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Background

Exposure to high altitude in hypobaric hypoxia (HH) is considered to be a physiological oxidative/nitrosative stress. Quercetin (Que) is an effective antioxidant and free radical scavenger against oxidative/nitrosative stress.

Aims

The aim of this study was to investigate the cardioprotective effects of Que in animals exposed to intermittent HH (IHH) and therefore exposed to oxidative/nitrosative stress.

Materials and methods

Wistar albino male rats were exposed to short-term (2 days) or long-term (4 weeks; 5 days/week) IHH in a hypobaric chamber (5,500 m, 8 h/day, 380 mmHg, 12% O2, and 88% N2). Half of the animals received natural antioxidant Que (body weight: 30 mg/kg) daily before each IHH exposure and the remaining rats received vehicle (carboxymethylcellulose solution). Control rats were kept under normobaric normoxia (Nx) and treated in a corresponding manner. One day after the last exposure to IHH, we measured the cardiac hypoxia-induced oxidative/nitrosative stress biomarkers: the malondialdehyde (MDA) level and protein carbonyl (PC) content, the activity of some antioxidant enzymes [superoxide dismutase (SOD) and catalase (CAT)], the nitrite plus nitrate (NOx) production, and the inducible nitric oxide synthase (iNOS) protein expression.

Results

Heart tissue MDA and PC levels, NOx level, and iNOS expression of IHH-exposed rats had increased, and SOD and CAT activities had decreased compared with those of the Nx-exposed rats (control groups). MDA, CP, NOx, and iNOS levels had decreased in Que-treated IHH-exposed rats compared with IHH-exposed rats (control groups). However, Que administration increased SOD and CAT activities of the heart tissue in the IHH-exposed rats.

Conclusion

HH exposure increases oxidative/nitrosative stress in heart tissue and Que is an effective cardioprotective agent, which further supports the oxidative cardiac dysfunction induced by hypoxia.

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Background

To investigate the protective effects of Quercetin administration associated with chronic moderate exercise (training) on oxidative stress in the liver in streptozotocin-induced diabetic rats.

Methods

Diabetic rats that performed exercise training were subjected to a swimming training program (1 hour/day, 5 days/week, 4 weeks). The diabetic rats received natural antioxidant, Quercetin (20 mg/kg body weight/day) for 4 weeks. At the end of the study, all animals were sacrificed and liver samples were collected for estimation: some oxidative stress markers (malondialdehyde, MDA and protein carbonyls groups, PC), the activity of antioxidant enzymes (superoxide dismutase, SOD and catalase, CAT), reduced glutathione (GSH) level and reduced (GSH) and oxidized (GSSG) glutathione ratio.

Results

Diabetic rats submitted to exercise training showed significantly increased the oxidative stress markers (MDA and PC) and a reduction of antioxidant enzyme (SOD and CAT) activity, GSH level and GSH/ GSSG ratio in hepatic tissues. A decrease in the levels of oxidative stress markers associated with elevated activity of antioxidant enzymes, the GSH level and GSH/GSSG ratio in the hepatic tissue were observed in Quercetin-treated diabetic trained rats.

Conclusions

These findings suggest that Quercetin administration in association with chronic moderate exercise exerts a protective effect in diabetes by attenuating hyperglycemia-mediated oxidative stress in hepatic tissue.

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Authors: Simona Clichici, T. Mocan, A. Filip, A. Biris, S. Simon, D. Daicoviciu, N. Decea, A. Parvu, R. Moldovan and A. Muresan

Single-walled carbon nanotubes (SWCNTs) have been proposed for various medical applications. However, their safety for human administration has not been yet fully demonstrated. In vitro studies have pointed oxidative stress as a mechanism involved in their cytotoxic effects. In the present study we have evaluated the capacity of DNA functionalized SWCNTs to induce oxidative stress in blood after intraperitoneal (ip) administration in rats. The presence of SWCNTs in blood was confirmed by Raman spectroscopy 30 minutes after their ip administration. Oxidative stress parameters (malondialdehyde — MDA, protein carbonyls — PC, antioxidant capacity measured as hydrogen donating capacity — HD, sulfhydryl groups — SH, glutathione — GSH and nitrites — NO) were assessed in blood at 3, 6, 24, respectively, and 48 hours after ip injection. MDA, PC and NO exhibited a significant increase at 3-6 hours interval from exposure, followed by a recovery trend. The levels of HD reached a bottom level at 6 hours after administration, while SH strongly decreased at 3 hours interval and increased slightly up to 48 hours without attending the initial values. GSH level recorded an increasing tendency at the 3rd hour, an incomplete recovery process at 24 hours followed by a secondary significant increase following a 48-hour interval. Significant inverse correlations were obtained between the PC and SH levels and between the NO and HD values. In conclusion, the ip administration of DNA functionalized SWCNT in rats results in oxidative stress generation in plasma, with a transient pattern of evolution.

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Authors: L. E. Muresan, E.-J. Popovici, E. Bica, A. I. Cadis, I. Perhaita and L. Barbu Tudoran

Abstract

Three types of precursors were prepared using the wet-chemical synthesis route, starting from yttrium–europium–aluminum nitrate solution and different precipitating agents (urea, oxalic acid, and ammonium carbonate). The precursors were fired at 1200 °C in nitrogen atmosphere in order to obtain europium-doped yttrium aluminate Y3Al5O12:Eu3+ phosphor with garnet structure (YAG:Eu). The processes involved in the thermal decomposition of precursors and their composition were put in evidence using thermal analysis (TG–DTA) and FT-IR spectroscopy. The GA–DTA curves possess typical features for basic-oxalate, -nitrate, and -carbonates as formed with oxalic acid, urea, and ammonium carbonate, respectively. Correlation between the thermal decomposition steps, mass loss, and composition of gases evolved during the thermal treatment was established using TG–DTA–FT-IR coupling. It was found that the different composition of precursors reflects on the luminescent characteristics of the corresponding phosphors. Urea and ammonium carbonate lead to the formation of YAG type phosphors, with garnet structure and specific red emission. As for the oxalic acid, this precipitating agent generates a non-homogeneous powder that contains yttrium oxide as impurity phase. This phosphor is a mixture of Y2O3:Eu3+, Y4Al2O9:Eu3+, and Y3Al5O12:Eu3+ that explain the relative higher emission intensity.

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Authors: Adriana Mureşan, C. Alb, S. Suciu, S. Clichici, A. Filip, C. Login, N. Decea and T. Mocan

To estimate the effects of hydroethanolic red grapes seeds extract obtained from Vitis vinifera, Burgund Mare variety, Recaş , Romania (BMR) on oxidant-antioxidant ballance, as compared to ascorbic acid, during pregnancy in rats. Thirty Wistar female rats were assigned to three groups (n=10) which were administered by gavage: Group I, 3 × 100 mg/kg body weight saline, Group II — BMR 3 × 30 mg gallic acid equivalents/kg body weight; Group III — vitamin C 3 × 100 mg/kg body weight on days 1, 7 and 14 of pregnancy. On day 21 blood samples were collected. Malon dyaldehyde, lipid peroxides, protein carbonyls, nitric oxide (as oxidative stress parameters) and hydrogen donor ability and total thiol groups (as antioxidant parameters) serum concentrations were measured. Vitamin C significantly enhanced the antioxidant capacity of plasma (hydrogen donor ability, p=0.0001; thiol groups, p=0.0001), as well as nitric oxide levels (p=0.001). The extract increased the plasma antioxidant capacity (hydrogen donor ability, p=0.001; thiol groups p=0.001) and did not elevate the nitric oxide plasma levels in pregnant rats.In conclusion, in the chosen dose, the red grapes seed extract enhanced the plasma antioxidant capacity and did not influence the nitric oxide levels in pregnant rats.

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Authors: Diana Olteanu, A. Filip, A. Mureşan, A. Nagy, F. Tabaran, R. Moldovan, N. Decea, C. Catoi and S. Clichici

Inflammation and oxidative stress are important pathways in the development of liver fibrosis following biliary obstruction.Aim: To evaluate the effects of low dose dexamethasone and chitosan, a natural compound with no side-effects, on liver damage caused by bile duct ligation in rats.Materials and methods: Fifty female Wistar rats, randomly and equally divided in 5 groups: I (SHAM) underwent only laparotomy, II (BDL) with bile duct ligation, III (DEX) 0.125 mg/kg dexamethasone i.m. daily, IV (CS) 1 mg/kg chitosan by gavage and group V (DEX+CS), both substances. After six days, the following parameters were assessed from liver homogenates: malondialdehyde (MDA), protein carbonyls (PC), reduced glutathione (GSH), total SH groupings, nitric oxide (NO), and from plasma: MDA, γ-glutamyltranspeptidase (GGT), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and total bilirubin (TB). A histopathological examination was performed using some of the elements of the Knodell Histological Activity Index.Results: BDL significantly increases the levels of MDA, liver enzymes, and the necro-inflammatory score compared to the sham group and it decreases the antioxidant capacity. DEX protects against lipid peroxidation and improves the antioxidant capacity, but it is not able to protect the hepatocytes. Chitosan significantly decreases (p<0.05) the levels of MDA (0.07±0.01 vs 0.10±0.01 nmoles/mg protein BDL group, p=0.027) and also ALT, TB, GGT and reduces liver necrosis and inflammation (2.75±0.95 vs 1±0, p<0.05). Both CS and DEX reduce the level of NO significantly.Conclusion: BDL induces severe oxidative stress damage after six days already. Chitosan proved very efficient in protecting the hepatocytes against oxidative stress, a fact supported by the histological findings.

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Authors: S. Maghraoui, Simona Clichici, A. Ayadi, C. Login, R. Moldovan, D. Daicoviciu, N. Decea, A. Mureşan and L. Tekaya

Aluminum (Al) and indium (In) have embryotoxic, neurotoxic and genotoxic effects, oxidative stress being one of the possible mechanisms involved in their cytotoxicity. We have recently demonstrated that indium intraperitoneal (ip) administration induced histological disorganization of testicular tissue. In the present research we aimed at investigating the effect of Al and In ip administration on systemic and testicular oxidative stress status. Studies were performed on Wistar rats ip injected with Al, In or physiological solution for two weeks. Our results showed that In significantly decreased the absolute weight of testicles. Measurements of lactate dehydrogenase (LDH) and paraoxonase (PON) activities showed that In induced a significant augmentation in the first parameter but no changes were observed in the second. Both Al and In caused oxidative stress in testicles by increasing malondialdehyde (MDA) and protein carbonyls (PC) production. Concomitantly, thiol group (—SH) and glutathione (GSH) level were enhanced in the testicles. In the blood, while concentrations of MDA was not changed, those of GSH was significantly decreased in the Al and In groups. Our results indicated that Al and In cause oxidative stress both in blood and testicles but In has cytotoxic effect as well as negative impact on testicle weights. These findings could explain the testicular histological alterations previously described after In ip administration.

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Authors: Simona Clichici, A. Filip, D. Daicoviciu, R. Ion, T. Mocan, C. Tatomir, L. Rogojan, D. Olteanu and A. Muresan

Photodynamic therapy (PDT) is a promising therapy especially in skin cancer, using the systemic administration of a photosensitizer (PS), followed by the local irradiation of the tumor with visible light. The antitumor effects of PDT are determined especially by the generation of cytotoxic reactive oxygen species (ROS). The 5,10,15,20-tetrasulfophenyl-porphyrin (TSPP) is a synthetic photosensitizer, which proved its efficiency in in vitro studies. Our study evaluates the effects of PDT with TSPP upon the tumor levels of ROS and upon the metalloproteinases 2 (MMP2) activities on Wistar male rats bearing 256 Walker carcinosarcoma in correlation with the accumulation of PS in the tumor and with the intratumor histological alterations. The evaluations were performed dynamically, at 3 hours, 6 hours, 24 hours and 14 days after the PDT with TSPP. Our results emphasize that 24 hours after the PDT with TSPP, the ROS generation increases, as revealed by protein carbonyls and malondialdehyde levels and the antioxidant capacity (hydrogen donors, thiol groups) decreases in the tumor tissue. These parameters were correlated with the appearance of the histological disorders. The MMP-2 activity increases exponentially in the 24 hours — 14 days post PDT interval. PDT with TSPP offers, in vivo, consistent results regarding ROS generation, MMP2 activation and cytotoxic capacity.

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Authors: Teodora Mocan, S. Clichici, L. Agoşton-Coldea, L. Mocan, Ş Şimon, I. Ilie, A. Biriş and Adriana Mureşan

Nanosized particles (NPs) have recently been proposed for extensive use, including into the biomedical field. As a result, research on toxicity and oxidative stress concerning the interaction of nanoparticle and the living organism has attracted increasing interest among specialists. Two different targets have been the motor of this type of research: 1) the safety concern regarding such NPs large-scale use along with the need to generate antidote solutions to possible adverse effects, 2) the idea of influencing oxidative damage and of using them for elaborating anticancer/antimicrobial therapies. Present study reviews recent research achievements within the proposed theme taking into account the nature and particularities of each type of nanoparticle.

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The lactic acid bacteria are key microorganisms for the production and preservation of fermented dairy products, cheeses, sourdough bread, and lacto-fermented vegetables. This study was developed to monitor lactic acid produced by Lactobacillus plantarum ATCC 8014 and Lactobacillus casei ATCC 393, as single strains and combined, in fermenting media by Fourier Transform Infrared Spectroscopy coupled to multivariate statistical analysis. Media containing different mixtures of carbohydrates were chosen as model fermenting media for monitoring lactic acid concentration by infrared spectroscopy, due to the fact that vegetable and animal food matrices could contain different carbohydrates as carbon sources. Three different types of media were obtained by adding different carbohydrates to a basic MRS medium. HPLC was used as reference method for lactic acid quantification. The calibration set (n=36) was used for building model, while a validation set (n=13) for testing the robustness of the developed model. The coefficients of determination between predicted and reference values were 0.986 and 0.965, while root mean square error for calibration and validation sets recorded values of 0.127 and 0.263 g·l−1, respectively. Results confirmed the efficiency of FTIR spectroscopy combined with multivariate statistics, as a rapid, reliable, and cost-effective tool for routine monitoring of lactic acid.

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