Please use this identifier to cite or link to this item: https://knowledgecommons.lakeheadu.ca/handle/2453/381
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dc.contributor.advisorSuntres, Zacharias
dc.contributor.authorPycko, Roxanne
dc.date.accessioned2013-02-01T20:14:10Z
dc.date.available2013-02-01T20:14:10Z
dc.date.created2012-06
dc.date.issued2013-02-01
dc.identifier.urihttp://knowledgecommons.lakeheadu.ca/handle/2453/381
dc.description.abstractOxidative stress is the imbalance between prooxidants and antioxidants within a cell that can cause and/or contribute to the progression of many pathological conditions. Reactive oxygen species (ROS) formed from the metabolism of hydrogen peroxide (H2O2) or paraquat (PQ) can damage DNA, proteins, and polyunsaturated fatty acids (PUFAs). A cell’s ability to defend against oxidative stress depends on multiple factors including genetic make-up, subcellular organelle function and environmental factors. Lipoic acid (LA) is an antioxidant with high reactivity to free radicals, but because of its low redox potential, it is also known to regenerate ascorbic acid and -tocopherol, elevate intracellular glutathione (GSH) levels and modulate transcription factor activity. We used A549 lung epithelial cells in an in vitro model to study the mechanism(s) of LA effects against H2O2- and PQ-induced oxidative injury. We observed that LA was incapable of protecting against H2O2 toxicity; thus, we used PQ as the agent to induce oxidant-induced damage. Challenge of cells with PQ resulted in decreases of cell viability and mitochondrial membrane potential and increases in DNA fragmentation and intracellular Ca2+ levels. Challenge of cells with LA resulted in an increase in cell viability, but a decrease in mitochondrial membrane potential. Interestingly, LA pretreatment of PQ-challenged cells resulted in the potentiation of DNA fragmentation and intracellular Ca2+ levels. Our results indicate that LA enhanced the PQ-induced oxidative injury in A549 lung epithelial cells, perhaps by acting as a prooxidant.en_US
dc.language.isoen_USen_US
dc.subjectOxidative stressen_US
dc.subjectReactive oxygen speciesen_US
dc.subjectOxidative DNA damageen_US
dc.subjectHydrogen peroxideen_US
dc.subjectParaquaten_US
dc.subjectLipoic aciden_US
dc.titleLipoic acid and its potential role in the treatment of oxidative-induced injury of A549 lung epithelial cellsen_US
dc.typeThesisen_US
etd.degree.nameM.Sc.en_US
etd.degree.levelMasteren_US
etd.degree.disciplineBiologyen_US
etd.degree.grantorLakehead Universityen_US
dc.contributor.committeememberMalek, Ladislav
dc.contributor.committeememberKhaper, Neelam
Appears in Collections:Electronic Theses and Dissertations from 2009

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