to heat shock and oxidative stress in vitro but five proteins (particularly a 70 kDa protein and a 106 kDa protein) were common to both stresses. HSP70 mRNA levels were next analyzed by Northern transfer, using a [32P]-labeled HSP70 cDNA probe. HSP70 mRNA levels were increased, in skeletal and cardiac muscle, by exercise and by both heat shock and oxidative stress. Skeletal muscle HSP70 mRNA levels peaked 30-60 min following exercise, and appeared to decline slowly towards control levels by 6 h postexercise. Two distinct HSP70 mRNA species were observed in cardiac muscle; a 2.3 kb mRNA which returned to control levels within 2-3 h postexercise, and a 3.5 kb mRNA species which remained at elevated concentrations for some 6 h postexercise. The induction of HSP70 appears to be a physiological response to the heat shock and oxidative stress of exercise. Exercise hyperthermia may actually cause oxidative stress since we also found that muscle mitochondria undergo progressive uncoupling and increased O2- generation with increasing temperatures.(ABSTRACT TRUNCATED AT 250 WORDS)     

Association between Exposure to Environmental Tobacco Smoke and Biomarkers of Oxidative Stress Among Patients Hospitalised with Acute Myocardial Infarction

Objective

To determine whether exposure to environmental tobacco smoke was associated with oxidative stress among patients hospitalised for acute myocardial infarction.

Design

An existing cohort study of 1,261 patients hospitalised for acute myocardial infarction.

Setting

Nine acute hospitals in Scotland.

Participants

Sixty never smokers who had been exposed to environmental tobacco smoke (admission serum cotinine ≥3.0 ng/mL) were compared with 60 never smokers who had not (admission serum cotinine ≤0.1 ng/mL).

Intervention

None.

Main outcome measures

Three biomarkers of oxidative stress (protein carbonyl, malondialdehyde (MDA) and oxidised low-density lipoprotein (ox-LDL)) were measured on admission blood samples and adjusted for potential confounders.

Results

After adjusting for baseline differences in age, sex and socioeconomic status, exposure to environmental tobacco smoke was associated with serum concentrations of both protein carbonyl (beta coefficient 7.96, 95% CI 0.76, 15.17, p = 0.031) and MDA (beta coefficient 10.57, 95% CI 4.32, 16.81, p = 0.001) but not ox-LDL (beta coefficient 2.14, 95% CI −8.94, 13.21, p = 0.703).

Conclusions

Exposure to environmental tobacco smoke was associated with increased oxidative stress. Further studies are requires to explore the role of oxidative stress in the association between environmental tobacco smoke and myocardial infarction.     

Chronically and acutely exercised rats: biomarkers of oxidative stress and endogenous antioxidants.

The responses to oxidative stress induced by chronic exercise (8-wk treadmill running) or acute exercise (treadmill running to exhaustion) were investigated in the brain, liver, heart, kidney, and muscles of rats. Various biomarkers of oxidative stress were measured, namely, lipid peroxidation [malondialdehyde (MDA)], protein oxidation (protein carbonyl levels and glutamine synthetase activity), oxidative DNA damage (8-hydroxy-2'-deoxyguanosine), and endogenous antioxidants (ascorbic acid, alpha-tocopherol, glutathione, ubiquinone, ubiquinol, and cysteine). The predominant changes are in MDA, ascorbic acid, glutathione, cysteine, and cystine. The mitochondrial fraction of brain and liver showed oxidative changes as assayed by MDA similar to those of the tissue homogenate. Our results show that the responses of the brain to oxidative stress by acute or chronic exercise are quite different from those in the liver, heart, fast muscle, and slow muscle; oxidative stress by acute or chronic exercise elicits different responses depending on the organ tissue type and its endogenous antioxidant levels.