Oxidative Stress Injury Model Research Articles

Icariin attenuated oxidative stress induced-cardiac apoptosis by mitochondria protection and ERK activation.

Our previous study showed that Icariin (ICA) has anti-cardiac hypertrophy effect in rats with an unknown mechanism. In the present study, we aimed to clarify the cardiac protective effect and mechanism of ICA in vitro. H9C2 cardiac myocytes were incubated with H2O2 to build up the oxidative stress injury model. The results showed that pre-treatment of ICA protected cells against the toxicity induced by H2O2. H2O2 treatment significantly reduced H2O2-induced apoptosis, evidenced by lower Annexin V/PI stained cells and less PARP and caspase-3/9 activation. Mitochondria membrane potential (MMP) dissipation occurred following the exposure of H2O2, which could be prevented by ICA treatment. Moreover, Ca2+ homeostasis was preserved by ICA and ROS generation was significantly suppressed by ICA incubation. Interestingly, ICA treatment increased the phosphorylation of upstream ERK mitogen-activated protein kinase (MAPK) while ERK inhibitor U1026 could reverse the protective effect of ICA. Overall, ICA seems to protect the cardiac cells from oxidative stress injury through ROS scavenge and stimulation of ERK pathway which may explain its effects in vivo.

Tanshinone IIA protects H9c2 cells from oxidative stress-induced cell death via microRNA-133 upregulation and Akt activation.

The aim of the present study was to investigate the cardioprotective effect of tanshinone IIA and the underlying molecular mechanisms. An in vitro model of oxidative stress injury was established in cardiac H9c2 cells, and the effects of tanshinone IIa were investigated using cell viability, reverse transcription-quantitative polymerase chain reaction and western blotting assays. The results demonstrated that tanshinone IIA protects H9c2 cells from H2O2-induced cell death in a concentration-dependent manner, via a mechanism involving microRNA-133 (miR-133), and that treatment with TIIA alone exerted no cytotoxic effects on H9c2. In order to further elucidate the mechanisms underlying the actions of TIIA, reverse transcription-quantitative polymease chain reaction and western blot analysis were performed. Reductions in miR-133 expression levels induced by increasing concentrations of H2O2 were reversed by treatment with tanshinone IIA. In addition, the inhibition of miR-133 by transfection with an miR-133 inhibitor abolished the cardioprotective effects of tanshinone IIA against H2O2-induced cell death. Furthermore, western blot analysis demonstrated that tanshinone IIA activated Akt kinase via the phosphorylation of serine 473. Inhibition of the phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway by pretreatment with the PI3K specific inhibitors wortmannin and LY294002 also eliminated the cardioprotective effects of tanshinone IIA against H2O2-induced cell death. Western blot analysis demonstrated that H2O2-induced reductions in B cell lymphoma 2 (Bcl-2) expression levels were reversed by tanshinone IIA. In addition, the effect of tanshinone IIA on Bcl-2 protein expression level in an oxidative environment was suppressed by a PI3K inhibitor, wortmannin, indicating that tanshinone IIA exerts cardioprotective effects against H2O2-induced cell death via the activation of the PI3K/Akt signal transduction pathway and the consequent upregulation of Bcl-2. In conclusion, the present study demonstrates that TIIA is able to protcet H9c2 cells from oxidative stress-induced cell death through signalling pathways involving miR-133 and Akt, and that tanshinone IIA is a promising natural cardioprotective agent.

Establishment and evaluation of oxidative stress injury model of in vitro rat aortic endothelial cells

To establish a model of oxidative stress injury in cultured rat aortic endothelial cells, and to provide a basis for the research of cell injury and apoptosis. The rats were decapitated to get the aorta in thoracic operation under aseptic conditions. By subculture after tissue block culture method to get sufficient aortic endothelial cells, cultured in 96-well plates or grow on cover glass for the following test. Without H2O2 group as a control group, with different doses of H2O2 (100,200,300,400,500 μmol/L) treated endothelialcells in 12 h to screen the optimal dose. Based on the results, with the same dose of H2O2 (100 or 200 μmol/L) acted on endothelial cells respectively in different time (3, 6, 9, 12 and 24 h) to screen the optimal duration. Each group was made in sextuplicate. The establishment of the model was evaluated by immunofluorescence,cell viability testing, biochemical indicators detection (lactate dehydrogenase(LDH), nitric oxide(NO), malondialdehyde(MDA), superoxidedismutase(SOD))and apoptosis index testing. Endothelial cells were cultured successfully and verified by immunofluorescence staining of intracellular antigen Ⅷ collagen. With the increase of H2O2 doses at the same action time 12 h, the cell viability was significantly decreased (77.63%±5.20% to 40.90%±2.10%). The same dose(100 μmol/L group and 200 μmol/L group)with the action time increasing, the cellviability was significantly decreased (100 μmol/L group was 86.83%±12.11% to 44.26%±5.70%, 200 μmol/L group was 78.28%±11.98% to 34.45%±5.87%). At dose of H2O2 was 100 μmol/L and treated in 3,6,9,12 and 24 h, LDH-L and MDA were significantly increased after 9 h while NO and SOD were significantly decreased. In H2O2 dose of 100 μmol/L and action time 12 h, flow cytometry showed endothelial cellapoptosis rate was 16.92%±2.37%, significantly higher than the control group of 2.68%±0.47%(P<0.01); TUNEL detected endothelial cell apoptosis index was17.65%±2.36%, which was significantly higher than that in the control group of 3.23%±0.57%(P<0.01). The method was successfullyestablished a model of oxidative stress injury in cultured rat aortic endothelial cells, explore the moderate conditions that induced cells injury and apoptosis which could be a basis for the research.

Crocin protects retinal ganglion cells against H2O2-induced damage through the mitochondrial pathway and activation of NF-κB.

Glaucoma is a degenerative nerve disorder that results in irreversible blindness. It has been reported that the apoptosis of retinal ganglion cells(RGCs) is a hallmark of glaucoma. Oxidative stress is one of the major factors that cause apoptosis of RGCs. Crocin has many beneficial effects, including antioxidant and anti-apoptotic actions. However, the mechanism by which crocin protects against oxidative stress‑induced damage to RGCs remains unclear. The present study aimed to investigate the mechanism by which crocin protects RGC-5 cells against H2O2-induced damage. H2O2 was used to establish a model of oxidative stress injury in RGC-5 cells to mimic the development of glaucoma invitro. Different concentrations (0.1 and 1µM) of crocin were added to test whether crocin was capable of protecting RGCs from H2O2-induced damage. WST-1, lactic dehydrogenase(LDH) release and AnnexinV/FITC assays were then performed. Levels of reactive oxygen species(ROS) were detected using a ROS assay kit, mitochondrial membrane potential(ΔΨm) was analyzed by JC-1 staining, caspase-3 activity was examined using a Caspase-3 assay kit, and the protein levels of Bax, Bcl-1 and cytochromec were measured using western blot analysis. In addition, the protein level of phosphorylated nuclear factor-κB(p-NF-κB) p65 was also evaluated using western blot analysis. The results showed that crocin protected RGC-5 cells from apoptosis, decreased LDH release and enhanced cell viability. Additional experiments demonstrated that crocin decreased ROS levels, increased ΔΨm, downregulated the protein expression of Bax and cytochromec, promoted Bcl-2 protein expression and activated NF-κB. Taken together, the findings of this study indicate that crocin prevented H2O2‑induced damage to RGCs through the mitochondrial pathway and activation of NF-κB.

Protective Effect on Oxidative Stress Injury of Xiongma Dripping Pills Containing Serum on PC12 Cells

Object: The antioxidant dose-effect relationship and the mechanism of Xiongma Dripping Pills were study to explore the protective effects of oxidative damage in PC12 cells of different doses of Xiongma Dripping Pills containing serum. Method: Oxidative stress injury model of PC12 cells was established by peroxide hydrogen (H2O2), sodium nitroprusside (SNP), content and cell culture supernatant lactate dehydrogenase (LDH) and the liquid content of glutathione peroxidase (GSH-PX) were detected by chemical colorimetric determination. Results: There was a plasma concentration peaked in Xiongma Dripping Pills 8 times (6g•kg-1) dose group, ferulic acid plasma concentration was 10.59 ± 2.92, the plasma concentration gastrodin 18.13 ± 4.63. H2O2 and SNP could cause injury in PC12 cells, and increased LDH leakage, reduce the content of GSH-PX (P&lt;0.01). Gung Ma the Dripping Pills can reduce LDH leakage, increase the content of GSH-PX. Xiongma Dripping Pills 8-fold dose group content is the most significant.Conclusion: There was a significant protective effect on Xiongma Dripping Pills serum containing H2O2 and SNP induced oxidative damage of PC12 cells and its mechanism was relevant with clearing the free radicals, enhanceing antioxidant enzyme activity in vivo. There was the most significant effect on Xiongma Dripping Pills 8-fold dose group, and there was positive correlation on plasma concentration and pharmacological effects.

Lipophilicity of potent porphyrin-based antioxidants: Comparison of ortho and meta isomers of Mn(III) N-alkylpyridylporphyrins

Mn(III) N-alkylpyridylporphyrins are among the most potent known SOD mimics and catalytic peroxynitrite scavengers and modulators of redox-based cellular transcriptional activity. In addition to their intrinsic antioxidant capacity, bioavailability plays a major role in their in vivo efficacy. Although of identical antioxidant capacity, lipophilic MnTnHex-2-PyP is up to 120-fold more efficient in reducing oxidative stress injuries than hydrophilic MnTE-2-PyP. Owing to limitations of an analytical nature, porphyrin lipophilicity has been often estimated by the thin-layer chromatographic R f parameter, instead of the standard n-octanol/water partition coefficient, P OW. Herein we used a new methodological approach to finally describe the MnP lipophilicity, using the conventional log P OW means, for a series of biologically active ortho and meta isomers of Mn(III) N-alkylpyridylporphyrins. Three new porphyrins (MnTnBu-3-PyP, MnTnHex-3-PyP, and MnTnHep-2-PyP) were synthesized to strengthen the conclusions. The log P OW was linearly related to R f and to the number of carbons in the alkyl chain ( n C) for both isomer series, the meta isomers being 10-fold more lipophilic than the analogous ortho porphyrins. Increasing the length of the alkyl chain by one carbon atom increases the log P OW value ∼1 log unit with both isomers. Dramatic ∼4 and ∼5 orders of magnitude increases in the lipophilicity of the ortho isomers, by extending the pyridyl alkyl chains from two (MnTE-2-PyP, log P OW = − 6.89) to six (MnTnHex-2-PyP, log P OW = − 2.76) and eight carbon atoms (MnTnOct-2-PyP, log P OW = − 1.24), parallels the increased efficacy in several oxidative-stress injury models, particularly those of the central nervous system, in which transport across the blood–brain barrier is critical. Although meta isomers are only slightly less potent SOD mimics and antioxidants than their ortho analogues, their higher lipophilicity and smaller bulkiness may lead to a higher cellular uptake and overall similar effectiveness in vivo.

Iron Homeostasis in the Lung Following Asbestos Exposure

Human exposure to asbestos can cause a wide variety of pulmonary diseases, including pneumoconiosis (i.e., asbestosis). This lung injury is mediated by oxidant generation which increases with the concentration of iron associated with the asbestos. Iron from host sources is complexed by the surface of these fibrous silicates following introduction into the lower respiratory tract. Using bronchoalveolar lavage from unexposed and exposed workers, we demonstrate that asbestos disrupts the normal iron homeostasis in the lungs. Based on these findings, we propose a model of oxidative stress and human lung injury after asbestos exposure.

Manganese porphyrin reduces renal injury and mitochondrial damage during ischemia/reperfusion

Renal ischemia/reperfusion (I/R) injury often occurs as a result of vascular surgery, organ procurement, or transplantation. We previously showed that renal I/R results in ATP depletion, oxidant production, and manganese superoxide dismutase (MnSOD) inactivation. There have been several reports that overexpression of MnSOD protects tissues/organs from I/R-related damage, thus a loss of MnSOD activity during I/R likely contributes to tissue injury. The present study examined the therapeutic benefit of a catalytic antioxidant, Mn(III) meso-tetrakis(N-n-hexylpyridinium-2-yl)porphyrin (MnTnHex-2-PyP5+), using the rat renal I/R model. This was the first study to examine the effects of MnTnHex-2-PyP5+ in an animal model of oxidative stress injury. Our results showed that porphyrin pretreatment of rats for 24 h protected against ATP depletion, MnSOD inactivation, nitrotyrosine formation, and renal dysfunction. The dose (50 μg/kg) used in this study is lower than doses of various types of antioxidants commonly used in animal models of oxidative stress injuries. In addition, using novel proteomic techniques, we identified the ATP synthase-β subunit as a key protein induced by MnTnHex-2-PyP5+ treatment alone and complex V (ATP synthase) as a target of injury during renal I/R. These results showed that MnTnHex-2-PyP5+ protected against renal I/R injury via induction of key mitochondrial proteins that may be capable of blunting oxidative injury.

15-Deoxy-delta12,14-prostaglandin J2, a neuroprotectant or a neurotoxicant?

15-Deoxy-delta12,14-prostaglandin J2 (15d-PGJ2) is a potent ligand for peroxisome proliferators-activated receptor γ (PPARγ). However, its various effects independent of PPARγ have recently been observed. The effect of 15d-PGJ2 on neuronal cells is still controversial. We investigated its effect on neuronal cells (N18D3 cells). When N18D3 cells were treated with 15d-PGJ2, the viability was not changed up to 8 μM, but decreased at higher than 8 μM. The expressions of survival signals, such as p85 a phosphatidylinositol 3-kinase, phospho-Akt, and phospho-glycogen synthase kinase-3 beta (Ser-9), slightly increased up to 8 μM, however, decreased at higher than 8 μM. The levels of free radicals and membrane lipid peroxidation and the expression of c-Jun N-terminal Kinase increased in a dose-dependent manner, especially at higher than 8 μM. However, the expressions of death signals, such as cytosolic cytochrome c, activated caspase-3, and cleaved poly(ADP-ribose) polymerase, decreased up to 8 μM, however, increased at higher than 8 μM. In the study to evaluate whether low dose of 15d-PGJ2, up to 8 μM, had protective effect on oxidative stress-injured N18D3 cells, compared to the cells treated with only 100 μM H 2O 2, the pretreatment with 8 μM 15d-PGJ2 increased the viability and the expressions of the survival signals, but decreased them of the death signals. These results indicate that 15d-PGJ2 could be a neuroprotectant or a neurotoxicant, depending on its concentration. Therefore, some specific optimum dose of 15d-PGJ2 may be a new potential therapeutic candidate for oxidative stress-injury model of neurodegenerative diseases.