Changes In Oxidative Stress Parameters Research Articles

P-52 - Oxidative stress and antioxidant defense parameters in different diseases: ethnic aspects

Numerous researches show that data on an ethnic origin can give additional information for the personified approach in treatment of different diseases. The aim of this study was to compare oxidative stress and antioxidant defense parameters in patients with Type 1 Diabetes Mellitus (T1DM) and arterial hypertension (AH) of two ethnic groups. Patients with T1DM (Mongoloids (n=72) and Caucasians (n=50)) and with AH (Mongoloids (n=40) and Caucasians (n=102)) were examined. Spectrophotometric and fluorometric methods were used. In Mongoloid-patients with T1DM there has been marked increased conjugated dienes (СDs) for 34% and increased total antioxidant activity parameter (TAA) for 54%; in Caucasian-patients with T1DM were increased thiobarbituric acid reactants for 50% and decreased TAA level for 23% compare to controls. СDs in Mongoloids and Caucasians with AH compare to the control were increased. TAAs level in Mongoloids with AH were higher compare to control for 20% and superoxide dismutase activity in Mongoloids with AH were higher for 22% compare to the Caucasians. Changes in oxidative stress parameters in Mongoloid-patients are characterized by low intensity, which is probably due to the increased activity of the antioxidant defense system.

Combinatorial drug delivery strategy employing nano-curcumin and nano-MiADMSA for the treatment of arsenic intoxication in mouse

Chelation therapy is the mainstream treatment for heavy metal poisoning. Apart from this, therapy using antioxidant/herbal extracts are the other strategies now commonly being tried for the treatment. We have previously reported individual beneficial efficacy of nanoparticle mediated administration of an antioxidant like ‘curcumin’ and an arsenic chelator ‘monoisoamyl 2,3-dimercaptosuccinic acid (MiADMSA)’ for the treatment of arsenic toxicity compared to bulk drugs. The present paper investigates our hypothesis that a combination drug delivery therapy employing two nanosystems, a chelator and a strong antioxidant, may produce more pronounced therapeutic effects compared to individual effects in the treatment of arsenic toxicity.An in-vivo study was conducted wherein arsenic as sodium arsenite (100 ppm) was administered in drinking water for 5 months to Swiss albino mice. This was followed by a treatment protocol comprising of curcumin encapsulated chitosan nanoparticles (nano-curcumin, 15 mg/kg, orally for 1 month) either alone or in combination with MiADMSA encapsulated polymeric nanoparticles (nano-MiADMSA, 50 mg/kg for last 5 days) to evaluate the therapeutic potential of the combination treatment. Our results demonstrated that co-treatment with nano-curcumin and nano-MiADMSA provided beneficial effects in a synergistic way on the adverse changes in oxidative stress parameters and metal status induced by arsenic.

Aerobic and strength training induce changes in oxidative stress parameters and elicit modifications of various cellular components in skeletal muscle of aged rats

Skeletal muscle aging is associated with loss of mass, function, and strength-a condition known as sarcopenia. It has been reported that sarcopenia can be attenuated by physical exercise. Therefore, we investigated whether 2 different physical exercise protocols could modulate and induce changes in oxidative and inflammatory parameters, as well as in BDNF and DNA repair enzyme levels in skeletal muscle tissue of aged rats. Aging Wistar rats performed treadmill or strength training for 50 min 3 to 4 times a week for 8 weeks. Strength training decreased 2′,7′-dichlorofluorescein (DCFH) oxidation (P = 0.0062); however, nitric oxide, protein deglycase DJ-1, and tumor necrosis factor alpha (TNF-α) levels increased after aerobic training (P = 0.04, P = 0.027 and P = 0.009, respectively). Both exercise protocols increased superoxide dismutase (SOD) and catalase (CAT) activity (P = 0.0017 and P = 0.0326) whereas the activity of glutathione (GSH) (P = 0.0001) was decreased. Brain-derived neurotropic factor (BDNF) levels were not affected by exercise, but 8-oxoguanine glycosylase (OGG1) decreased after strength training (P = 0.0007). In conclusion, oxidative parameters showed that skeletal muscle adapt to increased ROS levels, reducing the risk of free radical damage to the tissue after both exercise protocols. These results show that the effects of physical exercise on skeletal muscle are mediated in an exercise type-dependent manner.

Early decrease of oxidative stress by non-invasive ventilation in patients with acute respiratory failure.

Oxidative stress plays an important role in chronic respiratory diseases where the use of non-invasive ventilation seems to reduce the oxidative damage. Data on acute respiratory failure are still lacking. The aim of the study is to investigate the interplay between oxidative stress and acute respiratory failure, and the role of non-invasive ventilation in this setting. We enrolled 60 patients suffering from acute respiratory failure (PaO2/FiO2 ratio <300): 30 consecutive patients treated with non-invasive ventilation and 30 consecutive patients treated with conventional oxygen therapy. Serum levels of soluble Nox2-derived peptide (sNOX2-dp), a marker of NADPH-oxidase activation, and 8-iso-PGF2α and H2O2, markers of oxidative stress, were evaluated at baseline and after 3h of treatment. At baseline, higher values of sNOX2-dp, 8-iso-PGF2α and H2O2 are associated with lower values of PaO2/FiO2 ratio (p<0.001). After 3h, serum levels of sNOX2-dp, H2O2, and 8-iso-PGF2α significantly decrease in patients treated with non-invasive ventilation, but not in patients treated with conventional oxygen therapy. Delta changes of oxidative stress parameters correlate inversely with the delta changes of PaO2/FiO2 (R=-0.623, p<0.001 for sNOX2-dp; R=-0.428, p<0.001 for H2O2; R=-0.548, p<0.001 for 8-iso-PGF2α). In the acute respiratory failure setting, treatment with non-invasive ventilation reduces the levels of oxidative stress in the first hours. This reduction is associated with an improvement of PaO2/FiO2 ratio as well as in a reduction of NADPH-oxidase activity.

Ammonia exposure and subsequent recovery trigger oxidative stress responses in juveniles of Brazilian flounder Paralichthys orbignyanus.

The effects of ammonia exposure and recovery on oxidative stress parameters and histology of juvenile Brazilian flounder Paralichthys orbignyanus were evaluated. The fish were exposed to 0.12, 0.28 and 0.57mgNH3-NL-1, plus a control, for 10days followed by the same recovery time in ammonia-free water. Gill, liver and muscle samples (n=9) were collected after 1, 5 and 10days of exposure and after recovery for oxidative stress analysis (antioxidant capacity against peroxyl radicals (ACAP); glutathione S-transferase (GST) activity; lipoperoxidation levels measured through thiobarbituric acid reactive substances (TBARS) content). For histological assessment, gill, liver and brain samples were collected. Exposure to all NH3-N concentrations induced different time- and dose-dependent changes in oxidative stress parameters. Reduced antioxidant capacity of the liver and muscle and enhanced TBARS levels in the gills and liver were demonstrated. Differently, a high ammonia concentration elicited lower hepatic TBARS levels. Enhanced GST activity in all organs and increased antioxidant capacity of the gills were also observed. No ammonia-induced histopathological effects were demonstrated. After recovery, most parameters (liver ACAP, GST activity in the muscle and liver and TBARS in the gills) returned to baseline levels. However, liver TBARS and gill GST activity remained altered 0.57mgNH3-NL-1 treatment. The recovery period also led to a decrease in gill antioxidant capacity and an increase in muscle antioxidant capacity. In conclusion, a concentration of 0.12mgNH3-NL-1 induces oxidative stress and antioxidant responses in juvenile Brazilian flounder. Moreover, a 10-day recovery period is not sufficient to restore fish homeostasis.

Taurine mitigates nitrite-induced methemoglobin formation and oxidative damage in human erythrocytes.

Nitrite is present as a noxious contaminant in drinking water and causes oxidative damage in various tissues of humans and animals. It is a well-known methemoglobin-forming agent that has been shown to damage blood cells. The protective effect of taurine, a semi-essential sulfur-containing amino acid, was studied on sodium nitrite (NaNO2)-induced oxidative damage in human erythrocytes. Erythrocytes were incubated with NaNO2, in the presence and absence of taurine, and changes in oxidative stress parameters determined. Pretreatment with taurine significantly ameliorated NaNO2-induced oxidative damage to lipids, proteins, and plasma membrane. It also reduced the NaNO2-induced increase in methemoglobin levels and ROS production. Taurine improved the antioxidant capacity of cells, restored the alterations in the activities of various metabolic enzymes, and prevented morphological changes in erythrocytes. Thus, taurine can be potentially used as a protective agent against the damaging effects of nitrite.

Oxidative Stress Markers in GnRH Agonist and Antagonist Protocols in IVF.

SummaryBackgroundOur aim was to study the effect of GnRH agonist and antagonist protocols of ovarian stimulation on oxidative stress parameters in serum and the influence of oxidative stress parameters change on the outcome of IVF cycles.MethodsThis prospective study included 82 patients who underwent IVF procedures. We determined SOD, MDA and SH groups in serum. Serum samples were obtained between the second and fourth day of the cycle and on the day of HCG administration during ovarian stimulation.ResultsPatients were divided into two groups depending on the protocol of stimulation. The mean total and mature oocytes number and number of fertilized oocytes were higher in GnRH agonist group. There was no significant difference in biochemical pregnancy, miscarriage and live–birth rate in both groups. Mean serum SOD was significantly lower, while mean serum MDA and SH groups were significantly higher after ovarian stimulation. Delivery rate was higher in patients without OS while miscarriage rate was higher in patients with OS.ConclusionsOur study confirmed that there is a difference in the concentration of oxidative stress parameters before and after ovarian stimulation. IVF outcome is better in patients without OS after ovarian stimulation. However, the protocol of ovarian stimulation is neither associated with a change in oxidative stress parameters nor with the outcome of ART procedures.

Neurotoxic responses in brain tissues of rainbow trout exposed to imidacloprid pesticide: Assessment of 8-hydroxy-2-deoxyguanosine activity, oxidative stress and acetylcholinesterase activity

The extensive use of imidacloprid, a neonicotinoid insecticide, causes undesirable toxicity in non-targeted organisms including fish in aquatic environments. We investigated neurotoxic responses by observing 8-hydroxy-2-deoxyguanosine (8-OHdG) activity, oxidative stress and acetylcholinesterase (AChE) activity in rainbow trout brain tissue after 21 days of imidacloprid exposure at levels of (5 mg/L, 10 mg/L, 20 mg/L). The obtained results indicated that 8-OHdG activity did not change in fish exposed to 5 mg/L of imidacloprid, but 10 mg/L and 20 mg/L of imidacloprid significantly increased 8-OHdG activity compared to the control (p < 0.05). An immunopositiv reaction to 8-OHdG was detected in brain tissues. The brain tissues indicated a significant increase in antioxidant enzyme activities (superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx)) compared to the control and there was a significant increase in malondialdehyde (MDA) levels (p < 0.05). High concentrations of imidacloprid caused a significant decrease in AChE enzyme activity (p < 0.05). These results suggested that imidacloprid can be neurotoxic to fish by promoting AChE inhibition, an increase in 8-OHdG activity and changes in oxidative stress parameters. Therefore, these data may reflect one of the molecular pathways that play a role in imidacloprid toxicity.

Alterations in oxidative stress parameters and its associated correlation with clinical disease on experimental Cryptosporidium parvum infection in Swiss albino mice.

The present study was conducted to evaluate the changes in oxidative stress parameters on experimental infection with Cryptosporidium parvum in Swiss albino mice. The mice were divided into four groups viz., group I-IV, each group comprising of 15 mice. Group I mice served as healthy control. In Group II mice, C. parvum oocysts @ 104/os were administered, mice of group III were given dexamethasone @ 30µg/ml in drinking water whereas group IV mice were given dexamethasone @ 30µg/ml along with C. parvum oocysts @ 104/os. Significant changes were seen in oxidative stress parameters which included significant increase in LPO and decrease in levels of SOD, CAT and GSH in liver and intestine in group IV mice at 10th DPI when compared to others indicating an important role played by free radical induced oxidative stress in the development of C. parvum infection in mice which was clinically characterized by loss of body condition, profuse bloody diarrhoea and peak oocyst shedding intensity occurring at 10th DPI.

Crocin protects human erythrocytes from nitrite-induced methemoglobin formation and oxidative damage.

Sodium nitrite (NaNO2 ) is a common contaminant of drinking water and food and feed chain. Nitrite induces oxidative damage in humans and animals. In this work, we studied the protective effect of crocin, the active constituent of Crocus sativus (saffron), on NaNO2 -induced oxidative damage in human erythrocytes. Changes in oxidative stress parameters following NaNO2 incubation of erythrocytes in presence and absence of crocin were determined. It was found that crocin pre-treatment significantly attenuated NaNO2 -induced oxidative damage of proteins, lipids, and plasma membrane. Crocin reduced the level of methemoglobin, the primary acute effect of nitrite intoxication. It also improved the antioxidant capacity of cells and NaNO2 -induced morphological changes in erythrocytes. Crocin is thus a potent protective agent against nitrite-induced cytotoxicity.

Effects of vitamin C on oxidative stress parameters in rainbow trout exposed to diazinon

Abstract: : Diazinon (Organophosphorus insecticide) can cause reactive oxidative stresses during metabolism of aquatic organisms. The study presented here aimed to investigate the antioxidant effect of vitamin C on antioxidant enzyme activities and lipid peroxidation in rainbow trout exposed to subchronic dosage diazinon. A total number of 360 Oncorhynchus mykiss were allocated into four treatment groups (with three replicates): control; diazinon (0.1 mg L 1); vitamin C (300 mg kg 1 in diet) plus diazinon (0.1 mg L-1), and vitamin C (1000 mg kg-1 in diet) plus diazinon (0.1 mg L-1). After two and four weeks, blood samples were collected and superoxide dismutase, catalase enzymes, total antioxidant capacity and malondialdehyte index were measured. The specimens exposed exclusively to diazinon showed a significant decrease in superoxide dismutase and total antioxidant capacity activities and also an increase in catalase activity and malondialdehyde index compared to those of the control group. The changes in oxidative stress parameters may be related to destructive free oxiradicals such as superoxide and hydroxyl radicals produced in diazinon metabolism. In conclusion, vitamin C moderated activity of the antioxidant enzyme, increased the total antioxidant capacity, and decreased cellular damages caused by destructive lipid peroxidation process in presence of diazinon. Keywords: Diazinon, antioxidant, vitamin C, enzyme, malondialdehyde, catalase

Oxidative Stress and Liver Morphology in Experimental Cyclosporine A-Induced Hepatotoxicity.

Cyclosporine A is an immunosuppressive drug used after organ's transplantation. The adverse effects on such organs as kidney or liver may limit its use. Oxidative stress is proposed as one of the mechanisms of organs injury. The study was designed to elucidate CsA-induced changes in liver function, morphology, oxidative stress parameters, and mitochondria in rat's hepatocytes. Male Wistar rats were used: group A (control) receiving physiological saline, group B cyclosporine A in a dose of 15 mg/kg/day subcutaneously, and group C the CsA-vehicle (olive oil). On the 28th day rats were anesthetized. The following biochemical changes were observed in CsA-treated animals: increased levels of ALT, AST, and bilirubin in the serum, statistically significant changes in oxidative stress parameters, and lipid peroxidation products in the liver supernatants: MDA+4HAE, GSH, GSSG, caspase 3 activity, and ADP/ATP, NAD+/NADH, and NADP+/NADPH ratios. Microscopy of the liver revealed congestion, sinusoidal dilatation, and focal hepatocytes necrosis with mononuclear cell infiltration. Electron microscope revealed marked mitochondrial damage. Biochemical studies indicated that CsA treatment impairs liver function and triggers oxidative stress and redox imbalance in rats hepatocytes. Changes of oxidative stress markers parallel with mitochondrial damage suggest that these mechanisms play a crucial role in the course of CsA hepatotoxicity.

Peculiarities of oxidative modification of proteins indices in blood plasma of the female rats’ offspring with experimental gestational diabetes depending on sex, age and basal glycemia level

Analysis of products of oxidative modification of proteins (OMP) in correlation with plasma catalase activity will help us to define the state of oxidative stress parameters in the normal animals and in the female rats’ offspring with experimental gestational diabetes (EGD). Itwilldefine their role in organism’s reorganization aimed to activation of compensatory and defensive mechanisms both at the cellular level and at the level of homeostasis. We’ll also define its alteration in animals with the prenatal negative influence of chronic hyperglycemia.The aim of research wasto study peculiarities of OMP parameters and plasma catalase activity of the female rats’offspring with EGD in dependence on sex, age and basal glycemia level.Materials and methods.The research was carried out on 80 rats (males and females) offspring of the female rats with normal pregnancy and 80 offspring (males and females) of the female rats with EGD. The animals were grouped by the age 2, 4, 6 and 18 months; 20 animals in each group. Animals were freely allowed to standard food and water. When animals reached appropriate age they were decapitated under thiopental anesthesia (40 mg/kg). Glucose was measured by glucose oxidative method in all groups of animals.In order to define the intensity of oxidative reactions in blood plasma of laboratory animals the degree of OMP by Halliwell method was done. Wemeasuredlevelofaldehydephenylhydrazone (APH) which is thought to be as early mark of proteins oxidation, and ketonephenylhydrazone (KPH) which is referred to late mark of protein destruction. The state of antioxidative system was evaluated by plasma catalase activity with the help of spectrophotometric method. The obtained data was processed by statistic programs VIDAS-2.5 (Kontron Elektronik, Германия), EXCEL MS Office 2007 (Microsoft Corp., США), STATISTICA 6.0 (Stat-Soft, 2001).Results and discussion. In the present research, we have observed the decrease of plasma catalase activity with the age both in male and female normal rats. But in female rats catalase activity increases by 12% (pSt&lt;0,05) to senile age, whereas in male rats it remains stable. The decrease of catalase activity is accompanied by increase of APH and KPH concentration (in induced OMP) by 33% (pSt&lt;0,05) and 21% (pSt&lt;0,05) respectively in 4 months old male rats. At the age of 6 months both in males and females content of OMP products – APH and KPH increases.In males APH and KPH in spontaneous OMP increases in 2 times (pSt&lt;0,05) and by 36% (pSt&lt;0,05) respectively; induced OMP caused the increase of KPH by 16% (pSt&lt;0,05). In female rats at the same age APH and KPH increases by 89% (pSt&lt;0,05) and 32% (pSt&lt;0,05) respectively at spontaneous OMP, and by 9% (pSt&lt;0,05) and 47% (pSt&lt;0,05) respectively at induced OMP. At the age of 18 months accumulation of KPH increases by 17% (pSt&lt;0,05) in females and by 27% (pSt&lt;0,05) in males.We established the decrease of plasma catalase activity in offspring of the female rats with EGD in all age groups (both males and females). In the age of 18 months female rats demonstrated 1,8 time decrease (pSt&lt;0,05) of plasma catalase activity; male rats 4-times decrease (pSt&lt;0,05) of it. The “exhaustion” of antioxidative system was accompanied by oxidative destruction of protein molecules, which was manifested with the increase of the parameters of spontaneous and induced oxidative modification of proteins both in male and female rats.Conclusions.The most expressed alterations in the antioxidativesystem are observed in animals, which age corresponds to hormonal rearrangement; they are dependent on intensity of metabolic processes and adaptive abilities of the organism. The most expressed changes of oxidative stress parameters are manifested in male offspring of the female rats with EGD; at the same time alterations in carbohydrate and lipid metabolism develop which progress with the age of the animals.

OP-334 Association between Coronary No-Reflow Phenomenon and Endothelial Nitric Oxide Synthase (Glu298Asp) Gene Polymorphism

The aim of the present study was to demonstrate, through the analysis of novel parameter like PON1, that early changes in oxidative stress takes place in stable coronary artery disease (CAD) patients undergoing elective PCI with implantation of coronary stents. Methods: In this study 32 consecutive chronic stable angina patients (mean age 61 9.8 years, 75% male) undergoing PCI for management of single-vessel CAD (>70% stenosis in a major coronary artery) were included. PON1 enzyme activity were measured immediately before (t1) and just after the procedure (t2), as well as 24 hours later (t3), in order to serially evaluate the changes of oxidative stress parameters in PCI. Results: Baseline demographic, clinical and laboratorycharacteristics of the patients were demonstrated Table 1. When PON1 activities before (t1), immediately after (t2) and 24 hours after (t3) PCI procedurewere compared, a sustained decline was demonstrated (t3 t2 and t3, p 0.05, respectively). There was no correlation between serum PON1 activity and clinical and laboratory parameters of patients. Conclusion: We demonstrated, for the first time, that a substantial impairment of PON1 activity occurs after PCI in patients with stable CAD.We suggest that the PON1 assay may have the potential to be used as an early risk predictor for restenosis in patients undergoing elective PCI with implantation of BMS, a hypothesis which requires further studies.

Changes in oxidative stress parameters and antioxidant status in lung cancer: Western blot analysis of nitrotyrosine and protein carbonyls content.

The source of many diseases, including tumors, lies in an increased generation of reactive oxygen species resulting in oxidative stress. We investigated the relationships between advanced oxidation protein products (AOPPs), nitrotyrosine (NT), protein carbonyls (PCO) content, and the prooxidant-antioxidant balance (PAB) in patients with lung cancer. A total of 14 age-matched healthy controls, 14 subjects with non-lung cancer pulmonary disease, and 41 patients with lung cancer were included in this study. Spectrophotometry was used to examine plasma AOPP, serum FRAP, and PAB, while serum PCO and NT were assessed with western blot analysis. A significant difference in AOPP levels were found between patients and controls (p < 0.01). Also, there was a highly significant difference in NT levels between patients and controls (p < 0.001). PAB showed negative correlation with albumin (r = -0.340, p = 0.011) and positive correlation with CRP (r = 0.342, p = 0.011). AOPP, albumin, gender, and smoking were the significant independent variables found by backward stepwise multiple logistic regression (MLR) analysis method. MLR analysis revealed that AOPP was the variable that had a significant effect on lung cancer [(p = 0.006, OR = 1.074, (95% CI) (1.020-1.131)]. The use of non-invasive diagnostic biochemical parameters would represent a very important contribution to our diagnostic armamentarium in lung cancer, considering the high incidence of this deadly disease. In this regard, AOPP and NT levels have appeared to play a prominent role, although further studies are certainly warranted.

Comparative Effects of Phosphoenolpyruvate, a Glycolytic Intermediate, as an Organ Preservation Agent with Glucose and N-Acetylcysteine against Organ Damage during Cold Storage of Mouse Liver and Kidney

We evaluated the usefulness of phosphoenolpyruvate (PEP), a glycolytic intermediate with antioxidative and energy supplementation potentials, as an organ preservation agent. Using ex vivo mouse liver and kidney of a static cold storage model, we compared the effects of PEP against organ damage and oxidative stress during cold preservation with those of glucose or N-acetylcysteine (NAC). Lactate dehydrogenase (LDH) leakage, histological changes, and oxidative stress parameters (measured as thiobarbituric acid reactive substance and glutathione content) were determined. PEP (100 mM) significantly prevented an increase in LDH leakage, histological changes, such as tubulonecrosis and vacuolization, and changes in oxidative stress parameters during 72 h of cold preservation in mouse liver. Although glucose (100 mM) partly prevented LDH leakage and histological changes, no effects against oxidative stress were observed. By contrast, NAC inhibited oxidative stress in the liver and did not prevent LDH leakage or histological changes. PEP also significantly prevented kidney damage during cold preservation in a dose-dependent manner, and the protective effects were superior to those of glucose and NAC. We suggest that PEP, a functional carbohydrate with organ protective and antioxidative activities, may be useful as an organ preservation agent in clinical transplantation.

069 Advances in shellfish germplasm cryopreservation: Current status and future directions

Cryopreservation can be a powerful tool in shellfish aquaculture for selective breeding programmes and hatchery production. Most species that are commercially farmed are broadcast spawners, releasing sperm and eggs into the environment where they fertilize and develop. However, some species are brooders (e.g. flat oysters (Ostrea chilensis) ), which retain and rear embryos until they reach later developmental stages. Sperm cryopreservation has been successfully achieved for several farmed species including the Pacific oyster ( Crassostrea gigas ), greenshell™ mussel ( Perna canaliculus ) and abalone ( Haliotis iris ). In general, dimethyl sulphoxide and trehalose are the preferred cryoprotectants (CPAs) and simple methods to control cooling rate (e.g. floating rack on liquid nitrogen; methanol/dry ice bath) have worked well for our main species of interest (Pacific oyster, greenshell™ mussel and abalone). Interestingly, sperm perform better in CPAs that are prepared in Milli-Q water as opposed to seawater, indicating that a lower salt concentration during freezing is beneficial. Recent studies with flat oysters and geoducks ( Panopea zelandica ) have also resulted in successful sperm cryopreservation. Shellfish oocyte and larvae cryopreservation has proven more challenging, however, successful cryopreservation of Pacific oyster oocytes has been achieved. Pacific oyster oocytes are able to be fertilized and develop to normal spat post-thawing. However, for other species (e.g. greenshell™ mussel) and for larvae, cryo-injuries are not always immediately apparent post-thawing but manifest during development and are often lethal. greenshell™ mussel oocytes are irretrievably damaged when they reach -6 to -8°C and attempts to overcome this sub-zero chilling injury by vitrification have been unsuccessful. Towards understanding these injuries and their effects, we investigated the effect of cryopreservation on the meiotic spindle of greenshell™ mussel oocytes. Results show that the meiotic spindle undergoes major changes during both CPA addition and cooling. However, the spindle is able to re-form normally in most instances given sufficient time post thawing. For a proportion of oocytes, cryopreservation appears to trigger oocyte activation. The effect of cryopreservation on oxidative stress in greenshell™ mussel oocytes has also been investigated. Although, there are changes in oxidative stress parameters as a result of cryopreservation and strong correlations between fertilization, development and oxidative stress parameters (lipid hydroperoxides, superoxide dismutase, protein carbonyls, total glutathione and glutathione state), preliminary attempts to mitigate oxidative stress using antioxidants have so far failed to enable normal development following cooling, suggesting that oxidative stress may be a secondary rather than primary stress event. Research on shellfish larval cryopreservation utilizing SEM and confocal microscopy has also been carried out for greenshell™ mussel. Later larval stages (D-larvae) appear more resilient to cryopreservation than trochophore larvae, but abnormalities are still apparent (e.g.shell abnormalities and delayed organogenesis). Future studies are aimed toward elucidating mechanisms of injury using new tools such as proteomics and then targeting susceptible cellular processes for protection during cryopreservation. Source of funding: This research was funded by the New Zealand Ministry of Business Innovation and Employment (CAWX0802). Conflict of interest: None declared. serean.adams@cawthron.org.nz

Chronic Cocaine Effects in Retinal Metabolism and Electrophysiology: Treatment with Topiramate

ABSTRACTPurpose: Cocaine abuse is a major public health problem with multiple-related complications. Indeed, cocaine can affect almost every organ of the human body, but little is known about its effects on the visual system. The main purpose of this work was to study if topiramate was able to reverse changes in retinal metabolism and retinal function induced by chronic cocaine exposure in adult rats.Materials and methods: Sixteen Wistar rats were treated with a daily oral dose of cocaine during 36 days. Sixteen rats receiving NaCl 0.9% served as controls. Eight control and eight cocaine animals were administered topiramate from day 18 to day 36 of the experiment. Malondialdehyde (MDA), glutathione (GSH) and glutamate content, as well as glutathione peroxidase (GPx) activity in retina tissue homogenates were determined. Retinal function was assessed by electroretinogram (ERG).Results: Glutamate concentration was increased in the retinas of cocaine-treated rats. No changes in oxidative stress parameters were observed in the retinas of cocaine-treated rats when compared with the control ones. Cocaine induced a decrease in the a-wave and b-wave ERG amplitude. The administration of topiramate reversed cocaine-induced increase in glutamate concentration and had little effect on a-wave and b-wave ERG amplitude. Topiramate, a drug used during the last decade for the treatment of epileptic seizures, is able to reverse the cocaine-induced alterations observed in retinal glutamate concentration.Conclusions: We can conclude that retinal glutamate metabolism and function may be affected by exposure to cocaine. We confirm that topiramate, a treatment recently proposed for cocaine dependence, is also able to recover partially cocaine-induced changes in the retina.

Effect of safeners on damage of human erythrocytes treated with chloroacetamide herbicides

Chloroacetamides are used as pre-emergent substances for growth control of annual grasses and weeds. Since they can be harmful for crop plants, protective compounds (safeners) are used along with herbicides. So far, their effects on human blood cells have not been evaluated, and this study is the very first one devoted to this subject.We examined the harmful effects of chloroacetamides, their metabolites and safeners, used alone or in combination with herbicides, on human erythrocytes measuring the extent of hemolysis, lipid peroxidation and catalase activity. Higher impact of herbicides than their metabolites on all of the investigated parameters was found. Safeners alone did not produce any damage to erythrocytes and did not elicit any changes in oxidative stress parameters. Combination of safener with herbicide did not attenuate hemolysis of erythrocytes compared to the herbicide alone. Safeners reduced lipid peroxidation induced by herbicides, which suggest the role of safeners as antioxidants.

Phosphoenolpyruvate, a glycolytic intermediate, as a cytoprotectant and antioxidant in ex-vivo cold-preserved mouse liver: a potential application for organ preservation

The aim of this study was to examine the effect of phosphoenolpyruvate (PEP), a glycolytic intermediate, on organ damage during cold preservation of liver. An ex-vivo mouse liver cold-preservation model and an in-vitro liver injury model induced by hydrogen peroxide in HepG2 cells were leveraged. PEP attenuated the elevation of aminotransferases and lactate dehydrogenase leakage during organ preservation, histological changes and changes in oxidative stress parameters (measured as thiobarbituric acid reactive substance and glutathione content) induced by 72 h of cold preservation of the liver. The effects were comparable with the University of Wisconsin solution, a gold standard organ preservation agent. The decrease in ATP content in liver during the cold preservation was attenuated by PEP treatment. PEP prevented the cellular injury and increases in intracellular reactive oxygen species in HepG2 cells. In addition, PEP scavenged hydroxyl radicals, but had no effect on superoxide anion as evaluated by an electron paramagnetic resonance spin-trapping technique. PEP significantly attenuated the injury, oxidative stress and ATP depletion in liver during cold preservation. The antioxidative potential of PEP was confirmed by in-vitro examination. We suggest that PEP acts as a glycolytic intermediate and antioxidant, and is particularly useful as an organ preservation agent in clinical transplantation.