Hydrogen peroxide induces adaptive response and differential gene expression in human embryo lung fibroblast cells

Kurarinone attenuates hydrogen peroxide-induced oxidative stress and apoptosis through activating the PI3K/Akt signaling by upregulating IGF1 expression in human ovarian granulosa cells

Dysregulated follicular development may lead to follicular atresia, and this is associated with oxidative stress in granulosa cells. Kurarinone is a natural compound possessing multiple activities, including antioxidative ability. However, the role of kurarinone in granulosa cell damage during follicular atresia remains unknown. Human ovarian granulosa KGN cells were treated with hydrogen peroxide (H₂ O₂ ) to induce cellular damage. Cytotoxicity was investigated by lactate dehydrogenase (LDH) release assay. Oxidative stress was evaluated by detection of reactive oxygen species (ROS) generation and oxidative biomarker levels. Cell apoptosis was evaluated by flow cytometry, a Cell Death Detection ELISA Kit, and a Caspase-3 Assay Kit. The downstream target and related signaling pathway were analyzed by western blotting. Kurarinone attenuated H₂ O₂ -induced LDH release in KGN cells. Kurarinone relieved H₂ O₂ -induced increase in ROS generation and malondialdehyde level as well as decrease in superoxide dismutase-1 activity and heme oxygenase 1 and NAD(P)H quinone dehydrogenase 1 mRNA levels. Kurarinone inhibited H₂ O₂ -induced apoptosis in KGN cells. Kurarinone targeted insulin-like growth factor 1 (IGF1) and upregulated IGF1 expression to activate the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signaling. IGF1 silencing attenuated the suppressive effects of kurarinone on H₂ O₂ -induced oxidative stress and apoptosis in KGN cells. In conclusion, kurarinone attenuates H₂ O₂ -induced oxidative stress and apoptosis in KGN cells through activating the PI3K/Akt signaling by upregulating IGF1 expression, indicating the therapeutic potential of kurarinone in follicular atresia.

Effects of Size-Fractionated Particulate Matter on Cellular Oxidant Radical Generation in Human Bronchial Epithelial BEAS-2B Cells

The aim of the present study was to investigate the effects of size-fractionated (i.e., <1; 1-2.5, and 2.5-10 µm in an aerodynamic diameter) ambient particulate matter (PM) on reactive oxygen species (ROS) activity and cell viability in human bronchial epithelial cells (BEAS-2B). The PM samples were collected from an urban site (uPM) in Beijing and a steel factory site (sPM) in Anshan, China, from March 2013 to December 2014. Metal elements, organic and elemental carbon, and water-soluble inorganic ions in the uPM and sPM were analyzed. The cell viability and ROS generation in PM-exposed BEAS-2B cells were measured by MTS and DCFH-DA. The results showed that both uPM and sPM caused a decrease in the cell viability and an increase in ROS generation. The level of ROS measured in sPM1.0 was approximately triple that in uPM1.0. The results of correlation analysis showed that the ROS activity and cytotoxicity were related to different PM composition. Moreover, deferoxamine (DFO) significantly prevented the increase of ROS generation and the decrease of cell viability. Taken together, our results suggest that the metals absorbed on PM induced oxidant radical generation in BEAS-2B cells that could lead to impairment of pulmonary function.

Long Chain Fatty Acid Esters of Quercetin-3-O-glucoside Attenuate H₂O₂-induced Acute Cytotoxicity in Human Lung Fibroblasts and Primary Hepatocytes

Cellular oxidative stress causes detrimental effects to macromolecules, such as lipids, nucleic acids and proteins, leading to many pathological conditions. Quercetin-3-O-glucoside (Q3G), a glycosylated derivative of quercetin (Q), is a natural polyphenolic compound known to possess antioxidant activity. The hydrophilic/lipophilic nature of an antioxidant molecule is considered as an important factor governing the accessibility to the active sites of oxidative damages in vivo. Six long chain fatty acid esters of Q3G were evaluated with comparison to Q and Q3G, for their cytoprotective activity under H₂O₂-induced oxidative stress using cell culture model systems through cell viability, lipid peroxidation and fluorescence microscopy studies. Pre-incubation of α-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) esters of Q3G exhibited significantly (p ≤ 0.05) greater cell viability in both human lung fibroblast (WI-38) and human primary hepatocytes upon exposure to H₂O₂ insult when compared to the control. Cytoprotection due to oleic acid and linoleic acid esters of Q3G was observed only in human primary hepatocytes. All the derivatives, Q3G and quercetin showed ability to significantly (p ≤ 0.05) lower production of lipid hydroperoxides under induced oxidative stress, compared to the control. However, ALA and DHA esters of Q3G resulted in significantly lower lipid hydroperoxidation than Q and Q3G. Based on fluorescence microscopy study, H₂O₂-induced apoptosis was attenuated by the fatty acid derivatives of Q3G. The fatty acid derivatives of Q3G possess better cytoprotective effect than Q3G against H₂O₂-induced cytotoxicity in vitro and the concentration should be selected to avoid cytotoxicity.

Hydrogen peroxide induced by modulated electromagnetic radiation protects the cells from DNA damage

It is believed that non-ionizing electromagnetic radiation (EMR) and low-level hydrogen peroxide (H2O2) may change nonspecific resistance and modify DNA damage caused by ionizing radiation. To check this assumption, the combined effects of extremely high-frequency EMR (EHF EMR) and X-rays on induction of DNA damage in mouse whole blood leukocytes were studied. The cells were exposed to X-rays with or without preliminary treatment with EHF EMR or low-level H2O2. With the use of enhanced chemiluminescence, it was shown for the first time that pulse-modulated EHF EMR (42.2 GHz, incident power density of 0.1 mW/cm2, exposure duration of 20 min, modulation frequency of 1 Hz) induced H2O2 at a concentration of 4.6 ± 0.3 nM L−1 in physiological saline. With the use of an alkaline comet assay, it was found that the exposure of cells to the pulse-modulated EHF EMR, 25 min prior to treatment with X-rays at a dose of 4 Gy reduced the level of ionizing radiation-induced DNA damage. Continuous EHF EMR was inefficient. In turn, it was shown that low-level H2O2 (30–500 nM L−1) protected the cells against X-irradiation. Thus, the mechanisms of radiation protective effect of EHF EMR are connected with the induction of the adaptive response by nanomolar concentrations of reactive oxygen species formed by pulse-modulated EHF EMR.