Maria Cristina Munteanu

An inter-laboratory validation of methods of lipid peroxidation measurement in UVA-treated human plasma samples

Abstract Lipid peroxidation products like malondialdehyde, 4-hydroxynonenal and F2-isoprostanes are widely used as markers of oxidative stress in vitro and in vivo. This study reports the results of a multi-laboratory validation study by COST Action B35 to assess inter-laboratory and intra-laboratory variation in the measurement of lipid peroxidation. Human plasma samples were exposed to UVA irradiation at different doses (0, 15 J, 20 J), encoded and shipped to 15 laboratories, where analyses of malondialdehyde, 4-hydroxynonenal and isoprostanes were conducted. The results demonstrate a low within-day-variation and a good correlation of results observed on two different days. However, high coefficients of variation were observed between the laboratories. Malondialdehyde determined by HPLC was found to be the most sensitive and reproducible lipid peroxidation product in plasma upon UVA treatment. It is concluded that measurement of malondialdehyde by HPLC has good analytical validity for inter-laboratory studies on lipid peroxidation in human EDTA-plasma samples, although it is acknowledged that this may not translate to biological validity.

Adapted response of the antioxidant defense system to oxidative stress induced by deoxynivalenol in Hek-293 cells

The mycotoxin deoxynivalenol (DON), a contaminant of certain foods and feeds, is cytotoxic and genotoxic to mammalians cells. Exposure of human embryonic kidney (Hek-293) cells to DON led to a dose- and time-dependent decrease in cell viability, with an IC(50) about 7.6 μM. The DON effects on Hek-293 morphology, reactive oxygen species, lipid peroxidation and antioxidative system and caspase 3 and bcl-2 expression were studied. Cells became round and in some are progressive loss of cell attachment appeared. These biochemical parameters were assessed after 6, 12 and 24 h of treatment with 2.5 and 5 μM DON. An increase in superoxide dismutase activity within the interval 6-12 h and almost complete recovery by the end of experiment for both concentrations was observed, whereas the profile of catalase activity was the same with the superoxide dismutase one for 2.5 μM and decreased in a time-dependent manner for 5 μM. A temporary activation of glutathione peroxidase and glutathione reductase was recorded at 12 h post-exposure, while the glutathione-S-transferase activity was unchanged for both concentrations. The NADP(+)-dependent isocitrate dehydrogenase activity showed a transient increase at the 12 h post-exposure. The caspase 3 expression remained unchanged and the bcl-2 one decreased after 24 h of exposure for the two concentrations. Our results showed the dose- and time specific changes in the antioxidants system of Hek-293 cells, which could not counteract efficiently the effects DON exposure. The different types of cell death which could be activated by this DON induced changes are mentioned.

Malathion-induced alteration of the antioxidant defence system in kidney, gill, and intestine of Carassius auratus gibelio

Pesticides such as malathion, commonly used in agriculture and households, are toxic substances that lead to reactive oxygen species generation, which harms organisms. Ecotoxicological consequences of malathion, particularly its effects on antioxidants in fish, are not well understood. Thus, we investigated the effects of malathion (0.05 mg/L) on lipid peroxidation and antioxidant systems in Carassius auratus gibelio kidney, intestine, and gills following exposure times of 1, 2, 3, and 6 days. The lipid peroxidation and antioxidative defense mechanisms display different responses in investigated tissues. The lipid peroxidation was increased in all investigated tissues, especially after 1 day of malathion administration. Changes in reduced glutathione levels have been registered, mainly after 6 days of pesticide exposure. The modulation in the activities of antioxidant enzymes, catalase, gluthatione peroxidase, glutathione reductase, and glutathione‐S‐transferase was time and tissue specific. The investigated parameters can be used as biomarkers of fish exposure to malathion.

Extracellular matrix is modulated in advanced glycation end products milieu via a RAGE receptor dependent pathway boosted by transforming growth factor-β1 RAGE.

Interstitial fibrosis is induced by imbalances in extracellular matrix homeostasis. Advanced glycation end products (AGEs) can bind and activate the receptor for AGEs (RAGE), which is involved in diabetic nephropathy. We set out to identify the role of AGEs in producing alterations leading to matrix hypertrophy and the pathway through which aminoguanidine, as well as anti‐RAGE and anti‐transforming growth factor (TGF)‐β1 antibody treatments could prevent these modifications.

Interaction of silicon-based quantum dots with gibel carp liver: oxidative and structural modifications

Quantum dots (QDs) interaction with living organisms is of central interest due to their various biological and medical applications. One of the most important mechanisms proposed for various silicon nanoparticle-mediated toxicity is oxidative stress. We investigated the basic processes of cellular damage by oxidative stress and tissue injury following QD accumulation in the gibel carp liver after intraperitoneal injection of a single dose of 2 mg/kg body weight Si/SiO2 QDs after 1, 3, and 7 days from their administration.QDs gradual accumulation was highlighted by fluorescence microscopy, and subsequent histological changes in the hepatic tissue were noted. After 1 and 3 days, QD-treated fish showed an increased number of macrophage clusters and fibrosis, while hepatocyte basophilia and isolated hepatolytic microlesions were observed only after substantial QDs accumulation in the liver parenchyma, at 7 days after IP injection.Induction of oxidative stress in fish liver was revealed by the formation of malondialdehyde and advanced oxidation protein products, as well as a decrease in protein thiol groups and reduced glutathione levels. The liver enzymatic antioxidant defense was modulated to maintain the redox status in response to the changes initiated by Si/SiO2 QDs. So, catalase and glutathione peroxidase activities were upregulated starting from the first day after injection, while the activity of superoxide dismutase increased only after 7 days. The oxidative damage that still occurred may impair the activity of more sensitive enzymes. A significant inhibition in glucose-6-phosphate dehydrogenase and glutathione-S-transferase activity was noted, while glutathione reductase remained unaltered.Taking into account that the reduced glutathione level had a deep decline and the level of lipid peroxidation products remained highly increased in the time interval we studied, it appears that the liver antioxidant defense of Carassius gibelio does not counteract the oxidative stress induced 7 days after silicon-based QDs exposure in an efficient manner.

Structural and Oxidative Changes in the Kidney of Crucian Carp Induced by Silicon-Based Quantum Dots

Silicon-based quantum dots were intraperitoneally injected in Carassius auratus gibelio specimens and, over one week, the effects on renal tissue were investigated by following their distribution and histological effects, as well as antioxidative system modifications. After three and seven days, detached epithelial cells from the basal lamina, dilated tubules and debris in the lumen of tubules were observed. At day 7, nephrogenesis was noticed. The reduced glutathione (GSH) concentration decreased in the first three days and started to rise later on. The superoxide dismutase (SOD) activity increased only after one week, whereas catalase (CAT) was up-regulated in a time-dependent manner. The activities of glutathione reductase (GR) and glutathione peroxidise (GPX) decreased dramatically by approximately 50% compared to control, whereas the glutathione-S-transferase (GST) and glucose-6-phosphate dehydrogenase (G6PDH) increased significantly after 3 and 7 days of treatment. Oxidative modifications of proteins and the time-dependent increase of Hsp70 expression were also registered. Our data suggest that silicon-based quantum dots induced oxidative stress followed by structural damages. However, renal tissue is capable of restoring its integrity by nephron development.

Extracellular matrix is modulated in advanced glycation end products milieu via a RAGE receptor dependent pathway boosted by transforming growth factor‐β1 在晚期糖基化终末产物环境中细胞外基质通过RAGE受体依赖性途径调节，转化生长因子‐β1可以促进这种调节

Interstitial fibrosis is induced by imbalances in extracellular matrix homeostasis. Advanced glycation end products (AGEs) can bind and activate the receptor for AGEs (RAGE), which is involved in diabetic nephropathy. We set out to identify the role of AGEs in producing alterations leading to matrix hypertrophy and the pathway through which aminoguanidine, as well as anti‐RAGE and anti‐transforming growth factor (TGF)‐β1 antibody treatments could prevent these modifications.

Extracellular matrix is modulated in advanced glycation end products milieu via a RAGE receptor dependent pathway boosted by transforming growth factor-β1 在晚期糖基化终末产物环境中细胞外基质通过RAGE受体依赖性途径调节，转化生长因子-β1可以促进这种调节: AG and antibodies exposure outcome in AGEs milieu

Interstitial fibrosis is induced by imbalances in extracellular matrix homeostasis. Advanced glycation end products (AGEs) can bind and activate the receptor for AGEs (RAGE), which is involved in diabetic nephropathy. We set out to identify the role of AGEs in producing alterations leading to matrix hypertrophy and the pathway through which aminoguanidine, as well as anti‐RAGE and anti‐transforming growth factor (TGF)‐β1 antibody treatments could prevent these modifications.

Bioactive ceramic glasses in situ synthesized by laser melting

The synthesis of bioactive glass from raw materials even during the laser deposition process, could provide formation of a biocompatible layer on the metallic prosthesis. During the laser irradiation melting and ultrarapid solidification of ceramic materials occur and glasses controlled by the process parameters (especially laser power and solidification rate) will be obtained. The aim of the present paper is to study the influence of the processing parameters on the laser synthesized glasses chemical composition, structure and bioactive behaviour.