Exogenously-Sourced Ethylene Positively Modulates Photosynthesis, Carbohydrate Metabolism, and Antioxidant Defense to Enhance Heat Tolerance in Rice

The effect of exogenously-applied ethylene sourced from ethephon (2-chloroethyl phosphonic acid)was studied on photosynthesis, carbohydrate metabolism, and high-temperature stress tolerance in Taipei-309 and Rasi cultivars of rice (Oryza sativa L.). Heat stress increased the content of H₂O₂ and thiobarbituric acid reactive substances (TBARS)more in Rasi than Taipei-309. Further, a significant decline in sucrose, starch, and carbohydrate metabolism enzyme activity and photosynthesis was also observed in response to heat stress. The application of ethephon reduced H₂O₂ and TBARS content by enhancing the enzymatic antioxidant defense system and improved carbohydrate metabolism, photosynthesis, and growth more conspicuously in Taipei-309 under heat stress. The ethephon application enhanced photosynthesis by up-regulating the psbA and psbB genes of photosystem II in heat-stressed plants. Interestingly, foliar application of ethephoneffectively down-regulated high-temperature-stress-induced elevated ethylene biosynthesis gene expression. Overall, ethephon application optimized ethylene levels under high-temperature stress to regulate the antioxidant enzymatic system and carbohydrate metabolism, reducing the adverse effects on photosynthesis. These findings suggest that ethylene regulates photosynthesis via carbohydrate metabolism and the antioxidant system, thereby influencing high-temperature stress tolerance in rice.

Impact of the antioxidant quercetin on morphological integrity and follicular development in the in vitro culture of Bos indicus female ovarian fragments

We evaluated the effect of quercetin on the in vitro culture of bovine ovarian fragments in relation to morphology, development, and oxidative stress. Ovaries (n = 12) from Nelore heifers (n = 6) were used. Each pair of ovaries was divided into nine fragments, and one fragment from each animal was fixed in Bouin solution for 24 h (histology control) or frozen (- 80°C; control for oxidative stress). Other ovarian fragments (n = 8) were distributed into concentrations of 0, 10, 25, and 50 μg/mL of quercetin added to the culture medium for 5 or 10 d. Data were analyzed by chi-square test or ANOVA followed by Tukey's test (P < 0.05). Treatment with 25 μg/mL quercetin resulted in the highest proportion of total intact follicles for 5 (67.3%) and 10 d (57.1%); the concentration of 25 μg/mL also presented the best proportion of developing follicles for 5 d (68.7%) and 10 d (62.8%). Treatment with 25 μg/mL quercetin resulted in significant ferric reduction for 10 d of culture, but not for 5 d. No difference (P > 0.1) was observed in the production of reactive oxygen species or in the oxidative degradation of lipids between treatments and non-cultivated controls. Treatment with 25 μg/mL quercetin preserved the morphological integrity of the developing follicles for 5 and 10 d of culture, in addition to promoting the best antioxidant potential after 10 d of culture in bovine ovarian fragments.

Poaceae Type II Galactinol Synthase 2 from Antarctic Flowering Plant Deschampsia antarctica and Rice Improves Cold and Drought Tolerance by Accumulation of Raffinose Family Oligosaccharides in Transgenic Rice Plants

Deschampsia antarctica is a Poaceae grass that has adapted to and colonized Antarctica. When D. antarctica plants were subjected to cold and dehydration stress both in the Antarctic field and in laboratory experiments, galactinol, a precursor of raffinose family oligosaccharides (RFOs) and raffinose were highly accumulated, which was accompanied by upregulation of galactinol synthase (GolS). The Poaceae monocots have a small family of GolS genes, which are divided into two distinct groups called types I and II. Type II GolSs are highly expanded in cold-adapted monocot plants. Transgenic rice plants, in which type II D. antarctica GolS2 (DaGolS2) and rice GolS2 (OsGolS2) were constitutively expressed, were markedly tolerant to cold and drought stress as compared to the wild-type rice plants. The RFO contents and GolS enzyme activities were higher in the DaGolS2- and OsGolS2-overexpressing progeny than in the wild-type plants under both normal and stress conditions. DaGolS2 and OsGolS2 overexpressors contained reduced levels of reactive oxygen species (ROS) relative to the wild-type plants after cold and drought treatments. Overall, these results suggest that Poaceae type II GolS2s play a conserved role in D. antarctica and rice in response to drought and cold stress by inducing the accumulation of RFO and decreasing ROS levels.

Effects of Redox Disturbances on Intestinal Contractile Reactivity in Rats Fed with a Hypercaloric Diet

Few studies have associated the effects of changes in caloric intake and redox disturbances in the gastrointestinal tract. Therefore, the present study aimed at evaluating the hypercaloric diet consumption influence on the contractile reactivity of intestinal smooth muscle, morphology, and oxidative stress of rat ileum. Wistar rats were randomly divided into groups that received a standard diet and fed with a hypercaloric diet for 8 weeks. Animals were euthanized, and the ileum was isolated to isotonic contraction monitoring. Morphology was evaluated by histological staining and oxidative stress by quantification of malondialdehyde levels and total antioxidant activity. Cumulative concentration-response curves to KCl and carbachol were attenuated in rats fed with a hypercaloric diet compared to those that received a standard diet. In addition, an increase in caloric intake promotes a rise in the thickness of the longitudinal smooth muscle layer of rat ileum and tissue malondialdehyde levels, characterizing lipid peroxidation, as well as a decrease in the antioxidant activity. Thus, it was concluded that the consumption of a hypercaloric diet impairs rat intestinal contractility due to mechanisms involving modifications in the intestinal smooth muscle architecture triggered by redox disturbances.

Cultivar and Metal-Specific Effects of Endophytic Bacteria in Helianthus tuberosus Exposed to Cd and Zn

Plant growth promoting endophytic bacteria (PGPB) isolated from Brassica napus were inoculated in two cultivars of Helianthus tuberosus (VR and D19) growing on sand supplemented with 0.1 mM Cd or 1 mM Zn. Plant growth, concentrations of metals and thiobarbituric acid (TBA) reactive compounds were determined. Colonization of roots of H. tuberosus D19 by Pseudomonas sp. 262 was evaluated using confocal laser scanning microscopy. Pseudomonas sp. 228, Serratia sp. 246 and Pseudomonas sp. 262 significantly enhanced growth of H. tuberosus D19 exposed to Cd or Zn. Pseudomonas sp. 228 significantly increased Cd concentrations in roots. Serratia sp. 246, and Pseudomonas sp. 256 and 228 resulted in significantly decreased contents of TBA reactive compounds in roots of Zn exposed D19 plants. Growth improvement and decrease of metal-induced stress were more pronounced in D19 than in VR. Pseudomonas sp. 262-green fluorescent protein (GFP) colonized the root epidermis/exodermis and also inside root hairs, indicating that an endophytic interaction was established. H. tuberosus D19 inoculated with Pseudomonas sp. 228, Serratia sp. 246 and Pseudomonas sp. 262 holds promise for sustainable biomass production in combination with phytoremediation on Cd and Zn contaminated soils.

Hepatic oxidative stress and metal subcellular partitioning are affected by selenium exposure in wild yellow perch (Perca flavescens)

Yellow perch (Perca flavescens) collected from 11 lakes in the Canadian mining regions of Sudbury (Ontario) and Rouyn-Noranda (Quebec) display wide ranges in the concentrations of cadmium (Cd), nickel (Ni), selenium (Se), and thallium (Tl) in their livers. To determine if these trace elements, as well as copper (Cu) and zinc (Zn), are causing oxidative stress in these fish, we measured three biochemical indicators (glutathione (GSH), glutathione disulfide (GSSG) and thiobarbituric acid-reactive substances (TBARS)) in their livers. We observed that 44% of the yellow perch that we collected were at risk of cellular oxidative stress and lipid peroxidation. Considering all fish from all lakes, higher liver Se concentrations were coincident with both lower proportions of GSSG compared to GSH and lower concentrations of TBARS, suggesting that the essential trace-element Se acts as an antioxidant. Furthermore, fish suffering oxidative stress had higher proportions of Cd, Cu and Zn in potentially sensitive subcellular fractions (organelles and heat-denatured proteins) than did fish not suffering from stress. This result suggests that reactive oxygen species may oxidize metal-binding proteins and thereby reduce the capacity of fish to safely bind trace metals. High Cd concentrations in metal-sensitive subcellular fractions likely further exacerbate the negative effects of lower Se exposure.

pH-Insensitive FRET Voltage Dyes

Many high-throughput ion channel assays require the use of voltage-sensitive dyes to detect channel activity in the presence of test compounds. Dye systems employing Förster resonance energy transfer (FRET) between 2 membrane-bound dyes are advantageous in combining high sensitivity, relatively fast response, and ratiometric output. The most widely used FRET voltage dye system employs a coumarin fluorescence donor whose excitation spectrum is pH dependent. The authors have validated a new class of voltage-sensitive FRET donors based on a pyrene moiety. These dyes are significantly brighter than CC2-DMPE and are not pH sensitive in the physiological range. With the new dye system, the authors demonstrate a new high-throughput assay for the acid-sensing ion channel (ASIC) family. They also introduce a novel method for absolute calibration of voltage-sensitive dyes, simultaneously determining the resting membrane potential of a cell. ( Journal of Biomolecular Screening 2007:656-667)

Storage and Microwave Reheating Effects on Lipid Oxidation of Roast Beef1

Sensory analysis and thiobarbituric acid (TBA) tests were conducted on beef (Longissimus muscle) which had been roasted in a conventional electric oven at 163 degrees C (325 degrees F), sliced and stored in either a vacuum package or in a casserole at 4 degrees C (40 degrees F), for two or for seven days, and then reheated in a conventional or in a microwave oven. Methods of reheating, microwave or conventional oven, did not influence sensory scores for warmed-over aroma or flavor or TBA values. Method of packaging influenced both sensory scores and TBA values whereas length of storage affected only TBA values.

Oxidative stress and the enzyme system of aldehyde catabolism in the muscle mitochondria of immobilized pubertal rats

The aim of the work is to find out peculiarities in manifestation of oxidative stress and to determine activity of enzymes, responsible for utilization of endogenous aldehydes in the mitochondrial fraction of the skeletal (femoral) muscle in pubertal rats during immobilization stress. Our study has shown that differently directed changes in the activity of mitochondrial aldehyde dehydrogenases and aldehyde reductases occur in the pubertal immobilized rats, that limits the catabolism effectiveness as regards carbonyl products offree radical oxidation in the muscle cells. Corroboration of the effect under consideration is an increased level of protein free radical oxidation products in the mitochondria of the skeletal muscle. On the basis of the obtained data the authors draw a conclusion about an increased sensitivity of the skeletal muscle to the oxidative stress impact due to modulation in the state of enzyme system, responsible for utilization of endogenous aldehydes in the mitochondria.

[The ROS-generating and antioxidant systems in the liver of rats treated with prednisolone and vitamin D3]

The mechanisms of glucocorticoid-induced disturbances of liver function is currently not fully clarified. Vitamin D3 was previously shown to play an important role in the regulation of impaired oxidative metabolism and detoxification function of the liver associated with the effects of hepatotoxic compounds. The study was undertaken to define the intensity of oxidative metabolism in the rat liver and survival of hepatocytes after prolonged prednisolone administration and to assess whether vitamin D3 is capable to counter glucocorticoid-induced changes. It has been shown that prednisolone (0.5 mg per animal for 30 days) leads to 1.6-fold increase in the percentage of necrotic cells among isolated hepatocytes as compared with the control. The glucocorticoid-induced impairment of hepatocellular function was accompanied by enhanced generation of reactive oxygen species (ROS), accumulation of TBA-active products and carbonylated proteins but reduced levels of free SH-groups of low molecular weight compounds. It was demonstrated a decrease in the activities of key enzymes of antioxidant system (SOD, catalase, glutathione peroxidase), whereas the activities of pro-oxidant enzymes NAD(P)H-quinone oxidoreductase and semicarbazide-sensitive amine oxidase were shown to be increased. Vitamin D3 (and to greater extent in combination with α-tocopherol) administration (100 IU) on the background of glucocorticoid therapy caused normalizing effects on the level of ROS formation, oxidative modification of biomolecules and activity of antioxidant enzymes resulting in better survival of hepatocytes. These data suggest a potential role of vitamin D3 in the regulation of oxidative metabolism alterations related to hepatotoxic action of glucocorticoids.

Seasonal dynamics of products of lipid peroxidation in liver of bank vole (Myodes glareolus) under conditions of environmental pollution by heavy metals

The presented research involves the integral assessment of biochemistry indexes of natural populations of voles under conditions of environmental pollution by heavy metals. The raised content of mobile forms of Pb, Cd, Cr, Ni and Co in soils was revealed for a distance of 500 m to the south-west of Tripillya Thermal Power Plant (TPP) (Kyiv region, Ukraine). It considerably (up to 3-5 times) exceeds the levels in the territory of Kaniv Nature Reserve (Cherkassy region, Ukraine). The territory of National Nature Park "Holosiivsky" (Kyiv, Ukraine) is characterized by rather increased content of active form of investigated heavy metals, especially Pb. The increase of the concentration of diene conjugates (up to 7-10 times) and thiobarbituric acid (TBA) active compounds (up to 2-3 times) in the liver of bank vole (Myodes glareolus) polluted by heavy metals has been found. The insignificant increase of the content of Schiff bases in liver homogenate of voles in the region of impact of the Tripillya TPP (2 times in spring and summer, 3 times - in autumn) was detected. Seasonal dynamics of the maintenance of lipid peroxidation products has been revealed. The registered changes of biochemical indicators evidence for availability of biochemical stress in the bank vole organism in the region of influence of the Tripillya TPP.

Rokumi-jio-gan-containing prescriptions regulate oxidative stress through improving dyslipidemia in a subtotal nephrectomized rat model

ETHNOPHARMACOLOGICAL RELEVANCE

Rokumi-jio-gan-containing prescriptions, traditional medicine, are widely used to treat renal dysfunction in Japan.

AIM OF THE STUDY

The present study was conducted to examine whether two Rokumi-jio-gan-containing prescriptions (Hachimi-jio-gan and Bakumi-jio-gan) have an ameliorative effect on dyslipidemia in nephrectomized rats.

MATERIALS AND METHODS

Each prescription was orally administered to nephrectomized rats at 150mg/kg body weight per day for 10 weeks, and its effect was compared with vehicle-treated nephrectomized rats.

RESULTS

Rats given Hachimi-jio-gan and Bakumi-jio-gan showed an improvement of renal functional parameters such as serum urea nitrogen, creatinine, creatinine clearance, and urinary protein. The increased triglyceride, total cholesterol, non-esterified fatty acid, high-density lipoprotein cholesterol, and very low-density lipoprotein cholesterol/low-density lipoprotein cholesterol levels in serum, and triglyceride and total cholesterol contents in the kidney of nephrectomized rats were significantly decreased by Hachimi-jio-gan and Bakumi-jio-gan administration. Furthermore, Hachimi-jio-gan acts as a regulator of peroxisome proliferator-activated receptor α, sterol regulatory element binding protein (SREBP)-1, and SREBP-2. On the contrary, the increased reactive oxygen species and thiobarbituric acid-reactive substance were decreased, while superoxide dismutase and the reduced glutathione/oxidized glutathione ratio were augmented by Hachimi-jio-gan rather than Bakumi-jio-gan. The improvement of nuclear factor-kappa Bp65, cyclooxygenase-2, inducible nitric oxide synthase, NF-E2-related factor 2, and heme oxygenase-1 was marked in the group administered Bakumi-jio-gan. However, oil red O staining showed that the increased lipid deposition in the kidney of nephrectomized rats improved on Hachimi-jio-gan and Bakumi-jio-gan administration.

CONCLUSION

This study provides scientific evidence that two Rokumi-jio-gan-containing prescriptions (Hachimi-jio-gan and Bakumi-jio-gan) improve oxidative stress via dyslipidemia in the remnant kidney of nephrectomized rats.

Therapeutic efficacy of melatonin in reducing retinal damage in an experimental model of early type 2 diabetes in rats

Diabetic retinopathy (DR) is a leading cause of acquired blindness in adults, mostly affected by type 2 diabetes mellitus (T2DM). We have developed an experimental model of early T2DM in adult rats which mimics some features of human T2DM at its initial stages and provokes significant retinal alterations. The aim of this work was to analyze the effect of melatonin on retinal changes induced by the moderate metabolic derangement. For this purpose, adult male Wistar rats received a control diet or 30% sucrose in the drinking water. Three weeks after this treatment, animals were injected with vehicle or streptozotocin (STZ, 25 mg/kg). One day or 3 wk after vehicle or STZ injection, animals were subcutaneously implanted with a pellet of melatonin. Fasting and postprandial glycemia, and glucose, and insulin tolerance tests were analyzed. At 12 wk of treatment, animals which received a sucrose-enriched diet and STZ showed significant differences in metabolic tests, as compared with control groups. Melatonin, which did not affect glucose metabolism in control or diabetic rats, prevented the decrease in the electroretinogram a-wave, b-wave, and oscillatory potential amplitude, and the increase in retinal lipid peroxidation, NOS activity, TNFα, Müller cells glial fibrillary acidic protein, and vascular endothelial growth factor levels. In addition, melatonin prevented the decrease in retinal catalase activity. These results indicate that melatonin protected the retina from the alterations observed in an experimental model of DR associated with type 2 diabetes.

EPR detection of paramagnetic chromium in liver of fish (Anguilla anguilla) treated with dichromate(VI) and associated oxidative stress responses-contribution to elucidation of toxicity mechanisms

The impact of chromium (Cr) on fish health has been the subject of numerous investigations, establishing a wide spectrum of toxicity, attributed particularly to the hexavalent form [Cr(VI)]. However, reports on the simultaneous assessment of Cr toxicity in fish and its toxico-kinetics, namely involving metal speciation, are scarce. Therefore, keeping in view the understanding of the mechanisms of Cr(VI) toxicity, this work intended to detect the formation of paramagnetic Cr species in liver of Anguilla anguilla following short-term dichromate(VI) intraperitoneal treatment (up to 180 min), assessing simultaneously the pro-oxidant properties. The formation of Cr(V) and Cr(III) was examined by electron paramagnetic resonance (EPR), as an innovative approach in the context of fish toxicology, and related with the levels of total Cr. Cr(V) was successfully detected and quantified by EPR spectrometry, showing a transient occurrence, mostly between 15 and 90 min post-injection, with a peak at 30 min. The limitations of EPR methodology towards the detection and quantification of Cr(III) were confirmed. Although Cr(VI) exposure induced the antioxidant system in the eel's liver, the oxidative deterioration of lipids was not prevented. Overall, the results suggested that Cr(V), as a short-lived species, did not appear to be directly and primarily responsible for the cellular damaging effects observed, since stress responses persisted up to the end of exposure regardless Cr(V) drastic decay. Though further research is needed, ROS mediated pathways (suggested by superoxide dismutase and catalase activity induction) and formation of Cr(III) complexes emerged as the most plausible mechanisms involved in Cr(VI) toxicity.

Low hydrogen sulphide and chronic kidney disease: a dangerous liaison

Hydrogen sulphide, H(2)S, is a gaseous compound involved in a number of biological responses, e.g. blood pressure, vascular function and energy metabolism. In particular, H(2)S is able to lower blood pressure, protect from injury in models of ischaemia-reperfusion and induce a hypometabolic state. In chronic kidney disease (CKD), low plasma hydrogen sulphide levels have been established in humans and in animal models. The enzymes involved in its production are cystathionine β-synthase, cystathionine γ-lyase and 3-mercaptopyruvate sulphurtransferase. The mechanisms for H(2)S decrease in CKD are related to the reduced gene expression (demonstrated in uraemic patient blood cells) and decreased protein levels (in tissues such as liver, kidney, brain in a CKD rat model). In the present Nephrol Dial Transplant issue, in fact, Aminzadeh and Vaziri document that the alterations in this pathway complicate the uraemic state and are linked to CKD progression. They furnish a time frame in CKD and record enzyme tissue distribution. It remains to be established if low H(2)S is causally linked to CKD progression and if interventions aimed to restore the status quo ante are able to modify this picture.

Effects of irradiation dose and O(2) and CO(2) concentrations in packages on foodborne pathogenic bacteria and quality of ready-to-cook seasoned ground beef product (meatball) during refrigerated storage

Combined effects of gamma irradiation and concentrations of O(2) (0, 5, 21%) and CO(2) (0, 50%) on survival of Escherichia coli O157:H7, Salmonella enteritidis, Listeria monocytogenes, lipid oxidation, and color changes in ready-to-cook seasoned ground beef (meatball) during refrigerated storage were investigated. Ground beef seasoned with mixed spices was packaged in varying O(2) and CO(2) levels and irradiated at 2 and 4 kGy. Irradiation (4 kGy) caused about 6 Log inactivation of the inoculated pathogens. Inactivation of Salmonella was 0.9- and 0.4-Log lower in 0 and 5% O(2), respectively, compared to 21% O(2). Irradiation at 2 and 4 kGy increased thiobarbituric acid reactive substances in meatballs by 0.12 and 0.28 mg malondialdehyde kg(-1), respectively, compared to control. In reduced-O(2) packages, radiation-induced oxidation was lower, and the initial color of an irradiated sample was maintained. Packaging with 0% + 50% CO(2) or 5% O(2) + 50% CO(2) maintained the oxidative and the color quality of irradiated meatballs during 14-day refrigerated storage. MAP with 5%O(2) + 50% CO(2) combined with irradiation up to 4 kGy is suggested for refrigerated meatballs to reduce the foodborne pathogen risk and to maintain the quality.

Linoleic acid-induced ultra-weak photon emission from Chlamydomonas reinhardtii as a tool for monitoring of lipid peroxidation in the cell membranes

Reactive oxygen species formed as a response to various abiotic and biotic stresses cause an oxidative damage of cellular component such are lipids, proteins and nucleic acids. Lipid peroxidation is considered as one of the major processes responsible for the oxidative damage of the polyunsaturated fatty acid in the cell membranes. Various methods such as a loss of polyunsaturated fatty acids, amount of the primary and the secondary products are used to monitor the level of lipid peroxidation. To investigate the use of ultra-weak photon emission as a non-invasive tool for monitoring of lipid peroxidation, the involvement of lipid peroxidation in ultra-weak photon emission was studied in the unicellular green alga Chlamydomonas reinhardtii. Lipid peroxidation initiated by addition of exogenous linoleic acid to the cells was monitored by ultra-weak photon emission measured with the employment of highly sensitive charged couple device camera and photomultiplier tube. It was found that the addition of linoleic acid to the cells significantly increased the ultra-weak photon emission that correlates with the accumulation of lipid peroxidation product as measured using thiobarbituric acid assay. Scavenging of hydroxyl radical by mannitol, inhibition of intrinsic lipoxygenase by catechol and removal of molecular oxygen considerably suppressed ultra-weak photon emission measured after the addition of linoleic acid. The photon emission dominated at the red region of the spectrum with emission maximum at 680 nm. These observations reveal that the oxidation of linoleic acid by hydroxyl radical and intrinsic lipoxygenase results in the ultra-weak photon emission. Electronically excited species such as excited triplet carbonyls are the likely candidates for the primary excited species formed during the lipid peroxidation, whereas chlorophylls are the final emitters of photons. We propose here that the ultra-weak photon emission can be used as a non-invasive tool for the detection of lipid peroxidation in the cell membranes.

In vitro and in vivo antioxidant properties of extracts from Coptis chinensis inflorescence

The inflorescence of cultivated Coptis chinensis has been valued for tea production for many years in China. The antioxidant activities of C. chinensis inflorescence extracts prepared by various solvents were investigated by using several established in vitro systems: 2,2'-azinobis(3-ethylbenzthiazoline-6-sulphonic acid (ABTS), α,α-diphenyl-β-picrylhydrazyl (DPPH) and superoxide radical scavenging assays, reducing power assay, and ferrothiocyanate (FTC) and thiobarbituric acid (TBA) assays. The results showed that the 70% ethanol extract (EE) had the strongest antioxidant activity in vitro among the various extracts. Based on the in vitro results, EE was used to evaluate the antioxidant activity of C. chinensis inflorescence in vivo. The liver and kidney of intoxicated animals showed a significant decrease in superoxide dismutase (SOD), catalase (CAT) and glutathione (GSH) levels, while the malondialdehyde (MDA) level showed a significant increase. These changes were significantly reversed after treatment with EE and the standard vitamin E. Thus, the C. chinensis inflorescence may be a valuable natural source that can be applicable to food industries.

Roundup effects on oxidative stress parameters and recovery pattern of Rhamdia quelen

Antioxidant enzymes and oxidative stress indicators were evaluated in fish exposed to different concentrations of the herbicide Roundup 48% (Monsanto, St. Louis, MO): control (none), 0.45, or 0.95 mg/l. After exposure for 8 days to herbicide, fish were transferred to clean water for a recovery response period (also 8 days). Herbicide increased thiobarbituric acid reactive species in liver and muscle at the higher concentration and in the brain at both concentrations. Protein carbonyl in liver increased after exposure. Catalase (CAT) and superoxide dismutase (SOD) activities and ascorbic acid levels in liver did not change in fish exposed to both concentrations. Glutathione S-transferase (GST) levels decreased at both concentrations. The nonprotein thiol levels decreased at the 0.95 mg/l concentration. During the recovery period, some of the parameters that had altered, such as protein carbonyl content, later recovered. However, some enzymes reacted during this period, e.g., GST increased its activity, possibly indicating a compensatory response against the toxic conditions. In contrast, CAT and SOD activities decreased during the recovery period, indicating herbicide toxicity. Oxidative stress that occurred during the exposure period was likely due to the increased lipid peroxidation and protein carbonyl content. The results concerning oxidative and antioxidant profiles indicate that short-term exposure to herbicide is capable of causing oxidative stress in fish tissues.

Hyperuricemia as a mediator of the proinflammatory endocrine imbalance in the adipose tissue in a murine model of the metabolic syndrome

OBJECTIVE

Hyperuricemia is strongly associated with obesity and metabolic syndrome and can predict visceral obesity and insulin resistance. Previously, we showed that soluble uric acid directly stimulated the redox-dependent proinflammatory signaling in adipocytes. In this study we demonstrate the role of hyperuricemia in the production of key adipokines.

RESEARCH DESIGN AND METHODS

We used mouse 3T3-L1 adipocytes, human primary adipocytes, and a mouse model of metabolic syndrome and hyperuricemia.

RESULTS

Uric acid induced in vitro an increase in the production (mRNA and secreted protein) of monocyte chemotactic protein-1 (MCP-1), an adipokine playing an essential role in inducing the proinflammatory state in adipocytes in obesity. In addition, uric acid caused a decrease in the production of adiponectin, an adipocyte-specific insulin sensitizer and anti-inflammatory agent. Uric acid-induced increase in MCP-1 production was blocked by scavenging superoxide or by inhibiting NADPH oxidase and by stimulating peroxisome-proliferator-activated receptor-γ with rosiglitazone. Downregulation of the adiponectin production was prevented by rosiglitazone but not by antioxidants. In obese mice with metabolic syndrome, we observed hyperuricemia. Lowering uric acid in these mice by inhibiting xanthine oxidoreductase with allopurinol could improve the proinflammatory endocrine imbalance in the adipose tissue by reducing production of MCP-1 and increasing production of adiponectin. In addition, lowering uric acid in obese mice decreased macrophage infiltration in the adipose tissue and reduced insulin resistance.

CONCLUSIONS

Hyperuricemia might be partially responsible for the proinflammatory endocrine imbalance in the adipose tissue, which is an underlying mechanism of the low-grade inflammation and insulin resistance in subjects with the metabolic syndrome.

Salvia leriifolia Benth (Lamiaceae) extract demonstrates in vitro antioxidant properties and cholinesterase inhibitory activity

The object of the present study was to investigate the in vitro antioxidant properties and cholinesterase inhibitory activity of Salvia leriifolia Benth extracts and fractions. The functional role of herbs and spices and their constituents is a hot topic in food-related plant research. Salvia species have been used since ancient times in folk medicine for cognitive brain function and have been subjected to extensive research. Thus, we hypothesize that S leriifolia, because of its functional properties, would be a good candidate to use as a nutraceutical product for improving memory in the elderly or patients affected by Alzheimer disease (ad). To test this hypothesis, we examined the cholinesterase inhibitory activity using the modified colorimetric Ellman's method against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). The n-hexane exhibited the highest activity, with inhibitory concentration 50% (IC(50)) values of 0.59 and 0.21 mg/mL, for AChE and BChE, respectively. This extract was fractionated, and 9 of these fractions (A-I) were obtained and tested. Fraction G, characterized by the presence of sesquiterpenes as major components, was the most active against AChE (IC(50) = 0.05 mg/mL). Because oxidative stress is a critical event in the pathogenesis of AD, we decided to screen the antioxidant activity (AA) using 2,2-diphenyl-1-picrylhydrazyl test, β-carotene bleaching test, and bovine brain peroxidation (thiobarbituric acid) assay. The ethyl acetate extract showed the highest activity, with IC(50) values of 2 and 33 μg/mL on β-carotene bleaching test and thiobarbituric acid test, respectively. These results suggest potential health benefits of S leriifolia extracts. However, this finding requires additional investigation in vivo.

Antioxidant status in rats after long-term intake of anthocyanins and ellagitannins from blackberries

BACKGROUND

This study reported the effects of the daily intake of anthocyanins and ellagitannins (ET) extracted from blackberries on the markers for oxidative status in healthy rats.

RESULTS

The phenolic compounds were administered from three different extracts: an aqueous extract of blackberry (BJ) and its two derived fractions: anthocyanin-enriched (AF) and ET-enriched (EF) fractions. After 35 days’ administration, the AF and EF extracts significantly reduced thiobarbituric acid reactive substance levels and increased glutathione levels in the liver,kidney and brain. Plasma antioxidant capacity increased only in the group that received AF. Antioxidant enzyme activity and expression did not follow a pattern of response varying according to the tissues and extracts. A significant increase in the catalase activity was observed only in the plasma of the groups administered anthocyanin-containing extracts,which were the BJ and AF groups. Glutathione peroxidase activity was significantly increased in the liver and brain after EF treatment, and the highest increase in its expression was observed in the livers and brains of rats that received AF and EF, respectively.

CONCLUSION

The results demonstrate that long-term intake of anthocyanin and ET through diet affects antioxidant enzymeactivity and expression, and enhances oxidative markers in healthy rats.

The Nrf2-Keap1 cellular defense pathway and heat shock protein 70 (Hsp70) response. Role in protection against oxidative stress in early neonatal unilateral ureteral obstruction (UUO)

Perturbation of renal tubular antioxidants and overproduction of reactive oxygen species may amplify the proinflammatory state of renal obstruction, culminating in oxidative stress and tubular loss. Here, we analyzed the heat shock protein 70 (Hsp70) response and the function and signal transduction of NF-E2-related protein 2 (Nrf2) transcription factor on oxidative stress modulation in obstruction. Rats were subjected to unilateral ureteral obstruction or sham operation and kidneys harvested at 5, 7, 10, and 14 days after obstruction. Hsp70 expression and Nrf2 activity and its downstream target gene products were assessed. After 10 and 14 days of obstruction, enhanced lipid peroxidation through higher thiobarbituric acid reactive substances levels and increased oxidative stress resulted in reduced total antioxidant activity and enhanced nicotinamide adenine dinucleotide phosphate reduced (NADPH) oxidase activity were demonstrated. This was accompanied by decreased inducible Hsp70 expression and a progressive reduction of nuclear Nrf2 and its target gene products glutathione S-transferase A2 (GSTA2) and NADPH/quinone oxidoreductase 1 (NQO1), whereas the Nrf2 repressor Kelch-like ECH-associated protein-1 (Keap1) was upregulated. By contrast, on early obstruction for 7 days, lack of increased oxidative markers associated with higher inducible Hsp70 protein levels and a rapid nuclear accumulation of Nrf2, Keap1 downregulation, and mRNA induction of the identified Nrf2-dependent genes, NQO1 and GSTA2, were shown. For these results, we suggest that the magnitude of cytoprotection in early obstruction depends on the combined contribution of induced activation of Nrf2 upregulating its downstream gene products and Hsp70 response. Impaired ability to mount the biological response to the prevailing oxidative stress leading to renal injury was shown in prolonged obstruction.

[State of the system of antioxidant defense in tissues of the black sea turbot during the spawning]

The system of antioxidant (AO) defense and processes of lipid peroxidation (LP) of the Black Sea turbot Psetta (Scophtalmus) maxima maeotica (L., 1758) have been investigated during the spawning season. The activity of glutathione peroxidase (GP), glutathione reductase (GR), catalase and content of reduced glutathione (GSH) and TBA-reactive products have been determined in gonads, gills, liver, red and white muscles of males and females at different stages of gonad's maturity (V and VI stages). The peculiarities of AO complex and LP depended on tissue specificity and sexual distinctions of the turbot have been found. The turbot females at VI stage were found to have the most significant changes. In gonads and liver the level of TBA-reactive products decreased. In gonads the activities of GP and GR decreased, but the level of GSH increased. In gills of these females the activity of GP and the level of GSH increased, while in the red muscles the activity of catalase raised. In white muscles the activity of GR dropped. In the males' tissues of the turbot at VI stage the growth of the activity of GP in gills and GSH content in white muscles have been found. In all tissues of males the decrease of the TBA-reactive products content has been observed.

Gastroprotective effect of barbatusin and 3-beta-hydroxy-3-deoxibarbatusin, quinonoid diterpenes isolated from Plectranthus grandis, in ethanol-induced gastric lesions in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Validate the popular use of Plectranthus grandis in gastric disorders through the active components.

AIMS

Isolation of barbatusin (BB) and 3beta-hydroxy-3-deoxibarbatusin (BBOH), diterpenes from Plectranthus grandis, and evaluation of their gastroprotective effect and possible mechanisms of action.

MATERIALS AND METHODS

Isolation and chemical characterization of diterpenes from Plectranthus grandis by chromatographic and spectroscopic methods and evaluation of gastroprotective action of the diterpenes through ethanol-induced gastric injury in mice model. It was evaluated the effect of capsazepine, indomethacin and the role of nitric oxide and K(ATP-) channels on the gastroprotective effect of BBOH and BB. Additionally it was measured the concentrations of gastric mucus, non-proteic-sulfhydryl groups and total thiobarbituric acid-reactive substances.

RESULTS

Orally administered BBOH and BB at doses of 5 and 10mg/kg, markedly reduced the gastric lesions by 59 and 96%, and 32 and 76%, respectively, with superior results as compared to N-acetylcysteine (150 mg/kg, i.p.), reference compound that caused 85% lesion suppression. Although BBOH presented a higher gastroprotection than BB they act by similar mechanisms in relation to N-acetylcysteine, and prevent the depletion of gastric mucus, gastric mucosal non-proteic-sulfhydryl groups as well as the increase in thiobarbituric acid-reactive species. Moreover, the gastroprotective effect of BB was effectively blocked in mice pretreated with TRPV1 antagonist capsazepine, by the non-selective cyclooxygenase inhibitor indomethacin, or by the nitric oxide synthase inhibitor L-NAME but not by K(+)(ATP) channel inhibitor glibenclamide. In contrast, the gastroprotective effect of BBOH was blocked only by indomethacin and glibenclamide pretreatments.

CONCLUSION

The protective role for BBOH and BB affording gastroprotection against gastric damage induced by ethanol indicates that these compounds contribute for the activity of Plectranthus species. The different modes of action are probably related to differences in their chemical structure.

Effect of a gastrin-releasing peptide receptor antagonist and a proton pump inhibitor association in an animal model of gastritis

It has been proposed that reactive oxygen species play a causative role of gastric mucosal damage induced by increased gastric secretion. Gastrin-releasing peptide is a typical neuropeptide that stimulates acid secretion by release of gastrin. In the present work we have investigated the mechanism of indomethacin (IDM)-induced gastric ulcer caused by ROS and determined the effects of a selective gastrin-releasing peptide receptor antagonist, RC-3095, alone and in association with omeprazole (OM) and compared it with an established antioxidant compound N-acetyl cysteine (NAC). Adult male Wistar rats were pre-treated for 7 days with OM, RC-3095, NAC, both drugs and water (control). The animals were then submitted to fasting for 24h; IDM was administered. Rats were killed 6h after that and the stomachs were used for evaluation of macroscopic damage and oxidative stress parameters. Our results showed that IDM increased mitochondrial superoxide production; OM and RC-3095 alone did not prevent such effect, but the combination of these drugs was effective. TBARS assay revealed that IDM-induced lipid peroxidation in gastric tissue and that OM and RC-3095, alone or in combination, prevented this effect with superior action that NAC. Finally, we verified that IDM increased protein carbonyl content and that this effect was prevented RC-3095, alone or in combination with OM, being similar to standard antioxidant. The present results support the view that, besides the inhibition of acid secretion, the protective effects exerted by OM and RC-3095 against IDM-induced gastric damage can be ascribed to a reduction of gastric oxidative injury.

Effect of arachidonic, eicosapentaenoic and docosahexaenoic acids on the oxidative status of C6 glioma cells

n-3 polyunsaturated fatty acids (PUFAs) have been described to have beneficial effects on brain development and in the prevention and treatment of brain damage. C6 glioma cells were incubated with 100 microM of either C20:4n-6 (ARA), or C20:5n-3 (EPA), or C22:6n-3 (DHA) for different time periods to assess whether these acids altered the cellular oxidative state. The ARA and EPA were promptly metabolised to C22:4n-6 and C22:5n-3, respectively, whereas DHA treatment simply increased the amount of DHA in the cells. Cell viability was not affected by ARA, while a cytotoxic effect was observed 72 h after n-3 PUFAs supplementation. The levels of reactive oxygen species and thiobarbituric acid-reactive substances were significantly higher in DHA-treated cells than in EPA- and ARA-treated groups. This modification in the oxidative cellular status was also highlighted by a significant increase in catalase activity and a decrease in glutathione content in DHA-supplemented cells. Glucose-6-phosphate dehydrogenase activity, an enzyme involved in redox regulation, and O2*- release were significantly increased both in EPA and DHA groups. The effect of DHA was more severe than that of EPA. No significant changes were observed in the ARA group with respect to untreated cells. These data show that EPA and DHA induce alterations in the oxidative status that could affect the glial function.

Hydroxyl Radical Scavenging Activity of a New Ophthalmic Viscosurgical Device

PURPOSE

To quantify the hydroxyl radical scavenging activity of a new ophthalmic viscosurgical device (OVD) based on sodium hyaluronate and hydroxypropylmethylcellulose (named VISC28) in comparison with Viscoat, Healon, and Amvisc Plus.

METHODS

The hydroxyl radicals that represent the principal free-radical species generated during phacoemulsification were produced by the Fenton reaction, and the scavenging activity of the tested viscoelastic substances was evaluated in vitro by the 2-deoxy-D-ribose (2-DR) oxidation method that produces the thiobarbituric acid-malondialdehyde (TBA-MDA), complex. An aliquot of viscosurgical formulation was added to phosphate buffer and mixed with 2-DR, Fe2 +/ethylenediaminetetraacetic acid (EDTA), and H2O2. The sample mix was incubated and thiobarbituric acid-trichloroacetic acid solution was added. The sample was then incubated for 30 min, and a chromatographic analysis was performed to quantify the TBA-MDA complex. The data were expressed as micromoles of MDA per milliliter of sample.

RESULTS

All tested OVDs showed a marked hydroxyl radical scavenging activity. The MDA level was significantly lower in VISC28 (0.045 +/- 0.007 micromol/ml) compared with Viscoat (0.070 +/- 0.012 micromol/ ml, p < 0.05), Amvisc Plus (0.111 +/- 0.008 micromol/ml, p < 0.001), and Healon (0.175 +/- 0.016 micromol/ml, p < 0.001). A reduced scavenging activity was shown by VISC28 phosphate-buffered solution (PBS) (no TRIS and no sorbitol) compared with VISC28 (p < 0.001).

CONCLUSIONS

The new OVD, VISC28, showed significantly higher hydroxyl radical inhibition compared with the other viscosurgical formulations. The following rank order for the scavenging activity was established: VISC28 > Viscoat > Amvisc Plus > Healon.

Antioxidant treatment reduces matrix metalloproteinase-2-induced vascular changes in renovascular hypertension

Mounting evidence indicates that structural and functional vascular changes associated with two-kidney, one-clip (2K-1C) hypertension result, at least in part, from altered activity of matrix metalloproteinases (MMPs). Because MMPs are upregulated by increased formation of reactive oxygen species (ROS), we hypothesized that antioxidant approaches could attenuate the increases in MMP-2 expression/activity and the vascular dysfunction and remodeling associated with 2K-1C hypertension. Sham-operated or 2K-1C hypertensive rats were treated with tempol 18 mg/kg/day or apocyanin 25 mg/kg/day (or vehicle). Systolic blood pressure was monitored weekly. After 8 weeks of treatment, aortic rings were isolated to assess endothelium-dependent and -independent relaxation. Quantitative morphometry of structural changes in the aortic wall was studied in hematoxylin/eosin sections. Aortic and systemic ROS levels were measured using dihydroethidine and thiobarbituric acid-reactive substances, respectively. Aortic MMP-2 levels and activity were determined by gelatin and in situ zymography, fluorimetry, and immunohistochemistry. Tempol and apocyanin attenuated 2K-1C hypertension (181+/-20.8 and 192+/-17.6 mm Hg, respectively, versus 213+/-18 mm Hg in hypertensive controls; both p<0.05) and prevented the reduction in endothelium-dependent vasorelaxation found in 2K-1C rats. Tempol, but not apocyanin (p>0.05), prevented the vascular remodeling found in 2K-1C rats (all p<0.01). Tempol was more effective than apocyanin in attenuating hypertension-induced increases in oxidative stress (both p<0.05), MMP-2 levels, and MMP-2 activity in hypertensive rats (all p<0.05). Our results suggest that antioxidant approaches decrease MMP-2 upregulation and attenuate the vascular dysfunction and remodeling during 2K-1C hypertension.

Simultaneous mechanical stiffness and electrical potential measurements of living vascular endothelial cells using combined atomic force and epifluorescence microscopy

The degree of mechanical stiffness of vascular endothelial cells determines the endogenous production of the vasodilating gas nitric oxide (NO). However, the underlying mechanisms are not yet understood. Experiments on vascular endothelial cells suggest that the electrical plasma membrane potential is involved in this regulatory process. To test this hypothesis we developed a technique that simultaneously measures the electrical membrane potential and stiffness of vascular endothelial cells (GM7373 cell line derived from bovine aortic endothelium) under continuous perfusion with physiological electrolyte solution. The cellular stiffness was determined by nano-indentation using an atomic force microscope (AFM) while the electrical membrane potential was measured with bis-oxonol, a voltage-reporting fluorescent dye. These two methods were combined using an AFM attached to an epifluorescence microscope. The electrical membrane potential and mechanical stiffness of the same cell were continuously recorded for a time span of 5 min. Fast fluctuations (in the range of seconds) of both the electrical membrane potential and mechanical stiffness could be observed that were not related to each other. In contrast, slow cell depolarizations (in the range of minutes) were paralleled by significant increases in mechanical stiffness. In conclusion, using the combined AFM-fluorescence technique we monitored for the first time simultaneously the electrical plasma membrane potential and mechanical stiffness in a living cell. Vascular endothelial cells exhibit oscillatory non-synchronized waves of electrical potential and mechanical stiffness. The sustained membrane depolarization, however, is paralleled by a concomitant increase of cell stiffness. The described method is applicable for any fluorophore, which opens new perspectives in biomedical research.

Defining hybrid poplar (Populus deltoides x Populus trichocarpa) tolerance to ozone: identifying key parameters

This study examined whether two genotypes of hybrid poplar (Populus deltoides x Populus trichocarpa), previously classified as ozone tolerant and ozone sensitive, had differing physiological and biochemical responses when fumigated with 120 nL L(-1) ozone for 6 h per day for eight consecutive days. Isoprene emission rate, ozone uptake and a number of physiological and biochemical parameters were investigated before, during and after fumigation with ozone. Previous studies have shown that isoprene protects plants against oxidative stress. Therefore, it was hypothesized that these two genotypes would differ in either their basal isoprene emission rates or in the response of isoprene to fumigation by ozone. Our results showed that the basal emission rates of isoprene, physiological responses and ozone uptake rates were all similar. However, significant differences were found in visible damage, carotenoids, hydrogen peroxide (H(2)O(2)), thiobarbituric acid reactions (TBARS) and post-fumigation isoprene emission rates. It is shown that, although the classification of ozone tolerance or sensitivity had been previously clearly and carefully defined using one particular set of parameters, assessment of other key variables does not necessarily lead to the same conclusions. Thus, it may be necessary to reconsider the way in which plants are classified as ozone tolerant or sensitive.

[Activity of GSH-dependent enzymes in blood serum of patients with acute and chronic pancreatitis]

INTRODUCTION

Since one of the many proposed factors in the pathogenesis of acute and chronic pancreatitis is oxidative stress, the aim of the research was evaluation of antioxidant defense mechanisms, with particular emphasis on the role of reduced glutathione and GSH-dependent enzymes.

MATERIAL AND METHODS

The study involved a group of 35 patients with pancreatitis treated at the Clinic of General Surgery and Transplantation Medical University of Warsaw in the period from 2005 to 2007. This group consisted of 20 patients with mild symptoms (edema) of the form of acute pancreatitis and 15 patients with chronic pancreatitis, short duration of the disease. In all patients with acute and chronic pancreatitis qualified for the study were measured in serum markers of oxidative stress: concentrations of reactive thiobarbituric acid (TBARS), which determines the level of lipid peroxidation and reduced levels of glutathione (GSH) and activity of antioxidant enzymes: total glutathione peroxidase (cal. GSHPx), glutathione S-transferase (GST) and glutathione reductase (GSHR).

RESULTS

We found increased lipid peroxidation level, decreased level of GSH, and changes in activity of GSH-dependent enzymes in blood serum of patients with acute and chronic pancreatitis, compared to blood serum from healthy persons.

CONCLUSIONS

Obtained results indicate participation of oxidative stress in pathogenesis of those diseases, and systemic impairment of antioxidative mechanisms.

Modulation of radiation-induced biochemical changes in cerebrum of Swiss albino mice by Grewia Asiatica

The present study evaluates the possible radioprotective effect of Grewia asiatica fruit (rich in anthocyanin, carotenes, vitamin C, etc.) pulp extract (GAE) on cerebrum of Swiss albino mice exposed to 5 Gy gamma radiation. For this, healthy mice from an inbred colony were divided into four groups: (1) Control (vehicle treated) (2) GAE treated - mice in this group were orally supplemented with GAE (700 m/kg. b.w./day) once daily for fifteen consecutive days, (3) Vehicle treated irradiated mice, and (4) GAE + Irradiated - Mice in this group received distilled water orally equivalent to GAE (700 m/kg. b.w/day) for fifteen days consecutively. Mice were sacrificed at various intervals viz. 1-30 days. Radiation-induced augmentation in the levels of lipid peroxidation of mice cerebrum was significantly ameliorated by GAE pretreatment. Radiation-induced depletion in the level of glutathione and protein was prevented significantly by GAE administration.

Excitatory effects of human immunodeficiency virus 1 Tat on cultured rat cerebral cortical neurons

Human immunodeficiency virus 1 (HIV-1) Tat protein is one of the neurotoxins involved in the pathogenesis of HIV-1-associated neuronal disorders. Combined electrophysiological and optical imaging experiments were undertaken to investigate whether HIV-1 Tat30-86, herein referred to as Tat30-86, acted directly or indirectly via the release of glutamate or both and to test its effect on the properties of spontaneous quantal events in cultured cortical neurons. Whole-cell patch recordings were made from cultured rat cortical neurons in either current- or voltage-clamp mode. Tat30-86 (50-1000 nM) induced in a population of cortical neurons a long-lasting depolarization, which was accompanied by a decrease of membrane resistance and persisted in a Krebs solution containing tetrodotoxin (TTX, 0.5 microM). Depolarizations were slightly reduced by pretreatment with glutamate receptor antagonists 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) (10 microM) and d-2-amino-5-phosphonovaleric acid (AP-5) (50 microM), and were markedly reduced in a Ca(2+)-free Krebs solution; the differences were statistically significant. Tat30-86-induced inward currents had a reversal potential between -30 and 0 mV. While not causing a noticeable depolarization, lower concentrations of Tat30-86 (10 nM) increased membrane excitability, as indicated by increased numbers of neuronal discharge in response to a step depolarizing pulse. Tat30-86 (10 nM) increased the frequency of spontaneous miniature excitatory postsynaptic currents (mEPSCs), while not significantly affecting their amplitude. Tat30-86 (10 nM) moderately increased the frequency as well as the amplitude of spontaneous miniature inhibitory postsynaptic currents (mIPSCs). Ratiometric Ca(2+) imaging studies showed that Tat30-86 produced three types of Ca(2+) responses: 1) a fast and transitory increase, 2) Ca(2+) oscillations, and 3) a fast increase followed by a plateau; the glutamate receptor antagonists eliminated the late component of Ca(2+) response. The result suggests that Tat30-86 is an active fragment and that it excites cortical neurons directly and indirectly via releasing glutamate from adjacent neurons.

Prevention by melatonin of hepatocarcinogenesis in rats injected with N-nitrosodiethylamine

N-nitrosodiethylamine (NDEA) is a potent carcinogenic agent that induces liver cancer. To evaluate the chemopreventive function of melatonin in this experimental model, Wistar male rats received a single i.p. injection of NDEA or vehicle followed by weekly s.c. injections of carbon tetrachloride or vehicle for 6 weeks. Melatonin (5 mg/kg body weight) or its vehicle (0.5 mL saline) was given i.p. on a daily basis 2 hr before lights off for 20 wk. At the end of this period the rats were killed and liver and blood samples were taken for histological and biochemical studies. As markers for liver function, the activity of aspartate transaminase (AST) and alanine transaminase (ALT) and the levels of alpha-fetoprotein were measured in serum. To assess lipid peroxidation and the antioxidant status in liver and blood, the levels of thiobarbituric acid reactive substances (TBARS) and of reduced glutathione (GSH) were measured. The activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione S-transferase (GST) was assessed in liver and erythrocyte fraction of NDEA-treated rats. NDEA administration inhibited body weight, macro- and microscopically detectable liver tumors and increased levels of plasma AST, ALT and alpha-fetoprotein. NDEA treatment decreased liver TBARS levels and CAT and SOD activities and increased liver GSH levels and GST and GPx activities. Plasma TBARS were augmented, while plasma GSH levels and the activities of erythrocyte CAT, SOD, GST and GPx decreased, in NDEA-treated rats. Melatonin administration significantly curtailed tumor development and counteracted all the biochemical effects.

Commonly used tropical medicinal plants exhibt distinct in vitro antioxidant activities against hepatotoxins in rat liver

Lipid peroxidation in biological systems has been considered as one of the major mechanisms of cell injury in aerobic organisms subjected to oxidation stress. Plants, among other functions, are considered to act as free radical scavengers and as antioxidants. Iron II (Fe(2+)), sodium nitroprusside (SNP) and nitropropionic acid stimulate the production of free radicals and lipid peroxidation. In this study, four commonly used tropical medicinal plants (Kigelia africana, Calotropis procera, Hibiscus sabdariffa and Alchornea cordifolia) were studied (in vitro) for their effects on the formation of thiobarbituric acid reactive substances (TBARS) induced by different pro-oxidants (10 microM FeSO(4), 5 microM -sodium SNP and 2mM 3-nitropropionic acid) in rat liver homogenate. All the pro-oxidants significantly increased (P<0.05) the formation of TBARS, which indicates increased lipid peroxidation in the rat liver (in vitro). However, all the plant extracts statistically (P<0.05) reduced the production of TBARS in a concentration-dependent manner in all the tested pro-oxidant-induced oxidative stresses. Alchornea cordifolia appeared to offer the highest protection. The results of the present study suggest that the use of these plants in the treatment of various diseases, especially liver disease, is probably due to their ability to act as antioxidants.

Abdominal aortic aneurysm or aortic occlusive disease: role of trace element imbalance

The nature of the relationship between atheromatous disease and degenerative aneurysm is yet to be defined. The purpose of this study was to compare tissue Fe, Cu, Zn, and thiobarbituric acid reactive substances (TBARS) levels (as a marker of lipid peroxidation) in the abdominal aorta in relation to the development of aneurysmal and occlusive disease in the infrarenal aorta. This was a prospective clinical study in an institutional referral center, in hospitalized patients. Eighty male patients who underwent surgery for abdominal aortic aneurysm (AAA) or aortic occlusive disease (AOD) were included in the study. Age, risk factors and comorbid conditions were recorded, including diabetes mellitus, hypertension, coronary artery disease, smoking, and chronic obstructive pulmonary disease. Aortic wall biopsies were collected at operation from the anterolateral section of the infrarenal aorta. Tissue Fe, Cu, Zn, and TBARS levels were determined. The mean age of the AAA group was 66.2 (56-75) years and of the AOD group 57.8 (47-72) years (p <0.001). There was a higher prevalence of hypertension in AAA patients compared to AOD patients (62.5%, 35% respectively; p <0.05). The comparison of tissue Zn levels showed no significant difference. Tissue levels of Fe, Cu, and TBARS were found to be higher in the AAA group, compared with the AOD group (p<0.001 for each). These results suggest that higher oxidative stress as a result of higher Fe and Cu levels in the AAA, compared with AOD, may be one of the contributing factors in aneurysmal formation as a result of promoted wall erosion.

Diallyl tetrasulfide modulates the cadmium-induced impairment of membrane bound enzymes in rats

Cadmium (Cd) induces extensive membrane damage that contributes to the cytotoxic effect of Cd. We studied the effect of diallyl tetrasulfide (DTS) from garlic on Cd-induced changes in lipid peroxidation and membrane-bound enzymes in liver, kidney, and testis of rats. Cadmium exposure (3 mg/kg body weight, s.c) for 3 weeks induced a significant elevation in the levels of lipid peroxidation markers (thiobarbituric acid substances and lipid hydroperoxides) with a significant decrease in the activities of membrane bound ATPases (Na+/K+ ATPase, Ca2+ ATPase, Mg2+ ATPase), the indicators of membrane function in liver, kidney and testis. The oral administration of DTS (40 mg/kg body weight) along with Cd significantly decreased the level of lipid peroxidation and significantly restored the activities of membrane bound ATPases. The results of our study suggest that DTS attenuates lipid peroxidation in tissues and promotes the stability of the membrane by protecting it from Cd-induced alterations.

Effect of tetrahydrocurcumin on lipid peroxidation and lipids in streptozotocin-nicotinamide-induced diabetic rats

Hyperlipidaemia is an associated complication of diabetes mellitus. We recently reported that tetrahydrocurcumin lowered the blood glucose in diabetic rats. In the present study, we have investigated the effect of tetrahydrocurcumin, one of the active metabolites of curcumin on lipid profile and lipid peroxidation in streptozotocin-nicotinamide-induced diabetic rats. Tetrahydrocurcumin 80 mg/kg body weight was administered orally to diabetic rats for 45 days, resulted a significant reduction in blood glucose and significant increase in plasma insulin in diabetic rats, which proved its antidiabetic effect. Tetrahydrocurcumin also caused a significant reduction in lipid peroxidation (thiobarbituric acid reactive substances and hydroperoxides) and lipids (cholesterol, triglycerides, free fatty acids and phospholipids) in serum and tissues, suggesting its role in protection against lipid peroxidation and its antihyperlipidemic effect. Tetrahydrocurcumin showed a better effect when compared with curcumin. Results of the present study indicate that tetrahydrocurcumin showed antihyperlipidaemic effect in addition to its antidiabetic effect in type 2 diabetic rats.

Antagonistic effects of methyl-mercury and PCB153 on PC12 cells after a combined and simultaneous exposure

The study of interactions for those substances which tend to accumulate in food and affect the nervous system appears to be a fundamental point to characterize the combined exposure in vitro. In this study we included two food contaminants which are known neurotoxicants: methyl-mercury (Me-Hg) and the ortho-substituted PCB 153. PC12 cells were treated with Me-Hg (range 1e-7, 2e-6 M) and PCB153 (range 1e-5, 4e-4 M) in single and combined synchronous experiments and a mathematical model was set up according to the Loewe additivity criterion to evaluate the level of interaction between toxicants, using viability as end-point. At some concentrations (Me-Hg 5e-7 M and PCB153 1e-4 and 2e-4 M; Me-Hg 1e-6M and PCB153 5e-5 M; Me-Hg 1e-7 M and PCB153 4e-4 M), a statistically significant antagonist effect was observed. No interaction was observed for other combinations. The analysis of other toxicological parameters known to be modified in single exposure experiments (TBARS and intra-cellular dopamine) confirmed the viability results. The results of our work represent a starting point to generate novel information on the interactions between PCB153 and Me-Hg in vitro, as well as a new relevant experimental and mathematical approach useful to investigate the effects of different toxicant mixtures.

Melatonin reduces oxidative stress in erythrocytes and plasma of senescence-accelerated mice

It has been suggested that oxidative stress is a feature of aging. The goal of the present study was to assess the oxidant effects related to aging and the protective role of exogenous melatonin in senescence-accelerated mice (SAMP8). Two groups of SAMP8 mice (males and females) were compared with their respective control groups of SAMR1 mice (senescence-resistant inbred strain) to determine their oxidative status without melatonin treatment. Four other groups of the same characteristics were treated with melatonin (10 mg/kg/day) in their drinking water. The melatonin concentration in the feeding bottles was titrated according to water consumption and body weight (i.e. 0.06 mg/mL for 30 g of body weight and 5 mL/day of water consumption). The treatment began when animals were 1-month old and continued for 9 months. When mice were 10-month old, they were anesthetized and blood was obtained. Plasma and erythrocytes were processed to examine oxidative stress markers: reduced glutathione (GSH), oxidized glutathione (GSSG), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), glutathione reductase (GR), glutathione S-transferase (GST), thiobarbituric acid reactive substances (TBARS), and hemolysis. The results showed greater oxidative stress in SAMP8 than in SAMR1, largely because of a decrease in GSH levels and to an increase in GSSG and TBARS with the subsequent induction of the antioxidant enzymes GPX and GR. Melatonin, as an antioxidant molecule, improved the glutathione-related parameters, prevented the induction of GPX in senescent groups, and promoted a decrease in SOD and TBARS in almost all the groups.

Rapid assessment of the physiological status of Streptococcus macedonicus by flow cytometry and fluorescence probes

Flow cytometry in combination with fluorescence probes was applied to rapidly assess the physiological status of Streptococcus macedonicus ACA-DC 198, a newly described member of the lactic acid bacteria group with technologically important features (e.g. lantibiotic production). A sonication procedure was developed for disaggregating typical streptococci chains in order to optimize cell preparations for single cell analysis. Single stained live and dead populations of S. macedonicus cells were clearly resolved based on membrane potential by bis-oxonol [DiBAC(4)(3)], membrane integrity by Propidium Iodide (PI) and enzymatic activity as well as membrane integrity by Carboxyfluorescein Diacetate (cFDA). Further, estimation of both live and dead cells by a cFDA/PI two-colour flow cytometric assay showed excellent correlation with the dead cells in the samples (dead(FCM)=0.9945 dead(S)-0.806, R(2)=0.9986 and live(FCM)=-0.978 dead(S)+98.895, R(2)=0.9992). Finally, the assay was applied to study the physiology of S. macedonicus after acid stress. Interestingly, in situ assessment of the physiological status of stressed S. macedonicus cells by flow cytometry and single cell sorting revealed the coexistence of three distinct subpopulations according to their fluorescence labelling behaviour and culturability, representing intact/culturable, permeabilized/dead and potentially injured cells with the latter exhibiting both metabolic activity and membrane permeabilization as well as decreased culturability.

Contribution of peroxidized cardiolipin to inactivation of bovine heart cytochrome c oxidase

The lipid-soluble peroxides, tert-butyl hydroperoxide and peroxidized cardiolipin, each react with bovine cytochrome c oxidase and cause a loss of electron-transport activity. Coinciding with loss of activity is oxidation of Trp19 and Trp48 within subunits VIIc and IV, and partial dissociation of subunits VIa and VIIa. tert-Butyl hydroperoxide initiates these structural and functional changes of cytochrome c oxidase by three mechanisms: (1) radical generation at the binuclear center; (2) direct oxidation of Trp19 and Trp48; and (3) peroxidation of bound cardiolipin. All three mechanisms contribute to inactivation since blocking a single mechanism only partially prevents oxidative damage. The first mechanism is similar to that described for hydrogen peroxide [Biochemistry43:1003-1009; 2004], while the second and third mechanism are unique to organic hydroperoxides. Peroxidized cardiolipin inactivates cytochrome c oxidase in the absence of tert-butyl hydroperoxide and oxidizes the same tryptophans within the nuclear-encoded subunits. Peroxidized cardiolipin also inactivates cardiolipin-free cytochrome c oxidase rather than restoring full activity. Cardiolipin-free cytochrome c oxidase, although it does not contain cardiolipin, is still inactivated by tert-butyl hydroperoxide, indicating that the other oxidation products contribute to the inactivation of cytochrome c oxidase. We conclude that both peroxidized cardiolipin and tert-butyl hydroperoxide react with and triggers a cascade of structural alterations within cytochrome c oxidase. The summation of these events leads to cytochrome c oxidase inactivation.

[The influence of anthocyanins from Aronia melanocarpa on selected parameters of oxidative stress and microelements contents in men with hypercholesterolemia]

THE AIM OF THE STUDY

Our investigations was to estimate the influence of Aronia anthocyanins (Aronox by Agropharm) on selected parameters of oxidative and antioxidative balance as well as on the concentration of selected metals in red blood cells in men with hipercholesterolaemia.

MATERIAL AND METHODS

16 men aged 27 +/- 6.4 years old with blood cholesterol concentration on the level of 205-250 mg/dl took 240 mg of anthocyanins a day for 30 days. Before and after the period of anthocyanins administration a blood sample was taken and following parameters were estimated: lead, aluminium, cooper and zinc concentration in erythrocytes with the method of atomic emission spectrometry with induced coupling plasma (AES-ICP), concentration of substances reacting with thiobarbituric acid (TBARS) and superoxide dismutase, glutathione peroxidase and catalase activities in hemolysate.

CONCLUSION

30 days long administration of 240 mg of anthocyanins a day, caused a substantial increase of glutathione peroxidase and catalase activities. The lead, aluminium and cooper concentration was decreased while zinc concentration in red blood cells was increased.

Possible Reasons for Difference in Sensitivity to Oxygen of Two Escherichia coli Strains

In preliminary experiments it was found that Escherichia coli strains AB1157 and KS400 are different in their abilities to grow under various oxygen levels in cultivation medium: the first strain does not grow under high oxygen conditions, unlike the second one. To investigate whether the damage to cellular components due to production of reactive oxygen species (ROS) was responsible for this difference, the intensity of free radical oxidation of proteins and lipids as well as the activities of selected antioxidant and associated enzymes (superoxide dismutase, catalase, peroxidase, glutathione reductase, glucose-6-phosphate dehydrogenase) were compared in the two strains. The level of thiobarbituric acid-reactive substances was 1.8-2.5-fold higher in AB1157 than in KS400, but the concentration of carbonyl proteins was lower in the AB1157 strain. In both strains growth under higher oxygen levels resulted in higher superoxide dismutase and peroxidase activities in both exponential and stationary phases. Overall, the activities of antioxidant enzymes were always higher in the KS400 strain than in AB1157. The results for both lipid and protein oxidative damage and antioxidant enzyme activities suggest that the differences in oxygen tolerance between these two strains may be due to their different abilities to cope with ROS.

Symbiosis-induced adaptation to oxidative stress

Cnidarians in symbiosis with photosynthetic protists must withstand daily hyperoxic/anoxic transitions within their host cells. Comparative studies between symbiotic (Anemonia viridis) and non-symbiotic (Actinia schmidti) sea anemones show striking differences in their response to oxidative stress. First, the basal expression of SOD is very different. Symbiotic animal cells have a higher isoform diversity (number and classes)and a higher activity than the non-symbiotic cells. Second, the symbiotic animal cells of A. viridis also maintain unaltered basal values for cellular damage when exposed to experimental hyperoxia (100% O2) or to experimental thermal stress (elevated temperature +7°C above ambient). Under such conditions, A. schmidti modifies its SOD activity significantly. Electrophoretic patterns diversify, global activities diminish and cell damage biomarkers increase. These data suggest symbiotic cells adapt to stress while non-symbiotic cells remain acutely sensitive. In addition to being toxic, high O2 partial pressure(PO2) may also constitute a preconditioning step for symbiotic animal cells, leading to an adaptation to the hyperoxic condition and, thus, to oxidative stress. Furthermore, in aposymbiotic animal cells of A. viridis, repression of some animal SOD isoforms is observed. Meanwhile, in cultured symbionts, new activity bands are induced,suggesting that the host might protect its zooxanthellae in hospite. Similar results have been observed in other symbiotic organisms, such as the sea anemone Aiptasia pulchella and the scleractinian coral Stylophora pistillata. Molecular or physical interactions between the two symbiotic partners may explain such variations in SOD activity and might confer oxidative stress tolerance to the animal host.

Effects of short-term and long-term depleted uranium exposure on open-field behavior and brain lipid oxidation in rats

Male and female rats were exposed to depleted uranium acetate (DU) in drinking water at doses of 0, 75, or 150 mg/L for either 2 weeks or 6 months. After exposure, the animals were tested for behaviors in the open-field. After testing in the open-field, the brains were examined for levels of lipid oxidation using the thiobarbituric acid (TBA) assay. Behavioral differences (line crossing and rearing) were seen in male rats after 2 weeks exposure to DU in drinking water for the highest dose group. Increased brain lipid oxidation was seen for the highest dose group for both genders. Lipid oxidation levels correlated significantly with line crossing and rearing in the open-field. After 6 months exposure, behavioral differences for male rats in the open-field remained and expanded to include other behaviors (grooming, defecation, and urination). Female rats also demonstrated some behavioral changes after 6 months exposure. Lipid oxidation in the brain continued to be seen; however, these levels no longer correlated with open-field behaviors. These data suggest that DU is a toxin that crosses the blood-brain barrier, producing behavioral changes in male rats and lipid oxidation regardless of gender in as little as 2 weeks in the rat. Longer exposures to DU may produce greater behavioral changes but compensatory mechanisms may reduce the effects of lipid oxidation. Males appear to be more sensitive to the behavioral effects of DU.

Ultrastructural changes of rat cardiac myocytes in a time-dependent manner after traumatic brain injury

We suggest an ultrastructural scoring system to evaluate the degree of damage in a time-dependent manner in cardiac myocytes after traumatic brain injury (TBI). Forty Wistar-Albino female rats weighing 170-200 g were randomly allocated into five groups. Group 1 was the control and Group 2 was the sham-operated group. Group 3, Group 4 and Group 5 were trauma groups. Weight-drop technique was used for achieving TBI. Lipid peroxidation was estimated by thiobarbituric acid test. An electron microscopic scoring model was used to grade the subcellular changes. Results of heart injury score (HIS) showed that the 24-h trauma group had statistically significant levels in nuclear damage compared with the other groups (p < 0.05). Sarcoplasmic reticulum and mitochondria scores of all trauma groups were significantly different from the control and sham groups (p < 0.05). The results showed that lipid per oxidation levels were statistically significant different between the control and all trauma groups (p < 0.05). The electron microscopic scoring model worked well in depicting the traumatic changes, which were supported by lipid peroxidation levels. Traumatic brain injury produced obvious gradual damage on the ultrastructure of the cardiac myocytes and this damage was more significant in the 24-h trauma group.

Antioxidant properties of flavone-6(4′)-carboxaldehyde oxime ether derivatives

The in vitro antioxidant properties of some flavone-6(4)-carboxaldehyde oxime ether derivatives (Ia-f, IIa-f) were determined by their effects on the rat liver microsomal NADPH-dependent lipid peroxidation (LP) levels by measuring the formation of 2-thiobarbituric acid reactive substances. The free radical scavenging properties of the compounds were also examined in vitro by determining their capacity to scavenge superoxide anions and interact with the stable free radical 2, 2-diphenyl-1-picrylhydrazyl (DPPH). The most active compounds, IIb (Flavone-4'-carboxaldehyde-O-ethyl oxime) and Id (Flavone-6-carboxaldehyde-O-[2-(1-pyrolidino) ethyl] oxime), caused 98 and 79% inhibition of superoxide anion production and DPPH stable free radical at 10(-3) M, respectively.

Effect of an acute dose of ethanol on lipid peroxidation in rats: action of vitamin E

Free radical generation is an important step in the pathogenesis of ethanol-associated liver injury. Administration of ethanol induces an increase in lipid peroxidation both by enhancing the production of oxygen reactive species and by decreasing the levels of endogenous antioxidants. This work focuses on the generation of free radicals provoked by an acute ethanol dose in rats, and the role of different dietary levels of vitamin E. The objective of this investigation was to study the effect of three different dietary levels of vitamin E (deficient, control and supplemented with 20 times higher levels) on plasma and liver lipid peroxidation (assayed by TBARS), vitamin E in plasma and liver, and hepatic glutathione concentration, in rats receiving the different diets. The animals were submitted to an acute dose of ethanol (5 g/kg body weight) administered by gavage at the end of an experimental 4 week period and were sacrificed at 0, 2, 4, 8 and 24 h after ethanol administration. Dietary vitamin E caused a dose-dependent increase in liver and plasma concentration of the vitamin, but ethanol administration decreased hepatic vitamin E in all groups. TBARS concentrations were higher in liver of rats that received the deficient diet, independent of ethanol, however, liver TBARS concentrations were low in control and supplemented groups, but increased with ethanol ingestion. Glutathione levels were lowered by ethanol administration in all groups, in different times, but recovered to this original level in 24 h time. In conclusion, vitamin E deficiency alone induces liver lipid peroxidation in rats, acute administration of ethanol affect vitamin E and GSH level and maintenance of adequate or higher vitamin E levels acts as a protective factor against free radical generation.