title: Modulation of early stress-related biomarkers in cytoplasm by the antioxidants silymarin and quercetin using a cellular model of acute arsenic poisoning.
abstract: Several pathologies (e.g. cancer and diabetes) are increased in arsenic-exposed populations, with oxidative stress being a major toxicological mechanism. Since the flavonoids silymarin (S) and quercetin (Q) are antioxidants and may protect cells, it would be valuable to develop a model which allows assessing the potential of xenobiotic against arsenic cytotoxicity in an efficient and rapid way. Thus, the oxidant production [e.g. reactive oxygen species and reactive nitrogen species (RNS)], the molecular parameters of biological response [e.g. plasma membrane composition, actin microfilaments and activated diphosphorilated c-Jun N-terminal kinase (JNK)] and cellular viability were determined in CHO-K1 cells treated with arsenite (As), S and Q. Arsenic caused loss of the cellular viability in a time-dependent manner. This effect was accompanied by a lipid hydroperoxide (LHP) formation, with no RNS induction or ganglioside content changes being found. Both flavonoids counteracted oxidative damage. Despite all treatments had unspecific responses on nitrite cellular release along the time, there was no relation between them and the cellular viability. Arsenic induced cytoplasmic microfilament rearrangement (tight perinuclear distribution with projections, stress fibres and pseudopodia) which was reversed by S. Also, activated JNK showed a similar distribution to actin. Contrarily, Q caused a dysmorphic granular pattern, thus behaving as a toxic agent. Summing up, toxic levels of arsenic disturb the redox homeostasis with LHP induction and early triggering of stress responses in cytoskeleton and cell signalling. Using the proposed model, only S showed to protect cells from arsenical cytotoxicity without own toxic properties. Thus, S might be considered for modulation of the human arsenic susceptibility.
authors.affiliation: Cellular Biology Institute, Faculty of Medicine, National University of Cordoba, Argentina.
authors.forename: Elio A
authors.initials: EA
authors.lastname: Soria
authors.forename: Aldo R
authors.initials: AR
authors.lastname: Eynard
authors.forename: Guillermina A
authors.initials: GA
authors.lastname: Bongiovanni
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D020261:Arsenic Poisoning / Q000378:metabolism*; D018053:Arsenites / Q000633:toxicity*; D015415:Biomarkers; D016466:CHO Cells; D002470:Cell Survival; D002478:Cells, Cultured; D006224:Cricetinae; D003412:Cricetulus; D003593:Cytoplasm / Q000378:metabolism; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D008054:Lipid Peroxides / Q000378:metabolism; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D011794:Quercetin / Q000494:pharmacology*; D012838:Silymarin / Q000494:pharmacology*
chemical_list: D000975:Antioxidants; D018053:Arsenites; D015415:Biomarkers; D008054:Lipid Peroxides; D012838:Silymarin; D011794:Quercetin; D048031:JNK Mitogen-Activated Protein Kinases; C015001:arsenite